# Viewsonic VX2235wm-5_a simple Multi meter question



## murihikukid

Hi.I am trying to repair a Viewsonic VX2235wm-5 Monitor and sought help via a "forum"...Everything was going great then it seems I have been divorced..IE replies have suddenly stopped which puzzles me...So I wonder if anybody could just give me guidance here please....There are two Circuit boards on the VX2235wm-5...Everybody seems to call them different names but I will refer to them as the Power Board (where the AC input ,capacitors etc are ) and the video circuit board ...the two boards connect together via a 8 pin plug/socket....Now what has been established is that on the Power Board a fuse F101 which feeds the Logic Board which I presume is the Video Circuit board is no good....

I have been told to <put the multi meter in ohm mode ,black lead to the chassis and red to the top end (the end connected to the 8 pin connecter ) of the F101 Fuse and take a reading >

Now I understand this but the boards have to be "removed" from their mounts to enable a multireader to get a reading (from underneath of board)..So I needed guidance on this and thats where I am at....You see I do not know whether to remove both boards and connect them together and somehow take a reading as asked (I presume the ground part of the board where its attached to the chassis by screws is the same as the chassis itself ) or what??? SO I am confused by how to get the reading as asked ...So I wonder if somebody could just enlighten me here....Thanks HK


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## octaneman

Hi HairyKiore


When you are testing boards for their components you first disconnect the power and drain the main capacitors on the power supply. Be very careful when you do this because power supply capacitors carry high voltage. Keep in mind that voltage before the rectifier is A/C and after the rectifier is D/C. 


There are 2 methods when testing PCB's 1) power off 2)power on. the first method is you do a preliminary inspection of components, resistors, capacitors, transistors, etc for any burn outs. To get accurate readings on your meter, the boards that connect to a power supply have to be disconnected and removed. Some components like for example transistors need to be desoldered from the board because the rest of the circuit will draw a little current from the meter itself just enough to obscure your readings. To test transistors you set your meter on diode. 


Testing a board with power on is more accurate because what you are essentially performing is a voltage drop test across the whole circuit. You really have to be mindful of where you place your leads and what setting your meter is on. For example testing for amperage is not the same as testing for voltage. Voltage readings is you place your positive and negative leads in parallel to their respective polarity (positive, negative) set your meter on DC volts and you get your readings. For amperage you have to set your meter on AMPS open the circuit path, (desolder the pins) and place your leads in series ( in a straight path) between the two components within the circuit and take your readings. If you hook up your meter in parallel while in AMPS mode you will blow your meter beyond repair.


For your particular case what you do is disconnect the 8 pin connector, set your meter on D/C volts connect the negative lead to chassis ground and use the positive lead to probe the the pins for power. Each pin gives a specified D/C voltage to a specific part to the other boards. For example. If you probe all the pins and all of them have the same voltage across, it means that that either an opto-isolator circuit isn't working or a power transistor isn't switching.


Note: Always use a schematic before you do any type of circuit testing.


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## murihikukid

Hi..Thanks for your comprehensive reply....I now have a 1/4 watt 1.2 ohm resistor soldered across the F101 fuse which is obviously blown...I have powered up my PC and the monitor connected together....I now have lights on my monitor but nothing from my PC IE Windows...
I now presume with my limited knowledge that the Power/inverter board is ok and that the problem is with the Logic/Video board...I have switched everything off at the wall but the monitor's Power board and Logic board are all open to take any reading at the 8 pin connector either with power on or off.. I just wondered if by taking any reading at any of the 8 pins would give an indication what the problem is...I am no technician so just hope I have explained my situation satisfactory for you ..Thanks :dance:


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## octaneman

HairyKiore said:


> I just wondered if by taking any reading at any of the 8 pins would give an indication what the problem is...I am no technician so just hope I have explained my situation satisfactory for you ..Thanks :dance:





Yes it would, the 8 pin connector supplies X-amount of voltage to whichever circuit a particular pin is connected to. From the power supply the voltage regulator on average gives 14 to 15 volts that goes to the inverter/logic board. The logic card would then convert it to lower voltages typically 3.3v and 1.8v (+ or - 0.2v) which sends power to the LCD panel. The logic card sends control signals to the inverter, which controls the power LED. This is the basic set-up for all LCD monitors.

For example; If pin 5 had to supply +3v and your meter would read 1v, it means that some component an I.C or resistor thats soldered along the trace is getting hot drawing too much power. If you got no readings at all or over voltage it means that the supply voltage from a transformer or some component isn't switching on. If you don't have a schematic you would have to follow the trace visually all the way to the source, this is a painstaking process and very time consuming. 

When you say that you have lights on your monitor is the power on/off indicator illuminated ? What color is the LED ? Does it blink ? Some viewsonic monitors carry an 50117K-G voltage regulators does yours have one ?

Can you post a picture of your monitor's board ?


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## murihikukid

Thanks for your Reply ...Although with the Resistor soldered across the F101 fuse and the back lights now on there is no lights on the power on/off indicator..
I have attached photos of the Power Board ,Logic Board and under the power board where the resistor has been soldered...Thanks


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## octaneman

No lights to the power on indicator means you don't have the +5v standby, you need to check the stand-by voltage rail from its main source. Without the 5 volt reference the power supply can't power up the rest of the board.


What are the voltages coming out from the 8 pins ?


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## murihikukid

OK..Can you please tell me if this is what I do...Put the Power Board back onto the chassis and connected via the 8 pins to the Logic Board ...I then power the unit up and with my Multimeter set at 20v and the black/negative lead to the chassis record each reading from all 8 pins with the red lead ..Thanks


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## octaneman

HairyKiore said:


> OK..Can you please tell me if this is what I do...Put the Power Board back onto the chassis and connected via the 8 pins to the Logic Board ...I then power the unit up and with my Multimeter set at 20v and the black/negative lead to the chassis record each reading from all 8 pins with the red lead ..Thanks





Right on, write the voltage readings down on a piece of paper and please post them. Also write down the numbers of each I.C thats soldered on to the power board you will need to trace the 5volt reference voltage from the pin directly to its source and to the on/off switch. On your power board where the 8 pins are next to the capacitors, there are voltages and the pin's designation that are printed on to the circuit board those are the voltages that your meter must read. I can see from the picture's orientation starting from the top pin 3 is the +5 volts. Is it there ?


Note : On the bottom edge of the power board there is a heat sink with I.C's past the capacitors. There is more information printed on the board with another +5 reference. Have you tested those pins with your meter ?


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## murihikukid

Hi..I am just doing the tests now...Unfortunately its not a nice day as I find it best at my age to take things outside and use a magnifying headband to see them properly ..I now find taking a digital photo will give me far better results than a magnifying glass??...I will get back with my results soon but I am supposed to be changing my ISP today so if I disappear for a day or two that will be the problem..also sometimes I do find it difficult to understand what part is being referred to and wonder would it be possible to mark anything that you are referring to on one of my photos ...Thankyou HK..


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## murihikukid

Ok..I have done the tests but I think I have problems...I have two identical cheap multimeters and they give varied results.....
Here are the readings ..top to bottom.. with +5v being the 4th pin (not the 3rd)
000
-001
-001
751 > the +5v pin
1
000
484
475
At a guess I do not think these look good and wonder if I need to invest in another Multi Meter..
I have attached some more photos including one of the 8 pin connecter with my multi meter readings printed on it.. Thanks


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## octaneman

Using cheap multimeters will not give you the desired results with any accuracy, in a job like this there is no room for inferior multimeters. It is best you get yourself a decent meter because you have to distinguish actual voltages from ghost voltages. Ghost voltage means that your meters can't get a solid fix. Your meter readings tell me there is no main power going to the logic board with a voltage regulator not working.


What we'll do is focus on the power board first before moving on to the logic board. The logic board will be disconnected until the voltages on the 8 pins are found and are stable. Without those voltages being there it is pointless to move on to the rest of the diagnostics. If you are up to the challenge we'll take this one step at a time and test components until they are found, by the end of this you will become an expert in the use of multimeters.


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## murihikukid

Hi..Re Multi Meter..I have had a good look on the online auction network here and outside of Fluke it looks like a minefield ...I cross checked some on Google and a couple looked like they could be a reasonably priced,good meter for my needs ..I am going to bike up to the city and check a couple of shops out and see what they have but it will probably be the same as whats online but more expensive... Of course my problem is identifying a good one from a bad one? You are very kind in offering your help ..and if you are willing to put up with me I would be extremely grateful..I am getting ancient so I find it difficult with some things....Re the Logic board ...Yes I can remove it ...now I recall at some stage in my life I have disconnected a ribbon cable from a circuit board but as I understand there is different connectors ...I presume its best to just check with yourself on how best to disconnect the cables instead of me just guessing and doing damage....Thanks HK


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## murihikukid

Hi.. Re Multi Meters..I hope one is allowed to put links in a post? or if they actually show as links ...But I can only try ...I have been doing a lot of finding out whats on offer here..online and from city shops ..I thought either of these might be best ..
495# VICTOR VC890C digital multimeter for sale 
One is available here online 
Victor Multimeter Model VC890C+ | Trade Me
Its not new but has not been used? But seems to me to be a more expensive model than others ...which of course does not make it better..

OR
Digital Multimeter | Trade Me 
Its a Digitor Q1467 .....and is sold by our equivilant of Radio Shack
Dick Smith Digitor 19 Range Digital Multimeter : Questions, Answers, How To, FAQs, Tips, Advice, Answers, Buying Guide

The Links below are either for a multimeter available online here or the actual online link itself...
DT-830L 
XL830L Digital Multimeter - US$ 10.58 
http://www.trademe..co.nz/business-...equipment/gauges-meters/auction-460056303.htm 
DT830B, the best seller in the digital family ! 
Digital Multimeter - Budget Price | Trade Me
multi-meter digital multimeter brand new | Trade Me
Digital Multimeter XL830L | Trade Me
Professional Mastech Multimeter MS8213 | Trade Me
EM-M01 DIGIT Multimeter Voltmeter Ammeter Ohmmeter | Trade Me
Multimeter Packed with Features - Quallity Build | Trade Me
DT-830L
QM1523 Digitech Digital Multimeter :: Multimeters :: Test & Measure Equipment :: YankeeRoo
DT830B, the best seller in the digital family !
XL830L Digital Multimeter - US$ 10.58

You may spot one that stands out and that you would recommend ..Thanks HK


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## octaneman

That ones that stick out is Victor VC890C or Victor VC890C+, for a simple reason is I'm aware of Victor, they make amazing meters which come with a few bells an whistles that come in handy. The better accuracy of the meter the more expensive its going to be. Cheap meters are just that ...cheap. A split second of carelessness and they give up the ghost which in a job like this will make you fire off a few colorful expletives. Good meters have sensitive circuit protection and durability that will prevent it from going up in smoke, this is what all technicians that I know (including myself) look for in meter. 

When you get it make sure it has its manual, get comfortable with it know all the functions before you touch the monitor's PCB. If you don't understand any of the functions don't be shy in asking questions were here to help. 

When you're ready we'll begin the diagnostics.


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## murihikukid

OK..Yes I noted the VC 890C on an California website for $127 ...Actually I found a listing for an unused meter not far from where I live ..
Digital Multimeter | Trade Me
..there was no manufacturer etc listed so I zoomed up the photo to get a model # and found it was a Victor 890C .. the seller has poorly listed it and its at $5 and finishes Sunday and I would be surprised if he gets a taker (except myself)....I did note a few brands that had good feedback on the internet but apart from Fluke they do not seem to be available here ...All the rest are much the same..So I will be able to give you a weeks rest ?? til I can get it posted down to me...thanks


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## murihikukid

Hi..I thought I better let you know I am still here...I have actually bought the Victor VC 890C Multimeter but the seller is being rather annoying as so far he has not posted to me even though I told him I was wanting it as soon as possible... Hopefully I will get it by the end of the week ...Hk


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## octaneman

While you are waiting for your meter to arrive, we'll need to do research on the main power board IC's to know what they do. Please post the serial numbers on all the IC's starting from the AC/DC rectifier thats next to the large capacitor CE106. 

Post the IC numbers for:

Q102 
U102
Q103 (x2)
U101 
Transistor (bottom right next to T100)


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## murihikukid

Hi...Right ..I can only do my best ..I actually need a hand held Magnifyer as well as my headband ...If it was not a sunny day I doubt if I could read any of them ..Going by the photo attached heres what I have...
The IC next to the CE 106 Capacator and circled A says
P6NK60ZFP
GK01M V6
CHN 735

*U102* is circled B
20735
817B..I do not think its 8178 but it could be?

Transistor Bottom Left next to T100..Circled C
I presume its the one you mean ...Now If I Can remove the heatsink as explained in following paragraph I may be able to read whats on it ...I just do not have the experience to know if the transister pins would allow me to bend the transister gently over to the left so that the side is slightly upwards..There is a fair amount of goo round the base .I just feel the heatsink removal should allow C,D and E to be read..I have just had another look and realised the heatsink is soldered to the board ??

*Q103 (x2)* They are actually D102 and D103,,Aghhh now i see where the Q102 is ..I presume its D102..Circled D and E ..there is no way I can see what is printed on these ..If you absolutely need them can you suggest a way to get at them IE is the heatsink held in position by the Screw on Each IC and if the screws are removed (even if that is possible) and the heatsink removed...what would happen if the IC's were gently bent to the left to see if the info can be read... 

*U101* Cicled F
ZM317T
GK06V VW
CHN 735

Now there is also a small circuit board that I have circled G.....It looks to me that this will pull out ...On the board is another IC that you may want a reading from..

Sorry thats the best I can do ... at this stage .. I only hope I have got the right parts you refer too.....Just to make the situation worse I sent an email to the guy I bought the Multimeter from and there is not even a reply even though I told him it was urgently required..??? I may have to buy another one...Thanks HK


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## murihikukid

Further to my earlier Post there is IC 's under the Power Board ..would you like me to take a photograph of the underside?...you may want what is there identified also...Now the Heat Sink has two solder anchor points to the power board so I presume if these are de-soldered and the IC screws removed it will come off easily and hopefully enable the IC's to be identified.....Thanks


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## octaneman

Taking a picture of the other side would be a great idea especially where the 8 pins are so we'll be able to follow the traces and take any I.C numbers along the way. As for the components circled A,E,D,F on heat sinks the best and easiest way is to remove the screw to see the numbers without desoldering them, just flip the board every which way you can to see the numbers. If you feel you need to desoder them just desolder the component desoldering the heat sink isn't necessary. Use a flashlight and a magnifying glass if you have to because having those numbers are important in your diagnostics. 


For the transistor (circled c) you can bend the transistor over quite a bit without doing any damage to it. The numbers on it are quite small but are readable, just take your time in taking the numbers down. The prefixes could start with 1N,2N, BC,SN, 74B or something similar. The next step will be getting the datasheets to locate their testing points.


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## murihikukid

OK...I have had another look at the power board ....In my opinion there is no way I can decipher D102 and D103 ....by just removing the screws....I have attached a photo of under the power board and circled in yellow the two solder spots that hold the heat sink in place ...with the heatsink removed I can lean D102 and D103 slightly backwards ..and I then hopefully will be able to see the markings on both... and see the transistor markings also...The Capacitors are so close to D102 / D103 that without leaning the IC's there is no hope no matter what I use...Also my small knowledge of Electronics tell me it would be far easier and safer just to suck up the solder where the Heatsink is anchored ...remove it and when one has the markings ....solder it back again...But then again I might be wrong...Cheers HK


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## octaneman

If you have to remove the heat sink then by all means do so just orient the board so it would be easiest as possible to get at the numbers, be careful not to damage any of the copper traces on the board.



From your board I see there are 3 surface mount fuses that need to be checked under the power board. I've circled the fuses in red and marked them A, B, C, now you have already soldered a 1/4 watt resistor on the board and I can understand why you did it. When you get the meter we'll test them first one at a time properly.


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## murihikukid

Hi..Could I request that you use another colour other than red against green..I am supposed to be colour blind and find it extremely difficult if not impossible to read ..I can barely make out 2 red circles but no numbers....With no multimeter arriving today and Good friday tomorrow its now evident that it will not arrive til after the holiday period...He has been paid enough for shipping for a same day courier ??....In all my years using online trading I have never come across such a poor communicator than this particular guy and he is taking up to 4 days to reply to an email.... Just to think I could have bought the identical meter from another source for a few dollars more and would surely have it by now from over 1000 miles while this guy is 100 miles up the road?? 
We have had beautiful Autumn days and today is probably heading for 20 degrees and I will soon be taking my soldering bolt/sucker etc outside in the sun to get the info from the board for you..HK


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## murihikukid

OK..I was hoping that this would not happen>> D102 / D103 are connected to the heatsink by a Phillips Screw and its impossible to get a screwdriver on them ...I have tried a pair of clamp surgical pliers but they just slide off the screws head and I cannot think of any tool that I have that would clamp onto the Screwhead sufficiently to turn them ...Obviously the designer of the board never meant them to be removed...My options are to remove the heatsink and IC's all as one??? or remove two capacitors that may enable me to get a screwdriver at the screw heads.... I note the Capacitors have been put on the board with the leads pushed up to the hilt if you get what I mean...again with my limited experience I would at a guess presume that removing the two capacitors would be the safest way to go ..I look forward to your comment on this... HK


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## murihikukid

In the past I have always used a desolder sucker but I see a wick may be the way to go so I am going uptown to get a roll..While I am there I will check with the electronic shop and a nearby hardware shop if they have a tool that may remove the screws....HK


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## murihikukid

OK..Got some solder wick and came back home and found a small pair of pointed vice grips...I ground the sides of the points down to around 1/4 inch thick and this allowed me to grip the screw head and loosen them so I am part way there.....now to desolder.....HK


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## murihikukid

Sorry about all my postings but it seems I have another problem ...Would the solder that is on the heatsink lugs be a special high temperature solder...My soldering bolt is not making any impression on it...??? Yet it is plenty hot enough to melt normal solder... Thanks HK


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## murihikukid

Its simply a waste of time trying to desolder the heatsink ..It must need a blow torch?? on the bright Side I have Identified D103 that is screwed to the heat sink....
it is...
SBT150
107G4

but I am 99% sure its partner D102 has no lettering on it at all...
Re the Transister...the heatsink completely blocks the printed side and with all the white goo it has round the leads its impossible to bend UNLESS the White goo can be removed??...HK


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## octaneman

Yes you could remove the white goo use an Xacto knife to cut away at it a little at a time. All semiconductors have numbers on them if you have a problem reading it, try to get as close as you can with a camera and take a snap shot and I'll take a look at it. 


2 Questions:

1) What color do you prefer that I use to make it easier for you to see ?

2) Will you be able to see symbols and test points from a data sheet to be able to take readings with the meter ?


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## murihikukid

Hi...Yes I know where the numbers are so will see If I can get Rid of the goo...It seems Blue against green is best but any colour other than red with green..or yellow and red would do ...and yes I will be able to see symbols etc from a data sheet.. I can see colours like on an aircraft?? its when green/red and yellow/red are blended together like in a telephone book I have real difficulty.. 
Hopefully the cloud will burn off outside and the sun will come out as the forecast says...It makes a real difference outside in bright light seeing things...Hk


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## octaneman

I've marked the other 2 fuses in yellow (as you requested) that are on the underside of the power board as A, C (one you know of already) their designations are F100 and F200 as I stated in an earlier post. I don't know if you noticed them before or tested them but we'll do it again. 

I'll be posting the data sheets soon because you'll need to know their orientation from the data sheet to the actual component on the board on how to place your meter leads. I'll use simple terms without the technical jargon to explain to you what they do so you won't be confused when the actual testing is done OK ?

Would it be helpful to you if to post the diagrams in larger size ?


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## murihikukid

Hi..Re the Data Sheets ..its always better to zoom in than out so posting in the larger size is probably better....Re the transister ...The goo is that tough even a box cutter will not touch it..I also tried a file but its clear to me that removing it would be near impossible and the likelihood of damage is just too great...Apparantly Heat Sinks are not designed to be removed ..that would still be my preferred option but if I cannot de solder the lugs that option is not possible so this leaves me with a reflection surface like a small mirror that I can place between the heatsink and the transister flat facing ...Its very narrow but it may work...I will go up town tomorrow and see if I can find a mirror ..Thanks HK


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## murihikukid

Hi ..Heres the Transistor ..You may be able to read it?? I have taken about 20 photos ...the one attached is the best I have come up with unless there is a magic formula in taking such photos.. Please let me know if it helps ..it is of course a reflection ...HK


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## murihikukid

Hi...The White goo melts ??? so I have removed some of it and gently bent the transister backwards away from the mirror ...When I tryed to get more photos the camera indicated the batteries were flat?? However I now believe that I will get the transister identified for you......Hk


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## octaneman

Sorry, the numbers are not clear on the picture you sent so I can't make it out. I've posted the data sheets sheets for the IC's I've found so far. The ZM317T IC is proving to be quite a PIA to locate but I'm not giving up. In the mean time when you get a chance study the diagrams to the best of your ability, you need to know how these work before you begin your diagnostics. Some terminologies will be difficult at first to understand, but as you progress through the testing phase everything will become clear to you so don't worry about anything OK ?. I've posted a picture of the 817B optocoupler for you to get a better idea of what it is because the datasheet picture will be too small for you to see.


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## murihikukid

OK..I have taken over 40 photos outside at various angles with degrees of light as the sun breaks out behind cloud...I still do not understand the camera so thats also a problem for me and unfortunately I feel that even if I spent all day taking photographs... what I have attached is the best I got..But not good enough..I do not understand how to take a real closeup ?? I have tryed but they are out of focus??
So I am hoping that the local library has a magnifier and when they open after easter I can take the board and my magnifyer headband up there and then I am sure I can establish what is printed on the Transister...By then the multimeter may have arrived...HK


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## octaneman

I can barely make out the numbers but I believe its a TL431 transistor.


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## murihikukid

Hi...How did you read that???? You are 100% right ...I found my jewellers/stamp eye magnifier that I knew I had somewhere (more by luck than anything else ) and with my headband magnifier and because its a nice day I was able to manipulate the board into the light and finally there was the number TL 431...Amazing I then rechecked it and it took me another 10 minutes to actually see it again?? HK


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## octaneman

There is another transistor next to it can you post that number also ?


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## murihikukid

Yes..I presume its the flat 4 lead component next to the transister..Here again I have a small problem as the fIrst letter looks like an upside down 7 ...but I presume it could be a Z with the top indistinguishable...so here is what I have come up with ....
ZO735
817B
v
I hope these letters will identify it...
I have now been told the multimeter was posted last Wednesday ..as he would not have received my payment til last Thursday I presume that was when it was posted...Postal services do not resume til tomorrow Wednesday so I have my fingers crossed it will be in the letter box with 18 hours.. HK


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## murihikukid

I presume its the component circled B...is the transister you are referring to..HK


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## octaneman

No, The "B" is the photocoupler I was refering to this picture you posted.


Question:

How long do you estimate it will take to recieve your new meter ?


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## murihikukid

Oh??? There is only one Transister ..in the attached picture ...Thats a mirror reflecting the transister ??

The Multimeter has arrived ... I am surprised at how large it is ..its about 40x larger than the multimeter I was using previously ....It was in a box but with no padding (not even some crumpled paper round it to stop it moving round in its box in transit...I get annoyed by that )....Now there is a single screw rolling around inside the box ...Do you mind if I post a picture of the Multimeter ....I think I know where the screw comes from but you may be able to verify this for me..Theres no manual etc but I have downloaded it from the internet..and I presume no battery so I guess it needs a good quality 9v ...HK


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## murihikukid

Ok..Heres pictures..It looks beautiful in brand New condition..Unused ...I have circled where it looks to me where the screw goes...But I could be wrong..By the way I did check local Electronic shops as regards Multimeters and there is nothing like this unit in any of them ..I got the VC 890C for $20.50 including $8 shipping so thats not too bad ..HK


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## murihikukid

Aghhh..I should have investigated properly...I now know what the screw is for ...There is actually a battery in the unit and there is a slide cover to the battery compartment ..when the cover is slid in fully in place.. the screw is then screwed in which locks the cover in so that there is no way the cover can come off..SO will check the battery and I presume I set MM to 200ohms and check the fuses you referred to in an earlier post..At 200ohms and leads touching I get a reading of 00.2.... HK


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## murihikukid

OK..I have checked the fuses marked A and C that you circled in a previous post with the MM set to 200ohms ...I got 00.2 on both....the Fuse circled B of course did not register and that is why the resistor is soldered across it.....Thanks HK


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## octaneman

Thats great ! 
Awesome meter by the way congratulations you got yourself a beauty now we can begin the diagnostics.


First you are going to redo the fuse test on your meter there is a symbol that looks like a horse shoe its white and its just below the 200 ohms range on your meter. This is for continuity it gives out a tone to indicate there is a connection, in electronics it can mean there is a short or the connection is good. I want you to familiarize yourself with it because you are going to be using it allot. The second part you will familiarize yourself is with the readings of infinity. Infinity means infinite resistance * NOT 0.00 * it means that the meter has reached its maximum capacity which is represented on some meters by the letters OL. The real meaning of OL is Outer Limit which some people wrongfully interpret as overload. 


The first test you will do again are *ALL * the fuses on the power board including the main one thats near the A/C jack. Set your meter on continuity, connect your meter leads together to verify you have a tone. Place your probes on the fuses if you hear a tone the fuses are good if you hear no tone the fuse is bad. On some meters the continuity setting also acts as an auto range finder, so for the fuse resistor the meter should pick it up. 


When you are done we'll begin the next stage by verifying the voltage readings on the pins. Set your meter on DC volts connect your black lead to one of the ground pins and use your red lead to probe the +5v and +13v. One thing I must point out you have 2 ground pins, one is for negative voltage the other positive. If you get a negative voltage reading on your meter just move your negative lead to the next ground pin. When you do this please take your time be real careful not to short out anything. 

post back both your voltage and fuse readings.


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## murihikukid

Thanks..Please advise if any of these tests require the power board to be put back in its proper place on the monitors chassis and the power actually applied...HK


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## murihikukid

ok..I have tested all the fuses that I know are fuses IE The one that is near the AC Socket..(F103) and also F100 which equals the A circle and F200 which equals the C circle as you marked....With the MM set to continuity ..Got a tone on all tests...
Now you ask for verifying the voltage readings on the pins. I presume the pins you refer to are the 8 pins that connect the Power Board to the Logic Board..also at this stage I presume the readings you require can only be obtained when the Power board and Logic board are once again joined on the chassis and power applied...HK


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## murihikukid

I wonder if you want a reading from all 16 pins ...There is a row of 8 at the top and another row of 8 just underneath ...These are as marked on the board..
AOL-, AOR-, MUTE, +13.8v, +5V, GND, GND (only 7? )
Corresponding under pins...
AOL+, AOR+, SHUT, v_adj, +5v, DET, GND, EVA,
...HK


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## octaneman

The more pin voltages we have the better it is for us to isolate where the problem is. The board which has your on/off monitor switch will be focused on more because you will need to test the switch and see if the +5v standby is there. 

The boards do not have to be assembled to get the readings, for now we are only interested in the power board. Grounding your black lead can be accomplished in 2 ways. The first way is to place the ground lead on the pins marked GND and the positive on the positive pins. The second way is to ground the black lead onto a heat sink with an alligator clip and begin to probe for power with the red lead. For example; such as polarized capacitors on the positive side . These methods of connecting your leads is for measuring DC volts *ONLY* 


Now that you have determined that there is continuity on all the fuses it means that they a have tested good. If your meter did not emit a tone on the fuse test then the resistor would be soldered on the board. 

Question: If you remove the home made resistor fuse is there continuity on the board fuse ? 

Once you post the voltage readings we'll go onto the next step.


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## murihikukid

Right..heres where I get confused...I thought that in order to get a voltage reading at the pins there would have to be power applied ..or am I wrong?..I can actually remove or install the power board on the chassis in 30 seconds and power it up and use the chassis itself as a ground .. in fact I find that with the power board on the chassis it is solid ,will not move around... so easier to take readings...Re the resistor fuse ..after I get the voltage readings I will remove one end of the resistor (fuse )and take a continuity test ..HK


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## octaneman

You're right, power has to be applied do what you feel is necessary to get accurate readings.


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## murihikukid

Hi...I suppose a small shock using a multimeter is part of the learning game??anyway heres the voltages for the 8 top pins..with multimeter set to 20v.

AOL- = 2.51
AOR- = 2.51
MUTE = -0.00
+13.8v = 14.33
+5v = 4.10
Grd = -0.00
Grd = -0.00
8th pin = 2.64

I also noted when I powered up everything the backlight is now not going...
I am now going to remove the power board ...disconnect the resister and do a continuity test on the fuse so will be back with a result in 15 minutes...I really like this multimeter...without your help I would never have known what to buy..Thanks Hk


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## murihikukid

Question: If you remove the home made resistor fuse is there continuity on the board fuse ? There is NO continuity on the board fuse...Hk


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## octaneman

To answer your fuse question, if the meter does not show continuity with resistor removed the fuse is burned. 

The voltage readings you provided now paints a very different picture from what was given from the beginning of your posts. The board is partially functioning from the main +13v being present which now brings us closer to where the culprit is. 

Now we come to main source of where the problem is. On the +5v pin the readings you took indicate 4.10v this is a low voltage. The pin *must* have no less than +5 volts which clearly indicates that there is a " thief " within the board stealing nine tenths of a volt. That 9 tenths of a volt is what you are going to track , so with a few tricks I will show you how you're going to locate it. Keep in mind that you're board is a regulated power supply and that the voltages must be at the pins at all times. 

Now here's how you are going to track it.
Our " thief " is hiding in one of 4 places; 1) A bad transformer, 2) a bad regulator, 3) a leaky capacitor 4) a bad diode. The first part of our strategy will be looking at the capacitors, capacitors are finicky things and on allot of occasions fool us into believing they are working properly. The capacitors on your board are polarized capacitors, which mean that they are connected to the board in relation to their polarity. Capacitor filters out A/C voltage allowing a clean DC to flow throughout the board unobstructed. 

Here's the trick: Since we know that A/C cannot be present on the D/C side of the board, you will set your meter on A/C voltage to locate the spot from where its leaking an guess what ? On the heat sink next to the capacitors we got a voltage regulator diodes on D102 and D103 which has been identified as SBT-150 and this is our starting point. 

Open the SBT-150 rectifier pdf file and you will see the diagram of what the inside of the regulator looks like including the pin outs. You will see on the diagram that the center pin is ground and the left an right pins are diodes. Now diodes are one way valves which means they conduct one way *only* 

You will power down the board set your meter to continuity test, place your negative lead on the center pin of the SBT-150 and the positive lead to the left side of the pin. Your meter should get a reading, then you will reverse your leads on the same pin your meter should read infinite resistance (OL remember ?). If you get a reading when you reverse your leads then that part of diode is gone. You will do the same thing to the right pin, place your negative on the center pin and probe the right pin. Your meter should get a reading and when you reverse your leads no reading. 

To get accurate readings from the meter you will desolder the pins to the SBT-150 and then do your diode readings ok ?. 


On diodes there are two things to remember; 1) If your meter gets readings on both sides it is considered a "shorted" diode which needs replacing. 2) If the meter does *not* give you any readings at all on either side its considered "open" which also has to be replaced. *Remember your meter should read the diode on one side only !* 

This is your first test that you will do with power off and then we'll move on to testing the same component with power on stage. On the power on stage we will be hunting down our " thief " using the bounty hunter's A/C scale on the meter, the technical term is called testing for ripple voltage. 

post back your findings.


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## murihikukid

I hope you do not mind if I double check with you..As I understand I have to desolder the voltage regulator diodes D102 and D103 and remove them from the circuit board completely in order to take readings from them ..I do note that between the diodes and the heat sink there is a compound ...does this have to be renewed when the diodes are screwed back against the heat sink.....Hk


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## murihikukid

Also..If the Diodes turn out to be OK do I solder them in again ....and what next? as tomorrow I have a few free hours...Hk


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## octaneman

You don't have to remove D102, D103 from the board completely all you do is desolder the pins to the SBT-150 for now and leave the rest intact. It will save you time and energy of putting everything back when you will do the power on test. Do it this way because even if they turn out OK with power off, they may tell a different story when you verify their condition with power on. 

FYI: The compound thats on the diodes is white silicon grease to help dissipate heat better it acts as a thermal insulator. Don't remove the grease from the diodes or any other component thats on a heat sink because you will have to re-apply it if it ever comes off.


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## murihikukid

Sorry I am confused..in fact I am lost....D102 and D103 are both SBT-150's ...aren't they... 3 pins each to the circuit board....and you want me to desolder these pins..I presume best I can?? 

Re the diodes ...When I thought I could remove the heat sink I first had to loosen the screws holding the diodes to the heat sink ..One screw came completely out and the diode moved breaking the seal of the white silicon...I have put the screw back in and loosely tightened it..Hk


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## octaneman

HairyKiore said:


> Sorry I am confused..in fact I am lost....D102 and D103 are both SBT-150's ...aren't they... 3 pins each to the circuit board....and you want me to desolder these pins..I presume best I can??




Yes, desolder the pins. When I asked you to identify the components for E & D on the heat sinks on a previous post, you mentioned one was the SBT-150 and the other you could not see the numbers because they were faded. Start with the diode where the numbers are visible and then we'll work on identifying the other one. 




HairyKiore said:


> Re the diodes ...When I thought I could remove the heat sink I first had to loosen the screws holding the diodes to the heat sink ..One screw came completely out and the diode moved breaking the seal of the white silicon...I have put the screw back in and loosely tightened it..Hk



Good, re-tighten the screws the silicon grease will retake its form.


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## murihikukid

Hi..I am 99.9% sure that on the second there are no numbers. I got a real good look at it out in the sun a few days ago ...I can understand the testing procedure you set out ..but My problem is I do not understand what you actually mean by de soldering the SBT-150 ...wont the leads still make a contact unless I can get every bit of solder sucked up... Of course I can try if thats what you want me to do ....also I can only do a test under the board and not on the component side...Hk


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## octaneman

Remove all the solder off the pins there has to be no contact to the board, once the solder is removed there wont be anything around to obscure your readings. If there is even the slightest solder contact between component and board your readings will fluctuate and this is what we don't want.


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## murihikukid

Again I seem to have an equipment problem...My 25w soldering bolt does not look like melting the solder on the pins yet it easily melts solder purchased from the electronic shop...Would the small hobby soldering bolt be the problem or could it be the solder used on the board...and what is the solution here..Thanks Hk


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## murihikukid

Hi ..I have had another go and being honest its impossible...I have never had this problem de soldering in electronic projects and I am really concerned about the amount of time I had to apply the iron to the lead and even then it hardly made a mark so desoldering with my solder sucker or braid with this iron is out of the question...I also wonder if the circuit board has something sprayed on it..but no doubt you can inform me on what I can do..Thanks Hk


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## octaneman

There's nothing special on the board that will prevent you from desoldering components, your problem is your 25W iron doesn't give enough heat. 
A 50W soldering iron is needed for a job like this along with an adjustable heat range selector. It isn't really that necessary to have a selector knob but the selector comes in handy when working with smd's ( surface mount devices) as of right now your 25W is way to small you will need to get yourself a better iron. 


This is what I use for all my electronic jobs. 

http://www.testequipmentdepot.com/weller/pdf/wes51_data.pdf


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## murihikukid

Yes..I am afraid that a soldering station for me is simply out of the question ..unless I come across a used unit at a good price ...I am prepared to buy a 60 to 80W Soldering bolt and will look around town tomorrow.. but will it Help?? HK


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## octaneman

HairyKiore said:


> Yes..I am afraid that a soldering station for me is simply out of the question ..unless I come across a used unit at a good price ...I am prepared to buy a 60 to 80W Soldering bolt and will look around town tomorrow.. but will it Help?? HK




Yes it would, you need a base minimum of 50W because you want the iron to maintain heat when you are desoldering multiple pins. When you are out there buying your new iron, get yourself some soldering flux with a brush to apply it (pipe flux will do just fine) it will be of tremendous help when you are soldering & desoldering stubborn joins, your work will go faster and look professional I'll show you how and when to apply it.


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## murihikukid

Hi There is this 60watt one but strangely the seller says it should not be used for soldering smaller components or PCBs. ...Hk

60 Watt Soldering Iron DSE NEW | Trade Me


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## octaneman

Soldering smaller components do not need allot of heat so its is a little different, 50W is perfect for the job you want to do.


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## murihikukid

I have biked round all the electronic and hardware shops in the city..it seems that 25,40,60 and 80 are the range that everybody seems to have....At one electronic shop I was shown a soldering iron that I think was 25W but it has a "turbo" boost button that will boost it up to 100w for apparantly a few seconds...They said it was very popular but that is probably sales talk...Hk


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## octaneman

The best advice I can give regarding the iron issue is go to an electronics store where they sell components (resistors, capacitors, IC's ) ask them what is the most popular iron they sell for professionals, hobbyists etc.. you will be more informed on the selection of a quality iron.


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## murihikukid

soldering irons | Trade Me
Its a pity ..these appear to be good irons but they are 24v and going by the photos, they are part of a soldering station and the controling unit is missing...


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## octaneman

Here's one just like mine at a fabulous price. 

WELLER WES51 Analog Soldering Station with pencil Iron and Stand solder sodering | eBay

You will need a step down transformer *not an adapter* to convert the voltages from NZ voltages to US which I'm sure you can find.


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## murihikukid

Yes I wonder if Weller are available here ...The problem is that unless I can use Paypal... I would have to buy American money via my bank and there is a substantial bank charge for this ,there is exchange rates and finally a $47.50 shipping charge which to me is ridiculous ..When these are all combined together its not a realistic proposition ....I do have a good stepdown transformer to US ..Today I will check a couple of wholesalers ?? One never knows they may have one at wholesale price...I have seen soldering stations for sale over the years but of course when one wants one they are just not appearing...
The electronic shop guy whom I get on pretty well with was very enthuisiastic about the Iron with the Turbo button that increases the heat but there is no free trial??? But if I want to move forward I have to get something until I can find a soldering station....and he warned me that at the end of the day getting any components may be my biggest problem....


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## octaneman

HairyKiore said:


> Yes I wonder if Weller are available here ...The problem is that unless I can use Paypal... I would have to buy American money via my bank and there is a substantial bank charge for this ,there is exchange rates and finally a $47.50 shipping charge which to me is ridiculous ..When these are all combined together its not a realistic proposition ....I do have a good stepdown transformer to US ..Today I will check a couple of wholesalers ?? One never knows they may have one at wholesale price...I have seen soldering stations for sale over the years but of course when one wants one they are just not appearing...
> The electronic shop guy whom I get on pretty well with was very enthuisiastic about the Iron with the Turbo button that increases the heat but there is no free trial??? But if I want to move forward I have to get something until I can find a soldering station....and he warned me that at the end of the day getting any components may be my biggest problem....




I'm sure you'll find one somewhere down the line.


keep us informed of your progress.


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## murihikukid

Hi.. We do have an Australasian version of a Radio Shack ...So I have attached jpgs from their catalog of two soldering bolts and two stations listed with prices etc..Being in the twilight of life I really do not want to go too expensive as I may only use the tool once???.... so just wondered if you have a comment on any of these.... 
I do have a friend in NCarolina ...now I am basicly re-activating my PayPal account ( and if he is willing ) to get any Ebay item sent to him so as he could forward to me .....this could be another option but this could be a rather lengthly exercise so at the end of the day probably not worth it...Hk


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## octaneman

I can understand that you don't want to go overboard with the soldering stations it has to be used extensively for it to pay itself off. For the time being I'd go with the turbo soldering iron, it has the temp range you need for the job at hand. Before you buy it ask if it can be used professionally and what type of warranty it has just in case it turns out to be a lemon.


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## murihikukid

Ok thanks...will get it tomorrow ...If I ask if it can be used professionally I will probably we told "it depends on who is holding it" ...I am sure they will give me some sort if warranty being a local shop ..which I presume has a license or franchaise to sell this Companies products in the city...Hk


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## murihikukid

OK...I am not having any success ...I have bought the soldering bolt but I cannot desolder the leads either by my solder sucker or braid ..i have used the sucker before with success on other projects but this time I just cannot get any solder sucked up ..I am really concerned about overheating the components ...and to be honest I really question what I am doing ...in my estimation looking at the board via my magnifying headband ..there is no way I can get the solder removed to enable the leads to have no contact with the board..I have looked at the de-soldering tips on Google and taken these on board .. To be honest where I stand there is only one way to get the readings that you require and that is to somehow remove 
each SBT-150...test and put back on the board ...Hk


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## octaneman

HairyKiore said:


> OK...I am not having any success ...I have bought the soldering bolt but I cannot desolder the leads either by my solder sucker or braid ..i have used the sucker before with success on other projects but this time I just cannot get any solder sucked up ..I am really concerned about overheating the components ...and to be honest I really question what I am doing ...in my estimation looking at the board via my magnifying headband ..there is no way I can get the solder removed to enable the leads to have no contact with the board..I have looked at the de-soldering tips on Google and taken these on board .. To be honest where I stand there is only one way to get the readings that you require and that is to somehow remove
> each SBT-150...test and put back on the board ...Hk



Which iron did you get ? 130W is more than enough to remove solder.
I hope you are not attempting to remove the heat sink, we need the heat sink intact the only pins you should be working on is on the SBT-150. 

To get the joints to heat faster tin your tip a bit and then apply a little flux on the joints and to the braid then use the braid around the joint.


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## murihikukid

Hi I got the 130V one...But I am just using the Turbo boost on it sparingly as it was melting the solder with very little use of the turbo ..NO!! Its not the heat sink ..its the pins on the SBT-150's...as yet I have not got the soldering flux ...I will try later today ...Now I do know what the leads should look like once the solder is sucked up whatever ..I have never used braid before ...I wonder if I apply a little fluxed solder on the braid and joint if the braid will soak up the solder..or I wonder if I put a spot of solder on the joint to build it up and then use the sucker ..it may suck it all up as it will be better able to do it?? Hk


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## murihikukid

OK..the blob of solder did the trick and I used the sucker....I then thought if I used continuity on my Multimeter with one lead on the track and one on the lead it would indicate if the lead had been desoldered properly ...Although the leads are moving freely where they go through the board I did get continuity on a couple of leads but I am preuming this does not actually indicate that the lead has been desoldered ...its in the middle of the night and I am working in the bathroom?? or else I would take a photo of my desoldering effort and attach it....I am wondering if there is a final technique one can use or should I wait till when the sun comes up and take a photo..I certainly have achieved what I take as de-soldering ....HK


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## murihikukid

Hi Heres a photo ..best I could do from four tries... Hk


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## octaneman

HK,


The turbo is there to be pressed constantly until maximum temperature is achieved to melt the solder. Without touching the board press the turbo button in your hand until the iron heats up extremely well, apply a little solder to the tip and then place it on the joint the temperature will slightly decrease as you apply it to the joint this is normal. You should see the joint solder liquefy and then you can apply the solder sucker or braid.


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## murihikukid

Yes..thats basicly what I did...I really do not know how I could do better ..I do not know if even using braid would get it better..My photo is not good ..I could use an eye magnifyer and get a better visual on each lead in fact I think thats best and if I can see all leads are free ....I will move on and do the tests you required in an earlier post.. Cheers Hk


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## murihikukid

Just done the tests and reread your post and realised I have only done half of what you requested???? Will go back outside and do it properly..Hk


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## murihikukid

OK..I am already starting to feel like a technician!!!!!! The pins clearly look nicely desoldered but going by your earlier post I doubt if these readings will thrill you....
D102
Left to centre .MM set to continuity = no sound but meter reads .341

Right to centre .MM set to continuity = no sound but meter reads .341

D103
Left to centre .MM set to continuity = no sound but meter reads .191

Right to centre .MM set to continuity = no sound but meter reads .192

Now I just rechecked everything and D102 gave me a reading slightly different ..instead of .341 it was .344......Same with D103 I got .196 and .197

Now the part I originally missed...When I reversed the leads all the readings came up 1. on the multi meter
I hope these readings help.. Hk


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## octaneman

Way to go HK ! Actually the readings tell me that the D102, D103 of the SBT-150 with power off is good ! Nicely done ! How do we know that they are good ? Simple, Victor sets your multimeter's readings of infinity is designated as 1 instead of OL so when you reversed your leads there was no continuity so the diodes are conducting in one direction as they should be. 

Quick lesson; What you are seeing on the meter are actaully voltage readings when its set to continuity or any other setting. In reality All digital and analogue meters are designed to emit a very small current to the components under test. 

Now for the next step; 

Leave the SBT-150 desolderd for now do not solder it on the board just yet it is isolated from the rest of the board because now you will test all the capacitors to the right side of the diodes which have the CE letters assigned to then on your board. 

You will notice that the capacitors are polarized (positive, negative) On the capacitors you will see their specifications written on them by the manufacturer they are in voltage ratings on one side and in capacitance ratings on the other which is in microfarads. For example 25v 450uf 

The accepted method in testing capacitors is with a capacitor meter or a ESR meter. Since you don't have any of those you will be using the meter to test them in 2 scales. 1) Resistance 2)Continuity 

To test capacitors with your DMM set your meter on the 200M scale place your leads to their respective polarity on the capacitor. What you will see on the meter readings is the capacitors charge rate. The readings will gradually increase incrementally as it charges this means that the capacitor is charging. When you reverse your leads on the capacitor the readings will be gradually discharging decreasing incrementally. This indicates that the capacitor's charge rate is good. 

The second test is to set your meter to continuity, your meter should show readings on positive polarity and when you reverse your leads. 


A bad capacitor will show signs in 3 ways: 

1) On the 200M scale The charge rate on the capacitor will rise and fall very rapidly instead of incrementally. 

2) On the continuity setting your meter will show infinity on both directions. 

3) Capacitors will have visible signs of damage such as bloating or leaking. 


This particular phase will take you a bit of time to do because there are quite a few capacitors on the board. To make your job easier an quicker, locate each capacitor from the top side and then using your fingers find the pins under the board use a sharpie marker to mark the positive and negative pins on the board. In this way when you go to test them you will know which pins correspond to the capacitor on top


If you suspect one capacitor is bad mark it down on paper and its location so you don't get confused with the rest of the board.


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## octaneman

Addendum:

My appologies I should have seen this earlier. 

Your meter's maximum resistance scale is 20M set your meter to the 200k scale to test the capacitors ok ?


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## murihikukid

Ok..One question re 200m on Multimeter ...I have circled two ...is it the one on the brown band to the left or the white band to the right....also I have attached a picture with the capacitors marked...There is two small capacitors as well as the large one up near the AC Power socket.. are these to be checked also ....
Do you require the uF of each of the capacitors .....I certainly do not think there is any way I can read the markings on CapacitorA...

I have seen "Bad" capacitors in the past on a PC motherboard so have a good idea on what they look like...none of these look visually bad...

Once I know the DMM setting to use I will get into it...Thanks Hk

PS>SORRY I never saw your ADDENDUM TIL TOO LATE


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## octaneman

All capacitors will be checked no exceptions. 


On your meter under the scale you see the letters A. On the right A has a sign wave the left has a parallel bar. The right A is A/C current the left A D/C current. 

The A indicates that all readings on that side of the meter are in Amps. The scale you circled on the right is identified as 200 milliamp range for A/C current. The A on the bottom left with the parallel bars is also in the Amperes range but for D/C current which is identified as 200 milliamp D/C current. 

This is for measuring current *only*

The setting we want to use is the resistance scale where you see the 200k just above the continuity setting for the capacitors.


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## murihikukid

Right I am just having a try on Capacitor A with my DMM set to 200K to see what happens?? When I put the leads on, it starts at minus 09.0 jumps to 01.6 and jumps up to 02.6 in increments ..reversing the leads I get a result basicly the same but the first reading I get is minus 09.2 then it jumps to 01.5 and jumps up in increment readings to 02.6.....

Now the Continuity Test...Is this paragraph you posted actually finished
>>>The second test is to set your meter to continuity, your meter should show readings on positive polarity and when you reverse your leads. >>>>>>

I have put the DMM on Continuity and taken a reading and the reading just keeps on climbing...when I reverse the leads the same happens ....Is this what it should do and do you want me to try and get a start and end to the meter reading as it rises....Thanks Hk

PS ..I have taken in your note on AC and DC readings on my DMM..Thanks


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## octaneman

So far the test on capacitor A tells me that its charging and discharging incrementally this is what you want to see on the meter. 

Since the capacitors are soldered to the board there is that slight leakage through the board which is acceptable to a limit, so the continuity setting should act like the resistance setting. 

Note: On high voltage capacitors like the one next to the A/C socket your meter may not give out readings because of high voltage needed to charge it. The way to test those large capacitors is with the power on test which will come later in your diagnostics.


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## murihikukid

Jingling Soldering station (with spare tip) | Trade Me

A day too late for me..Looks a tidy unit..and if you think its worth $35 I will put in a bid...Hk


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## murihikukid

OK...Capacitor B and I am getting a reading that with the leads on the correct polarity it starts minus 09.0 moves instantly into a positive reading and moves up in increments...reversing the polarity I get minus 03.0 or 04.0 and it goes into a positve reading upwards in increments..
With the continuity setting I place the leads at the correct polarity it just starts round .26 and rises ...Reverse the leads it rises but stops at .556....This is a terrible job trying to catch the numbers on the meter as well as trying to ensure the leads remain in contact and everytime I do it I seem to get a different reading..Hk


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## murihikukid

I always read Positive to red lead first.....
Capacitor C basicly same as B.....But to be honest I do not know what I am looking for ..I am trying to read D and its starting off with a reading of minus 18.0 ..Change the polarity and its going up from 38.0....Continuity reads 1.1 and keeps rising ..reverse the leads black to + and I get .45 to .518
E is going from minus 28.0 up to zero and keeps going ...reverse the leads and its rising from 28.0 up.....Continuity reads 1.1 and keeps rising ..reverse the leads black to + and I get .45 to .518
F reads minus 32.0 and keeps going to plus still rising...Reverse the leads and I have 78.0 and rising....Continuity reads 1.0 and rises ..reverse the leads and starts .48 rises to .518
Now in the photo a couple of posts back is G out to the side a capacitor? Hk


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## octaneman

Hk, 

When you place your leads on the capacitor the capacitor will charge up but it also keeps the charge. When you take your readings the meter will indicate the level at which the capacitor is charged when you reverse your leads therefore you get different readings. To set the charge state to 0 short out the positive and negative pins on the capacitor with a resistor (any will do). As long as the charge rate is incremental both ways the capacitor passes the test.


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## octaneman

HairyKiore said:


> Jingling Soldering station (with spare tip) | Trade Me
> 
> A day too late for me..Looks a tidy unit..and if you think its worth $35 I will put in a bid...Hk




I'd pick it up for sure, the price for the unit is very reasonable and with an adjustable heat settings with spare tip is a great deal.


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## murihikukid

I have put in a bid for the soldering station so I will see what happens ..
Re the Capacitors ...Will I start again...Will I take a resistance reading Postive to positive and then short it out and then take a Positive to Negative reading?
I presume Incremental Readings means the readings jump from for example 1.00,1.10,1.20 etc up...


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## murihikukid

Thank Goodness its Fine outside..I have redone them all and shorted out between tries BUT I still get a different start figure ..It comes up and moves so quickly but this is the best I can do..I will point out when I see an irregularity
These are the resistance figures..

Cap A
+ to + = -07.6 to 02.7
+ to - = -07.8 to 02.6

Cap B
+ to + = -08.2 to 10.00 and still rising
+ to - = -0.46 to 10.00 and still rising

Cap C
+ to + = -08.9 to 10.00 and still rising
+ to - = -02.9 to 10.00 and still rising

Cap D
+ to + = -09.0 to 10.00 and still rising
+ to - = -04.8 to 10.00 and still rising

Cap E
+ to + = -10.6 to 10.00 and still rising
+ to - = -08.6 to 10.00 and still rising

Cap F
+ to + = -10.4 to 10.00 and still rising
+ to - = -05.0 to 10.00 and still rising

Cap G
+ to + = -11.9 to 10.00 and still rising
+ to - = -11.3 to 10.00 and still rising

These are all the caps at the pin end of the board ..I never saw any irregularities when I took the readings...but writing them out I just wonder if I have miswritten the reading on ...Cap B + to - = -0.46 to 10.00 and still rising ..It could be............
+ to - = -04.6 to 10.00 and still rising...........But I am sure if you see anything you will tell me to recheck ....

Now the two small Capacitors at the AC Socket end (photo attached) these I thought raised suspicion ...especially in the continuity tests...BUT
heres the resistance readings

Cap H
+ to + = -05.6 to 100.00 and still rising
+ to - = -02.9 to 100.00 and still rising

Cap I
+ to + = -07.2 to 100.00 and still rising
+ to - = -07.0 to 100.00 and still rising

Now heres all
the continuity readings...

Cap A
+ to + = .388 upwards
+ to - = .222 upwards

Cap B
+ to + = .222 upwards
+ to - = .200 upwards

Cap C
+ to + = .325 upwards
+ to - = .300 upwards

Cap D
+ to + = .090 upwards
+ to - = .224 upwards ****

Cap E
+ to + = .269 upwards
+ to - = .120 upwards ****

Cap F
+ to + = .135 upwards
+ to - = .238 up to .505 

Cap G
+ to + = .283 upwards
+ to - = .166 up to .502

Now to Cap H and I where the readings were of a different pattern

Cap H
+ to + = 1.6 then immediately to 1
+ to - = .501 ..thats it no upward increments

Cap I
+ to + = 1.400 then to 1.547 
+ to - = .510 then to .561

On Cap D and E on reverse polarity marked *****I did get an initial continuity buzz from my DMM ..it soon stopped and I do not think I was touching any nearby tracks just the Cap leads..So whether this signals anything I certainly would not know..
Cap F and G on reverse polarity I got a ceiling reading of .502 to .505

I sincerely hope this is all of help ...Hk


----------



## octaneman

HK,

All of the these readings from positive to negative are good: 

Cap A
+ to - = .222 upwards

Cap B
+ to - = .200 upwards

Cap C
+ to - = .300 upwards

Cap D
+ to - = .224 upwards

Cap E
+ to - = .120 upwards 

Cap F
+ to - = .238 up to .505 

Cap G
+ to - = .166 up to .502

Cap I
+ to - = .510 then to .561





* Cap H * <------------ ( suspect )
+ to + = 1.6 then immediately to 1
+ to - = .501 ..thats it no upward increments




I'm trying to understand your positive to positive readings; Are you taking the black lead of your meter to the positive of the capacitor and red lead of the meter to negative of the capacitor ? (discharging) because this is what you're supposed to do. 

.



Note : * Cap H is suspect.*


----------



## octaneman

Hk,

Let me show you the charging state of the capacitor. The meter is set to 200k ohms 

I'm testing a 50v 330 uf capacitor. 

The first 2 pictures charging state. 

positive lead of meter to positive of capacitor, negative lead of meter to negative of capacitor. 

meter reading 20.9 and rising (pic 0000) 
As high as 64.7 (pic 0008) 



Second set of pictures is the discharging state of the capacitor. 

negative lead of meter to positive of the capacitor, positive lead of meter to negative of the capacitor. 

meter readings 17.7 and dropping (pic 0003)
as low as 2.2 pic (0002)


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## murihikukid

+ to +....I put the red lead to the positive on the cap...+ to - I put the red lead to the negative of the cap. Don't say that I have got my colours mixed up and that Black is the positive lead on a DMM .Hk


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## octaneman

The + to - is the reverse polarity of your leads ..correct ?



Your posting of + to - as reverse polarity changes everything from my initial analysis from my earlier post. Your readings should go down not up.


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## murihikukid

I think so.. I made sure I knew what was Positive on the cap....I put my red lead on it and my black lead on the negative and took that as + to +......I then changed the leads over putting the black lead of the DMM to the Positive and the Red lead to the negative...Hk


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## octaneman

HairyKiore said:


> I think so.. I made sure I knew what was Positive on the cap....I put my red lead on it and my black lead on the negative and took that as + to +......I then changed the leads over putting the black lead of the DMM to the Positive and the Red lead to the negative...Hk


When you take your readings in the future refer the + to - to its respective polarity on the meter so there is no confusion. 


When you are taking reverse polarity readings mark them as - to +


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## murihikukid

I am confused also...I thought that my Red lead to the positive side of the cap and my black lead to the negative side of the cap charged it up and if I reversed the leads IE black lead to the positive of the cap and red lead to the negative side of the cap discharged it ...My readings got no discharge so I must be doing something wrong...
Next time I will refer to red lead and black lead of the DMM to whatever polarity of the cap I apply them to...hk


----------



## octaneman

HairyKiore said:


> .I thought that my Red lead to the positive side of the cap and my black lead to the negative side of the cap charged it up and if I reversed the leads IE black lead to the positive of the cap and red lead to the negative side of the cap discharged it.




Thats exacally whats supposed to happen. :thumb:

Just make sure your meter is set to 200k ohms


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## murihikukid

The DMM was set to 200K...So what do I do now? Wait a minute I was shorting out the Cap with a resistor between tests ..so wouldn't that discharge it before I put the leads on to get a reverse reading ...Just a thought???....Hk


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## octaneman

Start with one capacitor ( doesn't matter which) and and place your leads in the positive polarity positive lead to the positive of capacitor negative lead to the negative of capacitor. leave your leads on for 2 seconds so it can charge and take your readings then mark them as + to - 


Reverse your leads and you should see the capacitor discharge and you mark those as - to +.


----------



## octaneman

HairyKiore said:


> The DMM was set to 200K...So what do I do now? Wait a minute I was shorting out the Cap with a resistor between tests ..so wouldn't that discharge it before I put the leads on to get a reverse reading ...Just a thought???....Hk





Oh boy , there's your mistake. You short out the capacitor *before* you do the test. You do *not* short out the capacitor when you reverse your leads. You need the charge in it to see if it discharges through the meter. 


What you were doing was discharging the capacitor between polarity tests effectively bringing the charge to 0. Thats why your meter was always rising when you reversed your leads.


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## murihikukid

Yes I realise my mistake...I will try and do it all again tomorrow...Hk


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## murihikukid

OK I am back..It seems my problem is my inexperience at reading a DMM.....I put my Red lead to the Positive of the capacator and immediately I get an initial minus reading which immediately goes to a plus and rises in increments til I stop the reading at 10.00....Now I change the leads IE Black lead to Positive/Red to Negative ....I get a minus reading for example 0.47 and it goes incrementally downwards/backwards whatever (0.46,0.45,0.45,0.44 etc) till it reaches zero and the DMM goes into a plus reading (00.01,00.02,00.03 etc )and if I keep holding the leads on the Capacitor it will just keep on rising ...

Is this what it should do?? What I should see ?...Hk


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## murihikukid

Should I ignore the initial minus reading that appears when I put my Red lead to the Positive of the capacator....and the more I read your post it seems to me that what you describe does not happen when I discharge the cap with my black lead on the positive of it....Hk


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## octaneman

HairyKiore said:


> OK I am back..It seems my problem is my inexperience at reading a DMM.....I put my Red lead to the Positive of the capacator and immediately I get an initial minus reading which immediately goes to a plus and rises in increments til I stop the reading at 10.00....Now I change the leads IE Black lead to Positive/Red to Negative ....I get a minus reading for example 0.47 and it goes incrementally downwards/backwards whatever (0.46,0.45,0.45,0.44 etc) till it reaches zero and the DMM goes into a plus reading (00.01,00.02,00.03 etc )and if I keep holding the leads on the Capacitor it will just keep on rising ...
> 
> Is this what it should do?? What I should see ?...Hk




Bravo ! You did it !
That is exacally what your readings should be on the meter when its charging /discharging, when you reverse your leads your meter shows you with a minus sign that you have reversed polarity and its discharging incrementally. 

When the capacitor reaches 0 it will charge again this is normal, the initial minus sign when you placed your meter is that the capacitor was totally empty this is normal also. 

Good job Hk !


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## murihikukid

Hi Just Explaining why my lack of reply ...I had to go to the hospital and have a back tooth removed and I have been in real pain ..Hopefully tomorrow I will be be back into it again ..Hk


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## murihikukid

OK..I am feeling slightly better so went outside and did further checks..Now this DMM when I check each Cap Red Lead to Positive on Cap always gives me ONE initial minus reading before moving into upwards positive incremental readings..Whether right or wrong I am basicly ignoring this initial minus reading and regard it as 0 ??........So I can confirm that Caps B,C,D,E,F and G read exactly as you advised in your previous post ...My problem is with caps A,H and I.....

Cap A...

Red lead to Cap Positive = -08.8 to 02.7 ..When I put the leads on there is the one minus reading... Then reading does go up in increments but tops out at 02.7
Black Lead to Cap Negative = -08.0 to 02.6 ....As I see it there is no real difference between the two readings ..they both are the same so that is confusing to me....

Cap H..

Red Lead to Cap Positive ...starts at an initial minus then raises in jumps like this 10.0,20.0,40.0,50.0 etc up to 197.0 then to 1......(is that infinity?) 
I then reverse leads 
Black Lead to Positive Cap ...-47.5,-30.0,-20.0,-10.0 then into positive ...The increments go that fast I cannot get readings exact....but the Capacitor certainly charges up in significant larger steps than the other caps ..and finishes at 1 .
with the black lead to positive I get a minus reading of around minus 45.00 to minus 47.00 which goes down in aprox four incremental minus readings till it starts giving a positive reading ... 

Now Finally Cap I
Like Cap H... Cap I Red Lead to Cap Positive ...starts at an initial minus then raises in jumps like this 10.0,20.0,40.0,50.0 etc up to 197.0 then to 1......(is that infinity?) 

I then reverse leads but at the most I get one or maybe two "incremental" minus readings before its into positive ....Gee I wish DMM would give a electronic readout after a test??? Its so fast I just cannot read it...

So I will just wait for feedback.. Hk


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## murihikukid

I could perhaps set up a webcam that would video my tests ....then slow the resultant video down???? Hk


----------



## octaneman

Hk, 

You did great ! caps H,& I read perfectly OK , remember that there is a slight leakage through the trace that is acceptable because the capacitors are still soldered to the board. The charge rate depends on the size of the capacitor, the smaller the capacitor the quicker charge /discharge rate will be. When capacitors fully charge they reach their saturation point where it won't accept more charge, its like you putting in gas inside your car and the gas gage needle points past the full mark to overfull so unlike your gas gage the meter cant go any further which will read infinity (1 on your meter). 

Caps H & I will be looked more carefully during the power on test because they are in close proximity to the transformer. The transformer is what we are going to test next. 

Are you OK with the cap tests so far ?

If you are still confused plz let me know.


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## murihikukid

Yes..I am slowly learning ..I did have a brand new Logitech HD Pro Webcam C910 bought on Boxing day so I finally just unwrapped it and installed the software etc...It now means I can set it up to record any tests I do with my DMM ...so I can accurately see what the DMM screen is showing by slowing the video capture down and if need be do an image sequence which would enable me to pick out certain frames and post them ...So this may come in very handy in the future..I do see one can post Rar and Zip files so I presume it is possible to post small video clips within a Rar or Zip file..
As for the Cap Tests done so far ..B to G were excellent as I could clearly see the charge and discharge ...A did confuse me as I expected similar to B>G...
Re H and I the readings flashed so quickly on the DMM it was difficult to distinguish the readings but clearly both were being charged and on reversing the leads ..discharging ....
I certainly made the right choice in asking you about the DMM to buy...I could have ended up no better off but this unit I would say is a great semi professional unit....Also I purchased the Soldering Station that I sent the link for in a previous post ...$44 ....with a $10 shipping cost so thats $55 all up and no doubt worth that and it will be an asset in the future ...I now await further instructions when you are ready...Thanks Hk


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## murihikukid

I Just did a couple of experiments...I really do not know why I never thought of it before ...I could have sent you a small video clip showing you exactly what the DMM was reading ...I just did 60 seconds of video w Audio and it saved to a WMV file with a 9.5MB size ..I presume I can probably reformat to flv or mp4 and get a reasonably sized clip RARed or ZIPPed at under the 5MB limit..Its just a means of communication that may come in handy...Hk


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## octaneman

Fabulous ! The web cam will definitely come in handy when we do the power on tests. 

Now for the next step: The Transformer. 


As you know the transformer is what supplies power to the entire board, they can bring up the voltage or bring it down or in some cases keep it steady. The transformer has 2 sides, one is called the primary the other the secondary. The primary side is the side that is connected to the A/C of your wall voltage the secondary is the output. The transformer does *not* regulate or rectify voltage ( changing A/C to D/C)it only *transfers* magnetic energy from side to another via its coils. So to keep it simple think of it this way; Whatever goes in one side comes out the other. For example: When A/C voltage is on the primary side on the secondary output side will also be A/C voltage. The same thing applies to the transformer when D/C voltage is applied. 

Now, as I said earlier the transformer can bring the voltage up this is called a step up transformer. When it brings down it called a step down transformer. The voltage on any given transformer will depend on how many *turns of wire* is wound on its coils this is determined by the manufacturer. The more turns the coils have the more resistance it has which will show up on your meter. 

The rule of thumb is on step down transformers low resistance on the primary side, high resistance on the secondary side. 

On your particular transformer the input (primary side) and output ( secondary side) has multiple pins that gives various voltages throughout the board. How do we know this ? Simple, we already know that on the 8 pin connector we need low voltages such as the +5 standby and the +13v, so we determine that our transformer is a step down transformer which must give out these voltages. The input side of the transformer is *always* wall voltage, so you must take extreme safety precautions not to touch anything on the primary side when the board is powered up. 




Testing the transformer is done in one of 2 ways; 1) Resistance 2) Voltage. The most accurate test will be the voltage test, it will leave no doubt that it works or not. 

Coil test; Start with one side of the coils. Set the meter to continuity connect your leads together make sure you get a tone. Connect your leads to any pins pairs on the primary side you should get continuity ( low resistance reading). If you don't get a tone the windings are shorted out. 

On the secondary side you will perform the same continuity test on all pin pairs, your meter should give out a tone but you will see higher resistance readings. If not mark the pin pairs so when we do the power on test we'll know if voltage comes out.


The second test is the voltage test: This is done with power on, we'll do the power on test later once were done with power off.


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## murihikukid

Hi...I am not sure exactly what you want me to check so I have attached a Jpg which has the top and underneath the section of the circuit board relating to the AC supply ..Its not a mirror but the left on the left image relates to the the left of the image beside it....I have marked by a straight blue line where I have done a continuity test so far....Can you tell by the jpg where else you want me to check and if possible mark the jpg and attach ..Thanks Hk


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## octaneman

Hk, 

I've marked the pins of the transformer I want you to check, as you can see I've marked them primary and secondary. 

The primary side is the wall A/C which I see on the underside of the board are the 2 farthest pins of the transformer. Place your leads there on continuity and you should get a tone. 

The 2 center pins of the transformer's primary side go to the photo-coupler which when you place your meter leads you should not get a tone. 



On the secondary side all the pins should have continuity in relation to one another starting from the center pins moving outward when you place your leads.


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## murihikukid

Hi...For a while I got completely lost ...Was the attached photo oringinally on your second last post....That has just alerted me to the fact that I misidentified the transformer as another component$%^&?? Must be the pain in my head and mouth I am still experiencing ...So now hopefully, I think I am on track...
The Primary Pins have no continuity...
The 5 secondary pins have all got continuity..So maybe this result tells a story.. Hk


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## octaneman

No readings at all on the primary?!?!.. Impossible. Re-do the primary pins again, only this time scale up your meter until you get a reading. Post your results along with the scale at which your meter see's it. 

The secondary pins are all ok.


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## murihikukid

Hi I was going by tone....I get a reading of .527 with the black lead to the left pin and the red to the right pin but no tone... ...If the Red lead is put on the left pin as in your photo and the black on the right pin I get 1...so it depends on the polarity of the leads...I wonder if the battery is getting weak in the DMM..Hk


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## octaneman

Much better  The primary is OK. 


We're moving on the next test. The Diodes. 


In the photo I've circled 2 diodes. Like the SBT-150 they conduct one way only. The difference is you will have to desolder 1 leg of the diode to get an accurate reading. These types of diodes are marked with a grey band around it showing you its polarity. The band side is negative the other side is positive. 



Set your meter on the 200K scale. ( If you dont get a reading on the 200k scale move the knob to the 20M scale) Place your positive lead on the black side of the diode and and negative on the band side. You should get a reading one way but not the other just like the SBT-150. If you do get reading when your leads are reversed the diode needs to be replaced. 


FYI: The diode that is next to transformer should be where the +5v standby comes from.


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## murihikukid

OK..Both Diodes read as they should Black Lead to Gray Band end I get a reading of round 160.0....I did have problems with the diode to the right of your picture near the transformer..I initially got a reading both ways so I actually pulled one end free of the board with a pair of surgical pliers and then got a true reading....I looked at my desoldering and could have sworn it was properly done but with a reading on both ..evidently to me there still must have been contact so it was a good job I pulled the lead of the Diode ...It will be easily put back in...But going by your instructions both Diodes are OK..Thanks Hk


----------



## octaneman

Good job ! 


Now that the diodes are tested we're going to move on to the power on stage because we'll have to verify what we've done so far with the power off test. First and foremost you are going to re-solder all the components back on to the board like the SBT-150 and the diodes you just tested. 

What we are going to do is test the voltages that comes out of the transformer to the rest of the board. When you begin your power on test it is absolutely essential that you take every safety precautions to avoid injury to yourself. Remove any jewelry or anything on you that will conduct electricity, wear loose clothing and that you are well insulated. Remove any metallic objects and excess solder from your workbench where you have the board, you don't want any solder particles that will create unwanted connections on your board that will blow components. 

I cannot emphasize this more; SAFETY ! SAFETY ! SAFETY ! The main filter capacitor (next to the A/C plug) is very high voltage and it carries a charge even when the power cord is disconnected from the wall. Please be very careful where your meter settings are and how you place your leads on the board. If you have to take a break from your testing or you are calling it a day, always remove the power cord and discharge the main filter capacitor with a high value resistor in the 20M ohms range or more. *Do not use low value resistors to discharge the main filter capacitor you will burn your fingers or get zapped.*



Power on test.


Plug the board to the wall; Set your meter to 25 volts D/C scale and test the capacitors that are next to the 8 pin connector. Place your leads on the correct polarity of the capacitor and take your readings. Mark each reading down one of those capacitors is carrying our +5v standby. *The filter capacitor will be in the 160v range or more always reset your meter to proper scale when testing the large filter. Do not test filter capacitor on low scale or you will blow the meter fuse ! *


post back your results


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## murihikukid

Hi..I certainly want to get this right ...I will solder the diodes back to the board...BUT heres is my question ...We are now going to test the board with power on...It seems to me that this can only be done with the board by itself and not put back on the monitor chassis...I may also have to bike uptown and get a high value resistor...Its forecast to snow later???so winter is on its way....Hk


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## murihikukid

Oh Dear..What a job to get a resistor ?? Finally I have been advised by the local Electronic Services shop to solder 2 wires to a normal light bulb ?? instead of buying 2 x 10M Resistors from them at $2 each ..plus it saves me a bike ride in the rain...Hk


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## octaneman

HairyKiore said:


> Oh Dear..What a job to get a resistor ?? Finally I have been advised by the local Electronic Services shop to solder 2 wires to a normal light bulb ?? instead of buying 2 x 10M Resistors from them at $2 each ..plus it saves me a bike ride in the rain...Hk



Yup, thats the old school method I made one myself, you can use it as a fuse in t.v sets to troubleshoot where there's a short circuit blowing the fuses all the time. 

(saves a fortune in replacing them all the time too)


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## murihikukid

Hi..I have just soldered all the diodes etc and in the morning will search for some alligator clip wires that I know are somewhere to make up a discharge fitting...I still need verification re the power board and power on....Do I sit it upside down say on a towel on a table which will stop it moving and have beside me a clear paper plan on the pins of each capacitor (+ and - ) that I need to get readings from ...
Then when I have everything safely set up to my satisfaction do I plug power into the AC Socket?? and do the tests you require...Hk


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## murihikukid

Hi..Can you please confirm answers to my questions as I so not want to be working with power on unless I am 100% sure of what I am doing or how to do what you are asking..Thanks Hk


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## octaneman

You could use a towel under the work bench to prevent the board from moving its not a problem, just make sure the towel is clean and there's nothing on it that will conduct. Place the board upside down in a position where you can work best then take your readings. When you take the readings from the capacitors remember that each capacitor will read different voltages when you do them one at a time because of its voltage rating. For example: If the capacitor is rated 25v 300uf your meter set on D/C volts should read 25v anything less there's a problem. It is best that you mark each capacitor down on a piece of paper so when you take the readings you won't get confused.


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## murihikukid

OK..I was all set to start and realised that I am not 100% sure of the setting on the DMM to use....I think I have got it right but I do not like fooling around with live electricity....so have marked a photo of my DMM front....I am Sure I have put the blue circle on the DC readings ....but do I set it to 20 volts...Thanks Hk


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## octaneman

Yes, set it to 20V, but for added piece of mind look for the voltage ratings on the capacitors. There exists small capacitors in the 50V range on the board so don't be fooled by their size. For example in the pic you see how small the capacitor is but its voltage rating is 50V. Don't forget that large filter capacitors are rated 160V + and more *always* adjust your meter to the correct scale.


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## murihikukid

Hi..What Say if I desolder and take Cap A and B out to see what they are ....and put them back again...?? the heatsinks are so close they block the writing on them...I think I may have to remove another so it and the rest can be identified ...Hk


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## octaneman

Do whatever it takes to identify the voltage ratings on the caps.


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## murihikukid

oK..Thanks ..I am just going to bed so I will be back in a few hours...Hk


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## murihikukid

OK ...Part one capacitor Identification are marked in jpg attached..now to do the power on tests.. Hk


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## murihikukid

OK..Power On Tests ...
Capacitor A= 14.34
B= 5.03
C= 5.03
D= 17.65
E= 17.65
F= 17.65
G= 17.65
Please advise what next to check ..Do you want me to test the Main Filter Capacitor and is that DC or AC with a 20v or 200v DMM setting......thanks Hk


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## octaneman

Main filter capacitor is D/C set the meter at 200V.

The next test is the ripple test.

The ripple test will show us if any capacitors are leaking A/C. Set your meter to A/C voltage, probe each capacitor like you did before with the voltage test, only this time your meter should read 0.00. There should be no A/C coming out from the capacitors. 


Question: 


Which pins on the power board does the on/off switch hook up to the capacitor side or the other ?


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## octaneman

Hk, 

Addendum: 

I'll need you to remove the resistor fuse and the piece of tape you used as a buffer so I can see the fuse trace path. Please post a picture of the board as is but make sure that the surface mount fuse is still soldered on the board.


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## murihikukid

OK..will do cause I am up and running...Just done the main Capacitor and get a reading of 
04.1 with the DMM set at 200v DC...
Question:
Which pins on the power board does the on/off switch hook up to the capacitor side or the other ?
Sorry I do not understand what you mean here ..what on/off switch and regards picture required AS IS ...Is this under the board?? There has never been any fuse or any other part removed from the board....I will remove the resistor that bridged the fuse ,do the ripple tests and take a photo...if I can in the light in the bathroom..Hk
PS..I presume I set the DMM at 20v AC to do the ripple test.


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## octaneman

Main cap is ok. 




HairyKiore said:


> what on/off switch and regards picture required AS IS
> Is this under the board ?


I'm refering to is the switch that turns the screen on. Is it on the video board that plugs into the power board's 8 pin connector ?


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## murihikukid

Ok..A photo is impossible until daylight? Re ripple test,power on....heres what I get with the DMM set to 20V AC (it takes a lot for the DMM to settle down on each reading so I presume this is normal.....??)

Capacitor A = 0.02
B = 0.01
C = 0.01
D = 0.02
E = 0.02
F = 0.02
G = 0.02
Please advise If I have done it right..Thanks Hk


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## murihikukid

I'm refering to is the switch that turns the screen on. Is it on the video board that plugs into the power board's 8 pin connector ?

No...I do not think so ..I see no switch? So I have attached photo..and Do I do a ripple test on the Main Filter Cap..Hk


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## octaneman

HairyKiore said:


> Do I do a ripple test on the Main Filter Cap.


Yes . 


I've circled a switch on the video board. Is this the switch to turn your screen on ?


----------



## octaneman

HairyKiore said:


> Ok..A photo is impossible until daylight? Re ripple test,power on....heres what I get with the DMM set to 20V AC (it takes a lot for the DMM to settle down on each reading so I presume this is normal.....??)
> 
> Capacitor A = 0.02
> B = 0.01
> C = 0.01
> D = 0.02
> E = 0.02
> F = 0.02
> G = 0.02
> Please advise If I have done it right..Thanks Hk



Good Job !
Readings are normal. The capacitors are not leaking A/C


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## murihikukid

Main Cap gradually settles down to 0.00.....Is it the charge within the caps that makes a reading take the times it does to settle down to 0.00...I presume the others may have come down to 0.00 if I had stayed another 5 minutes on each??
Re the Switch ..unless its an electronic switch..this is just like a normal electronic component to me....it certainly is not a manually operated switch..The logic board itself is still on the chassis and I was able to rub my little finger under it where the component you circled is and it feels absolutely flat IE there is nothing even to indicate a solder joint ....I tryed to read any markings on it but it has the spot of Blue Paint on the top so any readings if it has any are impossible to see.
Re photos ..Unfortunately its 3.46am here and although its forecast to be a find day later its probably another 8-9 hours before I can take a photo ... Hk


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## murihikukid

By the way ..The soldering station has arrived ...I must open the box and inspect it later in the day...Hk


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## octaneman

The soldering station will come in handy in the next phase of the diagnostic. When you are ready we will test the inverter transformer. 

The inverter transformer is the rectangular box with 4 pins on the top side of the power board.


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## murihikukid

Mmmm...I wonder if the inverter is what I originally mistook as a Transformer..as Circled?Hk


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## octaneman

Power down the board and discharge the main filter capacitor. 

I've markerd the inverter and the points where you will test it. The center pins are the primary and the two outer pins are the secondary. The testing procedure the same as the power transformer the only difference is it has to be desoldered and removed completely off the board. The reason is that its sensitive to the inverter drivers that are soldered underneath the board. 

Testing the inverter transformer:
Set your meter on continuity connect your leads together make sure you have a tone. Probe the primary pins your meter should read continuity. 
Probe the secondary and your meter should read continuity. 

The most important side of the inverter transformer is the secondary, if there is no continuity your inverter needs to be replaced.


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## murihikukid

OK..The secondary pins have a clear compound of some sort over the solder ..Hopefully you know what I am talking about but have attached photo...This no doubt will have to be removed...Can you please advise on how I do this.. thanks Hk


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## octaneman

Use the iron to melt the compound wipe the tip constantly to avoid build up it should come off fairly easy.


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## murihikukid

Thankyou...Hk


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## murihikukid

Ok..I am ready to test..Now there are 4 pins either side of the inverter..Do I use continuity on each side ...IE the two centre Primary pins ....the two outside secondary pins ....OR does across the inverter come into play .. I hope my attachment is adequate for what I mean.. Hk


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## octaneman

Truth be told some inverter transformer pins test *diagonally* not side to side like regular transformers. Test it both ways to be sure. One thing is certain; that the transformer primary and secondary *must* have continuity in order for it to work.


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## murihikukid

Ok..Heres what I have as per attachment..we have continuity tone across the centre Primary Pins...as depicted ...I have tryed diagonally etc but as marked is the only Continuity tone I get..
But the Secondary pins I get no continuity tone ....I do get a reading of .456 as marked otherwise all others are 1 ie..diagonally etc..
Hope this provides the answers.. Hk


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## octaneman

For the secondary do the test again this time set your meter to 2k ohm setting, on average it should be from 660 ohms to 1.4k ohms. 

Flip over the inverter in your hand you should see the windings, do any show signs of burn out ?

please post your findings.


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## murihikukid

Right..with DMM set to 2K ohm readings = .519 and .522
or set at 20K ohm reading = .51...
No sign of burning or heat see attached photos along with under board and fuse area...Its basicly now time to sleep???Hk


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## octaneman

The numbers on the secondary are nowhere near what they should be.

Looks like we found our culprit but we'll need to verify it.


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## octaneman

This is to verify the inverter transformer.

In the picture you will see 2 arrows in yellow pointing down. This is the primary side of the inverter. Set your meter to the lowest ohm scale and place your leads to the two points where I've marked 1 (sort of). 

Your meter readings should be extremely low somewhere around 0.2 ohms. 


The secondary I've marked another 2 arrows in yellow pointing up,Its marked as a 2 though it looks more like a Z (sorry bout that) where I've marked the pins is where you will place your leads. Set your meter in the 2k ohms setting and take your readings. 

Your meter should read high around 1k ohm or more.


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## murihikukid

hi.. at 200 setting which i presume is 200 ohms...# 1 is dead ..(.ie 1 ) and I took a reading both sides of it.... I also did the same with the DMM set at 2k ohms with the same result..

# 2 is also dead ie 1 ...I tried it on 200ohms and 2k ohms and in the 4 positions that it is possible to do the #2 test ...

So it does look as though we have found part if not all of the problem..Hk


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## octaneman

Seems that way ...That still leaves us with the fuse to deal with. For the time being leave the inverter out of the board. 


What you are going to do is make your own makeshift fuse to supplement the blown surface mount fuse. Unfortunately without a diagram we do not know the ratings of that fuse so we have to improvise. To do this what you are going to do is find the thinnest gage wire you can find preferably from a old VCR or discarded power supply and cut a piece of it.

Strip the wire and separate a *single strand* from it and you are going to solder that single strand on to where the blown fuse is with the rest of the wire. Why ? , because we are going to run an outside power supply to see if nothing else blew. A single strand can handle as high as 4 amps running through it before it goes but it doesn't need that much power running through the board or else it will go up in smoke. 


That fuse is part of the back light circuit on your monitor by putting an external power on the fuse you will feel with your finger what component is getting hot that caused a feed back through the inverter. 



You will need :

12V battery.
Wire (very thin)
Alligator clips.
12 ohm resistor. 
Cold spray. <----- ( its an aerosol that freezes the board to test for overheating, you can find it at your nearest electronics supplier 
FYI Its not cheap )

If you don't have any of these were going to solve it the hard way. 



Do not touch anywhere with your fingers where the inverter was sitting it is high voltage ok ?


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## murihikukid

Strip the wire and separate a single strand from it and you are going to solder that single strand on to where the blown fuse is with the rest of the wire.
I am unsure what you mean by "with the rest of the wire"....I separate a single strand of thin wire and solder it across where the blown fuse is ....is that it or is there more to do with the rest of the wire that the single strand came from...

I will ring up the Electronic shops tomorrow and find out about cold spray..ETC...I presume by alligator clips you mean the wire with an alligator clip at each end and not alligator clips by themselves.. Hk


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## octaneman

HairyKiore said:


> I am unsure what you mean by "with the rest of the wire"....I separate a single strand of thin wire and solder it across where the blown fuse is ....is that it or is there more to do with the rest of the wire that the single strand came from


What I mean by the "rest of the wire" is you are not going to cut off the excess wire after you solder the strand to the fuse. Think of it as a wire holding on to its connection by a thread. 



HairyKiore said:


> I presume by alligator clips you mean the wire with an alligator clip at each end and not alligator clips by themselves.. Hk


Correct, you will use them as jumpers.


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## murihikukid

Hi ..I get it now..Believe it or not I have not even got a 12 volt battery ..I did build a project once with various DC outputs and it must be lying around in a cupboard somewhere ...I see that a 300ml of Freezer Spray is over $30 ...My problem is at my age I probably will not use it more than once ?? I have a lot of resistors etc but they are small ...probably only small wattage ...but probably got a 12 ohm one..I have a lifetime of junk lying around that I am going to get rid of soon...
I have handled the board and so far experienced no kick...I have shorted out the Filter Capacitor with my light bulb each time following any power on test....Hk


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## murihikukid

Hi..Here is my Power Supply..Probably one of my best home projects..Just wonder if it can take the place of a battery or would 12v from a wall tranformer do....I have yet to find a 12ohm resistor ..Hk


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## octaneman

I'm a little envious; beautiful little project you got there, I see it can put out 12V 20mA now all you need is the 12 ohm resistor and you're in business.

btw; If you got a power bar to plug in the board instead of straight in the wall it would be added safety to the board.


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## murihikukid

I am unsure of what is a power bar..I have a Power Guard device that one plugs into ones power supply and one then plugs any tool etc into it for safety..against shorts etc...I must go out side in the light and check my Resistor jar...Hk


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## octaneman

Power Guard or Power Bar, different countries call it different names but it does the same thing. Protect equipment from overload.


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## murihikukid

Ok..Got one or similar..My biggest problem at the moment is finding my jar of resistors??? Amazing how it has suddenly disappeared while similar jars of other components are visible everywhere...I recall opening the resistor jar a couple of days ago..Hk


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## octaneman

If you got a ballast resistor lying around with the 12 ohm rating it'll do just fine.


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## murihikukid

Sorry..I will have to go uptown in the morning ...I found my jar of resistors but found it difficult to read the colours...I know there is no Brown-Red-Black in the jar ....So I will go up to the local Electronic repair shop ...They seem to be far more cordial than the shop that deals in electronic components etc and its not so far to bike??Is there anything else you think I might need while I am there?? Hk


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## octaneman

Aside from aligator clips nothing else comes to mind. But there is something you can do for yourself.
While you are in town ask the shop what suppliers are available that sell inverter transformers and the like, because parts for your monitor may not be available. It will be better for you in the long run it saves you time, energy, and allot of needless running around when you decide its time to order parts.


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## murihikukid

Yes..Its important for me to ask about that ? Hk


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## murihikukid

Hi..I thought my country was built round "do it yourselfers"...Strange the frosty reception I got from the Electronic repair shops about parts for Viewsonic Monitors..However I did get supposedly the NZ agent and I managed to get a 12 ohm resistor ..its a nice large one ...(I thnk he said 1 watt)
I will email the address I was given re parts and check them out....Hk


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## murihikukid

OK..I can see problems ahead ...I have been searching for info here and I do not like what I am finding so just as an off chance I looked on Ebay and found complete power boards for sale ...so now just in case I am trying to activate my Ebay account ..Having changed my email address and forgotten my password that is a near impossability unless I open a new account and just to make matters worse the sellers do not even recognise my country even though we supply them with a lot of food and plenty of racehorses?? Maybe they think we are part of Australia??????????
I have a suspician that even if I found a Transformer inverter here it would cost me more than importing the complete board....Hk


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## murihikukid

I Also contacted one repair service that I was advised to contact re parts...He had never heard of ViewSonic and advised me either give it away or bring it to him to look at???....
By the way I have been looking out for another faulty monitor and I get emailed if any get listed so that is another avenue that maybe worth exploring... 

Hk


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## octaneman

Here's a link for viewsonic in NZ; ViewSonic - Knowledge Base



Call up customer support center and ask about parts and where to get them, if you get the runaround from the operator ask for the supervisor until you get the information you need. 


Word of advice; Call centers are a real PIA to deal with whatever you do don't give up if you have to call the head office division keep hammering at them until you get results.


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## murihikukid

Ok..I have had a reply from the repair agent of Viewsonic and they do sell parts for all Viewsonic products .....Can we carry on best we can and establish if there is more faulty parts ..This would enable me to do a costing of faulty parts as against a complete new power board...??Thanks Hk


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## octaneman

Do you have the resistor and aligator clips ?


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## murihikukid

Sorry Just woken Up.? Yes I have the resistor and alligator clips....Hk


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## octaneman

With the resistor and alligator clips on hand, what we are going to do next is determine if any other surface mount component blew. 

Take the piece of wire strip it and solder a single strand on the surface mount fuse. To make it easier to solder the strand, take your soldering iron station and set it to 210° C and leave it warm up. Why 210°C ? Because SMD's are susceptible to heat damage if the iron is above 235° C and held more than 60 seconds on it. Apply a little flux on to the fuse solder points this will help melt the solder quicker. Separate the strands and leave one thread, cut the excess strands off so they won't make accidental contact with other components. Apply a little solder to your iron tip, align the strand on the fuse and solder it firmly onto the board. Leave an inch or two of wire hanging out of your board so you can connect your power supply without shorting out anything.


The next step is take your home made power supply and set it to 12V D/C, take your alligator clips and clip the negative of the power supply to a good ground on the board. Take the positive lead of the power supply and connect one side of the 12 ohm resistor to it. Turn your power supply on and with the resistor in hand make contact with the fuse wire in a stroking motion for a second or two. 

Observe the board while you are doing this and see if anything will get hot. If there is nothing visually use your free hand and feel the surface mount components for any heat. If there is a short to ground the component will get real hot and it would indicate instantly that the overheating component is bad. 


If the makeshift fuse blows then the problem lies with the inverter drivers. 

Side Note: To locate shorts faster by applying cold spray liberally on a section the board it will freeze components frosty white. When power is turned on from the power supply anything that is shorted will begin to heat up and melt the frost on it instantly indicating which component is shorted.


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## murihikukid

Hi...I hope you do not mind my putting the monitor on hold for a few days...I have the problem of being old and untidy and in a rental property and I have a "property Inspection " on Thursday so I have to devote all my time to cleaning up inside and outside the property just to ensure everything is OK ..Thanks Hk


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## murihikukid

OK..I am back nearly ready to go....I thought I should first attach an image of the soldering station control unit I bought......Hk


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## murihikukid

OK..I have set everything up outside and done the check...I am getting 11.99V from my power supply..The corner of the board where I have the negative lead clipped to is the only real grounded corner and I got a continuity reading from the corner to the first component the circuit track goes to so I am sure I have a good negative connection...
..the single strand of wire across the fuse has not blown ...I can only feel one sensation ..the 12 ohm resistor that I am holding the body of I am sure is heating up ...I have checked the board by touch for any heat from any component and I am sure there is nothing....
I will leave the setup as is for as long as I can incase you want me to do any other check while everything is setup as it is.....Hope the photo is of help ..Hk


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## octaneman

It is a good sign that the strand fuse is still intact it tells us that nothing else for the moment has gone bad. 


What you are going to do next hook up the A/C cord to the wall and do the exact same test, only this time you will hook only your meter to the strand fuse and take readings. 

Set your meter to 25V D/C hook your meter to the strand fuse with aligator clips make sure the negative lead has a good ground. Plug the A/C cord into your power guard this will give you the flexibility to have your hands free to shut off power in case something goes wrong. 

You will take 2 readings: 

The first reading will be on the strand fuse this will tell us how much voltage actually runs through the fuse. 

The second reading will be on the 8 pin connector. If you recall the initial reading was 4.10V, with the inverter removed the voltage should read slightly higher. As it stands there's nothing that is shorting out and from what our previous test has shown the +5V standby should be there. 

Under the board there are inverter drivers I've marked their location on the board. With the power cord on the board touch the mosfets with your fingers are they getting hot ? 



If the strand fuse blows then the inverter drivers are gone. 



The final test will be on the monitor's on/off switch.


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## murihikukid

Hi..I am not absolutely clear on your instructions..Its the hooking up of the DMM ??? Do I Have the Black lead to ground and do I hook the Red positve lead using alligator clips to the wire "extension end" that has the single strand soldered across the fuse...as I have tried to depict per photo attached..Hk


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## octaneman

HairyKiore said:


> Hi..I am not absolutely clear on your instructions..Its the hooking up of the DMM ??? Do I Have the Black lead to ground and do I hook the Red positve lead using alligator clips to the wire "extension end" that has the single strand soldered across the fuse...as I have tried to depict per photo attached..Hk




Yes.


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## murihikukid

Ok..I have it set up so I can switch on via the PowerGuard unit....So I switched the power on and got the first reading reading of 5.03v then switched the power off and it very slowly went down to 0.0 in increments.. 
The 5v pin on the connector is giving a reading of 5.03v also...

The mosfeds are not showing any sign of heat but learning from experience ???Its not the right thing to do to do a finger check for heat on the board ?? I presume I now know what the filter capacitor can hold in it...
Of course the strand fuse is holding and I presume The final test will be on the monitor's on/off switch.....Is it on the Power Board??? cause I am not sure where it is...I hope the above is goodnews and what you were asking for..I have another hour and a half before it starts getting dark so will leave everything set up in case you get back ...As long as it does not rain...Hk


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## octaneman

HairyKiore said:


> Ok..I have it set up so I can switch on via the PowerGuard unit....So I switched the power on and got the first reading reading of 5.03v then switched the power off and it very slowly went down to 0.0 in increments..
> The 5v pin on the connector is giving a reading of 5.03v also...



The mosfets are not overheating which means the drivers are ok. With the test you just did the +5V standby came back, and right now it leaves no doubt than the whole problem with the power board lies with the inverter transformer. 


HairyKiore said:


> Of course the strand fuse is holding and I presume The final test will be on the monitor's on/off switch.....Is it on the Power Board??? cause I am not sure where it is..


The power on/off switch should be where the screen is or embedded within the sub-frame because its not on the power board nor the logic board. 



HairyKiore said:


> I hope the above is good news and what you were asking for


It is more than good news you did an awesome job troubleshooting the board. 
Now that we know where the problem lies, once the inverter transformer is replaced the monitor should fire up. 

Get yourself a frosty case of beer there partner you earned it.

Way to go Hk!!


:beerchug:


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## murihikukid

It is more than good news you did an awesome job troubleshooting the board. 
Hi...You deserve all the credit ..You stuck with me and I will be forever grateful..I am now a Viewsonic VX2235wm-5 expert???? not quite but I have certainly learnt some skills.

I will get availability and cost of the parts ...But it could be beneficial to get the complete new Power Board especially if later another Faulty VX2235wm-5 came on the market and as long as the problem was not the inverter transformer its possible I could fix it by using parts from the faulty power board that I have...
I will let you know what I decide to do and when I have all the parts..

As Regards the on/off power switch..I presume it is on the frame surrounding the monitor screen...There is a series of push switches at the Bottom / front /centre just above the Viewsonic Name and I think one of these is the on /off switch...I have attached a photo of the switch circuit board from the rear ...the ribbon cable goes to the Logic board..

I presume that the power board will need to be fully operable before the on/off switch can be tested...Thanks Hk


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## octaneman

Hk, 


Testing the switches is simple; all you do is disconnect the molex plug on the board then set your meter on continuity. Place your leads on to the pins with respect to the switch's wire color code ( red wire is positive lead black wire is negative lead.) and press the switch, your meter should give out a tone indicating the switch is turned on.


----------



## murihikukid

Thanks..What I have circled I am sure is what you refer to as the molex plug..Could you please confirm this ..Hk


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## octaneman

I've circled the molex plugs in yellow; Remember you should hear a tone only when you press the switch on , when you release the switch no tone.


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## murihikukid

OK..Still waiting for parts price ??

Re Soldering Stations..I am wondering what these will end up going for....

Hakko 950 SMD rework tweezers | Trade Me

Hakko 928 soldering station | Trade Me

Cheers Hk


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## murihikukid

WHATS Happening ??? Its not Xmas>>
The Viewsonic Agency has just replied to my request for a price on a F101 Fuse and Transformer Inverter by asking for my address so as they can forward a complete Power Board free of charge......They do not say if its brand new but even if it is not its a great offer...Hk


----------



## octaneman

HairyKiore said:


> WHATS Happening ??? Its not Xmas>>
> The Viewsonic Agency has just replied to my request for a price on a F101 Fuse and Transformer Inverter by asking for my address so as they can forward a complete Power Board free of charge......They do not say if its brand new but even if it is not its a great offer...Hk




Thats great news you'll be up and running in no time.


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## murihikukid

octaneman said:


> Hk,
> 
> 
> Testing the switches is simple; all you do is disconnect the molex plug on the board then set your meter on continuity. Place your leads on to the pins with respect to the switch's wire color code ( red wire is positive lead black wire is negative lead.) and press the switch, your meter should give out a tone indicating the switch is turned on.


Hi ..I presume there is a technique involved here ...I just cannot figure out how to hold the DMM leads on and press what I think/presume is the on/off switch ...Unless I carefully solder temporary wire's to the molex socket pins....which would enable me to connect to the DMM leads using alligator wires...Then I can press the switch...
Also there is a molex plug on each end of the circuit board ...do both have to be tested... Thanks Hk
PS..Actually after another look I think trying to solder wires on is too dangerous and a better idea would be to try and buy another Molex plug/socket the same and put a wires on the plug and use it to plug into the socket...


----------



## murihikukid

Hi..I have attached a photo of one of the molex plugs.....now the red and black wires go into a small casing and I do not know what is in the casing ...whether it splits apart when the two screws are removed ....
I am wondering if the red/black wires with the molex plug on its end can be easily and safely removed from within the casing ...and put back in place when I have done the test..Thanks Hk


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## octaneman

The box should come apart when you remove the screws, from what I see in the picture there is a notch on the top left corner so my guess is the screws also act as mounting bolts. The red and black wires are most likely soldered on to a small board within the box so it shouldn't present an issue, if you place the leads where the wires are soldered you can still do the test. 


If you see that the box doesn't come apart don't bother doing the test.


----------



## murihikukid

Hi...I wondered if they did have something to do with sound and they are small speaker box's (left and right) but completely sealed although I presume the small speaker is prewired and then pushed in and possibly does come out revealing the two wires..but I am not prepared to risk it .The box itself has a small rubber grommet in each corner...I will go up to the electronic shop and seek out a molex plug by sight ...or there surely will be something they have that one can push onto the two pins and can be prewired..
My more elderly neighbour is infatuated with a helicopter from this shop and has asked me to let him know if I go up there ?? Now that could be dangerous with one of those flying around..Hk


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## murihikukid

OK...In the end I took it across to a neighbour to operate the power switch while i operated the DMM...and I do not know what these tests represent ..I wonder if the power switch when pressed and released..Is it on and has to be pressed and released again to switch it off???
So the front screen was upside down with the power switch/circuit board closest to me ..This will enable you to understand left and right...
Now I have suddenly realised that when I tested the left molex it of course was unplugged BUT the right plug was not unplugged so maybe I have made a mistake....???????

Anyway the left molex socket gave me nothing as far as a continuity test when my neighbour pressed the power on/off.....Just as an after thought I decided to test the right molex so I unplugged it which meant both molex's were unplugged...
The right molex gave me a continuity sound .a continuous sound...even though I kept asked my neighbour to keep pushing it and releasing....
What terrible switches they are...to operate..Hope this helps Hk


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## octaneman

Hk, 

It doesn't matter if the molex connectors are plugged or unplugged to test the switches, you can test the switches either through the molex pins or from the red & black wires. The point being is that with the switch pressed your meter should give out a continuity tone and when its released it shouldn't. The monitor's power on/off switch no matter where its location if its soldered on to any PCB ( printed circuit board) no matter how its orientation is its marked on the board as ON/OFF like any other component. 

I can't tell from the picture those molex connectors are connected to any switches, but from my perspective looking at it as is those black boxes are speaker housings and the wires are its connectors. Your meter set on the lowest resistance scale you should read a speaker resistance of approx 8 ohms. 


Can you take a picture of where the on/off switch's location is ? I need to know where it is and how its mounted. Please take pictures on the front of the monitor and the back.


----------



## murihikukid

Ok..Its in the middle of the night and the hail woke me up and its cold so winter has arrived..:dance:..I have taken a photo as requested but its not good ...The monitor is lying down on a towel face up ..I have circled the on/off switch which sits below the screen in the middle and above the Viewsonic sign....It has in its middle a clear segment which I believe lights up and one can clearly see this in the photo ..on either side of the power switch are two other switches (so 5 in total )..they are used for adjusting the monitor...DIRECTLY behind the 5 switches(if I turned the screen over ) is the PCB board (as in my previous photo) so I presume these switches are all mounted on the PCB board...There is no visible markings on the PCB board outer so perhaps there is on the underside....Do you want me to try and figure out how it comes off....???
My tests .in my opinion do not make good news ....I presume my neighbour was pushing the on/off switch as per my directions and to get no continuity on the left and a continual continuity on the right does not sound right....I had the multimeter leads touching the 2 pins within the molex socket....as I had disconnected them from their relative speaker housing..

Now I did remove one of the speaker housings to see if there was any place to take a reading there but they are sealed housings ..The small speaker is no doubt pushed into the housing having been prewired with 2 wires coming out from within the housing...I have tryed to find out on the internet how these speakers come out but found nothing...cause I was searching for an easy way to get a DMM reading..

I hope this answers your questions ...Hk


----------



## octaneman

Yes, look on the underside of the PCB see if there are any markings. I see markings in small print where the molex connectors are can you make out what it says ? If those are speaker connectors then were looking in the wrong place.


Your continuity test don't make sense to me unless the power switch has multiple pins. If the power on/off switch has multiple pins it would explain your readings because the indicator light runs off an LED. The LED indicator light tests exactly like a diode continuity on one side but not the other. It also uses multiple colors which varies with voltages. For example; Orange light means its on +5v standby, Blue light at full power +13v to indicate to the user at what state the screen is on so the switch under test could in fact read continuity at all times. You have to positively identify the power on/off switch on the PCB to verify your readings.


----------



## murihikukid

Yes..They are speaker connectors...however the hail has gone ,the sun is out and I have been able to take it outside and take photos so hopefully they will reveal all...I actually never saw any print where the molex connectors are..
I am sure the tests you require can be done from the underside of the PCB..If I had only known how easy it was to just lift out the PCB?? However I presume the bike exercise would have done me no harm...Thanks Hk


----------



## murihikukid

Oh Dear..as the sun was shining I left the monitor outside while I came inside and processed the photos and got my posting away...I have just gone outside and had to rescue the monitor from very fine spits of rain that are on it....I presume I just let these dry naturally in the bathroom which is reasonably warm as it has a heatlamp as a light...Hk


----------



## octaneman

Ok, 

The switch has 4 pins I've marked the pins as A, B, C, D in yellow. To test the switches set your meter on continuity. 
The pin connections are interchangeable so it doesn't matter which pin pairs you select to put your black or red lead. 


First test: 
Place your leads on pins A and B your meter should read continuity.

Place your leads on C and D and your meter should read continuity. 


Second test: 

Place your leads on pins A ,C your meter should read infinty (1 on your meter) when you press the switch the meter will read continuity.

Third test: 

Place your leads on B, D your meter will read infinty (1 on your meter) when you press the switch your meter will read continuity. 



Now you will have to bear in mind that we don't have a diagram and viewsonic may not have the micro switches aligned the way I have set up the test. But the thing to remember on 4 pin micro-switches that one pin pair reads continuity and the second pin pair reads continuity *only* when the switch is pressed.


----------



## murihikukid

Hi..Both A-B and C-D read continuity....I have pushed the small button to see if there is a difference IE no audio but I get an audio all the time...I now wonder if I should do a test from A - C , A - D, B - C and B - D....Which I think covers all the variables.. 
OK...I have done the variables best I can so hope this makes sense....
A - C ...B - D.....A - D.....and B -C....All give a continuity reading ONLY when the switch is pushed..
Hk


----------



## octaneman

It makes perfect sense the switch passes the test. 

Good job !


----------



## murihikukid

OK Thanks.. No Power Board yet..It may arrive tomorrow Saturday..if not hopefully Monday...Hk


----------



## octaneman

Hk, 

When your power board arrives and you're ready to assemble everything back together, the most important connections are the ribbons. The ribbons must be perfectly *straight in * and secure with their respective socket pins or else the variable voltages that pass through the ribbon doesn't go to where they're supposed to causing major headaches when the monitor is fired up. It is good practice to always double check the ribbon connections before you close it up.


----------



## murihikukid

OK Thanks..But so far I have not had to disconnect a ribbon connection or what I recognise as a ribbon connection..Hk


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## murihikukid

Hi...I have now got the power board ..Later today I will be plugging it into the unit....Now at this point I wonder if I should test the unit at this point before I put all the covers etc back on ...Your comment on this would be appreciated...Hk


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## octaneman

Before you do anything inspect the board visually for any sign of component burn out or physical damage. It is best you test your board before closing it up it would save you the hassle of tearing it apart again. Please be very careful when you connect the boards together that all pins and ribbons are in their proper place before you plug it to the wall.


----------



## murihikukid

Hi...I finally got out of bed...I have just unwrapped the new PB and its identical to the old one except two components (circled )are on the top of the board while on the old board they are located on the circuit side...Will have some breakfast and then get it installed...Hk


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## murihikukid

Hi..Well I powered on via my Power Guard and no sign of any life so I quickly switched off ... It may well be that with the unit lying down as it is ..my switching the on / off switch on the monitor was not successful.....I will just wait for your comment here ..there maybe a test I can do?? with the DMM...Thanks ..Hk


----------



## murihikukid

Hi..Just thinking back I presume a test for 5V at the appropriate connecting pin would tell me if there is actually power in the unit...Hk


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## murihikukid

Hi..Sorry there is a Blue Light showing on the Power On/Off switch ..I will have to look up the manual to see what this signifies ....and whether at this point the back lights should be on... Hk


----------



## octaneman

The back light was turned on with old power board the problem you are facing now is the inverter not switching. The circled components are the inverter drivers which are just oriented differently from the original board. 

The board is slightly different from the original, whats important is making sure all the feed voltages that are needed to power up the board are there. The original power board had no sign at all that the +5V standby was present but the back light was turned on, the new board is giving the opposite symptoms that there may be something wrong with the inverter drivers.


You will need to take down the numbers on the inverter drivers because we will have to test them and the inverter transformer, then verify that all the voltages are on the pins and that the main transformer is switching.


Question: 

What did you mean when you said: " It may well be that with the unit lying down as it is ..my switching the on / off switch on the monitor was not successful... " 

Where you not able to press the on/off switch ?


----------



## murihikukid

Hi ..At the moment my biggest problem is that my Eye magnifying glass has disappeared...Strange as all my work equipment is in a bowl ..I just cannot understand it..It was so crucial to me...
Anyway I have now got the markings on the inverter drivers..both are the same..
40T03GP
6
746520

.Yes I lifted the unit up on an angle and could see no light on the power switch so I pushed it and looked again but still no light or so I thought ...When I went back later and had another go the blue light was clear....In my excitement of anticipation I may not have even had the Power Guard on in my initial try....Hk


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## octaneman

Do you see the back light on ?

If not what is it you wish to do troubleshoot the new board ? Or just remove the inverter transformer and tranfer it to the old board ?


----------



## murihikukid

Hi..No there is no back light on and I am confused about what is exactly happening here....Now as I understand via the manual the blue on the power switch means the power is on...As I understand I press the power switch and the monitor should switch off IE the Blue light goes off....WELL the blue light stays on no matter how many times I press the switch ..It certainly goes out when I cut power via the Power Guard ,but it seems to me there is a problem at the power switch ..As for the power board ..either way is OK with me ....I know just transferring the inverter transformer would be the easiest but I am trying to learn here as best I can and trouble shooting the new board will do this.. thanks Hk.


----------



## murihikukid

Ok..I made a mistake as I should have forwarded the full power board particulars when I made my original enquiry...The new board sent to me is a DAC-19M005 AF Rev-02A....My board is a DAC-19M010 AF Rev-00A.....Of course I have no idea what difference there is....I wonder if I should email the company manager who sent the board and ask him as he should know...Looking at Power Boards for sale on Ebay it seems that some boards have no audio..Hk


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## octaneman

The boards are not the same the difference lies in the make up of the board which of course you found out about it already. The power board must be the exact original number because certain irregularities between the two make up all the difference.


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## murihikukid

OK...I take from your reply that the board sent to me is not compatible so I am basicly back to square one...I have been trying to cover all bases by continually monitoring any other VX2235wm that are put up for sale...
I am presuming here that the Inverter Transformer on both boards are the same?
I will email the company that supplied the board and explain my position and I will explore the possibility of getting a board from Ebay USA... Hk


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## murihikukid

Delta Power Board For DAC-19M010 AF Viewsonic VX2235WM | eBay
Hi..I am registered at both Ebay and Paypal ...I see this power board which is as far as I can tell identical to my board...It also offers (I think??) Free International shipping ....Do you think I should just buy the right board and get it sent over to me...
thanks Hk.


----------



## murihikukid

Power Supply Unit DAC-19M010 AF DAC-19M005 AF 4 lamps inverter NEW | eBay
Hi..I see this power board is being listed as a DAC-19M005 AF ....and a DAC-19M010 AF Rev-00A. Hk.
PS..I have now found a Brand New one for the equivilant of a used one...AND there is no doubt I will recover my cost on this item if at the end of the day we do not use it..


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## octaneman

As long as the pin outs of the inverter transformer are the same it should fit your old board, but it all depends on what you want to do. If you plan on giving back the new board and get a refund then by all means do so, that would be your best option in order to minimize the cost of repair. Buying a brand new board instead of second hand would be best because the monitor's repair would be permanent and will last a few more years with a warranty.

Remember, when getting a new board the serial numbers have to be exactly the same, don't assume that just by looking at components that are placed in the same orientation mean that they are identical. 


Note; This board here is not the same as your original ------> Delta Power Board For DAC-19M010 AF Viewsonic VX2235WM | eBay, . 

keep us informed of your progress.


----------



## murihikukid

Hi..I cannot ask for a refund cause it never cost me anything and thats why I am hesitant in asking questions ..It might be best for me to just accept the freebe and leave it at that ..I was not even charged courier service.......It does seem strange that they would send me an incorrect board but thats apparantly is what has happened..

Yes the link Delta Power Board For DAC-19M010 AF Viewsonic VX2235WM | eBay...I posted ...The auction states AF while the photo says its BF.. (I wonder what the difference between AF and BF is )

Here is the link to the new board I am looking at...Unfortunately the photo is really poor but I can make out 
DAC-19M010 AF
2995306200
REV: 00A
New Delta Power DAC-19M010 AF For Viewsonic Acer | eBay

Those numbers equal my board but there are other unreadable numbers so are the boards the same ??? Hopefully you will be able to tell me if they are...I presume I could ask for a photo of the Sticker on the board and the numbers just under the sticker...If you give me the OK I will just buy it as it could take 3-4 weeks to arrive ...
In the meantime i presume I could try putting the inverter transformer from the board just received and putting it in the original.....and trying that..?
Thanks Hk


----------



## octaneman

HairyKiore said:


> If you give me the OK I will just buy it as it could take 3-4 weeks to arrive ...


Go for it !!

The only other numbers I see are on the transformer and the numbers are a perfect match with your old board's transformer. 

You should get in contact with the seller and find out approx how many working hours the board has on the clock. For example: If the power board is 6 months old its equivalent to 5000 hours. Its not that critical but have it in the back of your mind just in case something gives out. 

In the mean time; you want to give it a go with the other board's inverter ? 
You never know it may work out.


----------



## murihikukid

Hi..unlike other boards from the seller this board is listed as new ...(2 months warranty) Its about $3 more expensive than the used ones but that seems a small price to pay .....I will buy it now and hopefully it all goes without any problems ..Well its all paid for ..so I just have to wait for it to arrive and hopefully I am sent the board that is actually listed...In the meantime I will change over the Inverter Transformer and I presume the Fuse also ..Hk


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## octaneman

Will you work on the old board ?


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## murihikukid

octaneman said:


> Will you work on the old board ?


Yes ..That is what my intentions are... Hk


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## murihikukid

Ok..My NEW turbo soldering bolt only lasted less than an hour usage..Its a good job I used it tonight instead of my soldering station as I can take it back under the 2 month guarantee...and get my money back ? I unsoldered one joint and could not understand why I could not get the next one unsoldered til I realised the bolt had stopped working..
SO
I have removed the Transformer inverter from the new board...and tested it..and have posted the results on a photo....I went back to page 9 and looked at the results from the original board and they look very similar???? I am sure I have done them right with the DMM set on continuity.

Plus I presume the F101 fuse can be easily removed as I believe its called a surface mounted fuse...and I can use it to replace the fuse on the original board which is blown... Thanks Hk


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## octaneman

Something isn't right with the inverter readings, the primary side has to be a LOW resistance reading between 0-2 ohms and the secondary has to be HIGH resistance reading in the vicinity of 2k ohms. Re-do the test again the inverter on the new board and the old board can't have the same readings. Keep in mind the inverter has to be completely off the board to be tested.

If you can post a video of how you test it we can figure it out. 


Don't replace the fuse until you know the screen will fire up with the new inverter installed. You will be using the strand fuse as the guinea pig, so in case it goes its the strand the burns out not the new fuse.


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## murihikukid

Hi ..The inverter is completely off the board...I will redo the tests soon...In the meantime things could not be worse ...I used Buy it Now on the Ebay listing for the New Power Board ..I paid for it via my Bank Debit Card and Paypal and NOW today the seller informs me via <[email protected]> that the item is out of stock and they will refund the money...I do not understand how Ebay/Paypal and the seller can allow this to happen ..

The one strand wire fuse has broken off my board so I will have to redo it...
NOW RE THE TEST....
As you can see I have used continuity on my DMM to test the FOUR centre pins ...Do I use an ohm setting on my DMM for the two sets of outer pins ...Cause the reading I have given was done with the DMM on the Continuity setting...Thanks Hk


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## murihikukid

Hi..Done another test on the "New" inverter from the New Power board..I have used your original photo attached to depict what I get....On the 2 pairs of centre Primary pins I get continuity across each pair...and with DMM on 200ohms I get 00.2.....Across the same pins..as depicted in white on the photo

THATS IT.????...There is no other continuity between any other pins or on 200 ohms I get 1. and I am sure this is not what you are looking for?

Looking at the windings ..I certainly do not like the look of the secondary windings ..it looks like a frost outside which means it could be a nice day in 12 hours time and I could take a photo to try and capture the signs I am referring to..
If I know this inverter is completely dead I will email the company that sent it and tell them.....they may offer me something else ...surely by powering the board I could not have done damage....of course having removed the inverter there are obvious signs I have done this..
Also 
I have emailed the people offering THIS power board on ebay ..it is available but I am not convinced that its the same board..it is a BF not an AF
New Delta Power DAC-19M010 BF for Viewsonic VX2235WM | eBay
And
there is differences in numbers on this boards components EG Transformer 
DELTA
2874006000
E115982 MP-1301
DCGM 0816B

as against
DELTA
2874006000
E115982 MP-1301
DCGM 0736B

I wonder if the computer code sticker on the board with 
M$27-D015885-L$DGTR739300233-00A
on it ..tell one its an identical board...

I have done extensive searches on Google re power boards for sale and they all lead back to Ebay ....Naturally I really do not want to use Ebay/Paypal again til I hear back from them re the listing I purchased ,paid for and then denied under the excuse "out of Stock"...
Thanks Hk


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## octaneman

The meter readings on the primary appear to be OK its on the secondary windings the readings you get is whats giving the problem. 

The inverters primary side are the first and second readings which as you can see I've placed arrows to show where your leads are placed. The meter readings you got was 0.2 ohms on the 200 ohm scale. The readings are consistent of what it should be on the primary side a LOW reading. 


Third, fourth, fifth, sixth readings are the secondary windings which the arrows pointing is where your leads should be placed. This would give readings on the kilo ohm scale because it should be a HIGH reading this is where the problem lies. 

When you take your readings your meter settings should be one setting above the 2k ohm scale because the resistance within the secondary is higher than the primary. The meter says 1 ( infinity) when you got your initial readings. This is wrong because if the secondary is 2.5k ohms from factory your meter won't pick it up because the meter's scale is set to low. 


Don't forget that viewsonic could have re-arranged the pins *diagonally* on the secondary side this is what we have to figure out.


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## murihikukid

OK..How is This...
First readings = Nothing
Secondary Readings = 00.3 @ 200ohm setting
Third reading = Nothing
Fourth Reading = 0.73 end/outer reading @ 20k reading
Fifth Reading = Nothing
Sixth Reading = 0.74 @ 20k setting
Hk


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## octaneman

At the third & fifth readings if you set your meter on the 20k scale do you still get nothing ?


Can you post the serial number thats on the inverter transformer ?


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## murihikukid

octaneman said:


> At the third & fifth readings if you set your meter on the 20k scale do you still get nothing ?
> 
> 
> Can you post the serial number thats on the inverter transformer ?


Hi..Re Third and Fifth Readings I have tried 200ohm ,2k ohm ,20k ohm and 200k ohm...the DMM does not move from 1. on any..

Inverter Transformer Serial Number =
2874005300 M F. 0750 
(the final number is difficult to see but I am 95% sure its 0 ) Thanks Hk


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## murihikukid

Hi..I thought it might help if I posted a photo of each inverter ..Of course I know nothing Re windings etc but it seems to me that there is a crossover on the secondary windings on the original inverter which is not evident on the inverter from the new power board.. you will also see (although not clearly) on the right hand side of the new inverter, what I pointed out in an earlier post about the windings looking not quite right?? 
In fact I have managed to take two close ups and have posted them also...
Also here is the Serial # on the Original Inverter in case you want it.
2874006101 M F 07371
..Hk


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## octaneman

Hk, 

You're right; the new inverter is not the way it should be, from my observation I see the windings to be burned out and the reason for secondaries poor resistance readings. 


The original inverter looks in decent shape and has no visible signs of damage which is troublesome. We are going to re-examine the old inverter's secondary side once more just in case we missed something the first time around OK ? 





Please post back the results on the old inverter.


----------



## murihikukid

OK..I have attached a photo with the test results I have just done..NO other pins give a reading...hk


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## octaneman

The results are fluctuating on your first readings on post 9 you had .456, now the indications are that the inverter's secondary windings are 0.52 kilo ohms. This is equivalent to 520 ohms which is still a low reading. The primary is OK. 

This leaves us with a contradiction, either the drivers are not working or the secondary of the inverter has shorted.

Right now its not leaving us much of a choice, were going to need the numbers off the mosfets to test the drivers from the original board its the only way to narrow the field. 


Side Note: I'm making some inquiries on your inverter by getting its specs.


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## murihikukid

Hi Sorry You have lost me....This leaves us with a contradiction, either the drivers are not working or the secondary of the inverter has shorted.

Right now its not leaving us much of a choice, were going to need the numbers off the mosfets to test the drivers from the original board its the only way to narrow the field. 

I cannot even recall what the mosfets are ..I went back through all the posts and just got lost ..When you say numbers is that the numbers on the mosfet or a reading ..Hk


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## octaneman

The mosfets are the IC's that are underneath the board that drive the inverter ( page 10, post 193) we'll need the numbers from the IC's to locate the datasheet.


----------



## murihikukid

Hi..Gee these are so difficult to read ...There is no sun outside which would make it easier I think ....I am using a headband magnifyer plus a hand held magnifyer...and this is what I have come up with...Please get back to me if you think its wrong..
They are both the same...
997 3GH or 997 36H
4 (in a circle)
731346

Hk...


----------



## murihikukid

Hi..Its 9973GH ..Hk


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## murihikukid

Hi..Got your message plus been advised another board is being sent ???Hopefully with a good inverter?..Hk


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## octaneman

Testing MOSFET drivers.



There are two types of MOSFETS N channel and P channel. The difference between the two is the P channel type is switched on with negative voltage. Yours is the N channel type.

To test Mosfets they have to be switched on. What I mean by this is once off the bench, your meter should provide enough voltage ( around 3.3 VDC) to switch it on. Depending on the mosfets specs, some may require an outside source to do this but we'll worry about that later. 


To test them they have to be desoldered off the board. Mosfets are susceptible to static electricity, one jolt of static electricity and they're fried so you have to be really careful with them. 

The package type of your mosfets are smd's which requires extra care when you are taking them off the board. 

Set your soldering station to 220 degrees and apply the heat no more than 60 seconds at a time or else you burn out the mosfet. Use only the braid to remove the solder not the solder sucker, because it can generate static electricity. 

Once you have it on the bench, take your meter and set it to the 200 ohm scale. Place your positive lead to drain and negative lead to source and measure the resistance. Your readings should be from 100 to 10,000 ohms in both directions. If not mosfet needs to be replaced.


Next reading; meter on 200 ohm scale. Connect the positive lead to the gate. Take your negative lead and measure the resistance between gate and drain and then again between gate and source. Both your readings should show low resistance and approx the same. If not mosfet needs to be replaced.


Next reading; meter on 200 ohm scale. Disconnect the positive lead from the gate and connect the negative lead to the gate. Using the positive lead, measure the resistance between the gate and the drain; then measure it between the gate and the source. Both readings should indicate infinite resistance (1 on your meter) 
If not mosfet needs to be replaced.


The data sheet will show you where Drain, Gate, Source is on the smd's to place your leads, test both mosfet drivers the same way. 


post back your results.


----------



## murihikukid

OK...Got a couple of photos taken earler when it was beautifully fine outside....Hk


----------



## octaneman

Hk, 

Here are the pin outs as I see them.


----------



## murihikukid

Hi..I have my first problem ...Clearly my soldering station set at 220 (which I presume is the degree reading ) ...is not going to melt the solder .... I have only tried so far on the solder at the end of the mosfet which I presume is holding it to the board....Hk


----------



## murihikukid

Hi..Just in case it helps I have posted a photo with the linking wires in yellow that are on the top of the board..Hk


----------



## octaneman

Don't touch the jumpers they are not in the way. 

Apply solder flux to the mosfet joints before you place the iron or else you will have difficulty, increase the temperature if you have to but not above 230 degrees then apply the braid.


----------



## murihikukid

Hi..NO.. i never intended touching the jumpers..I have not purchased any solder flux yet cause its so expensive ...Its ridiculous?? What I have been doing is melting a small bit of Solder with flux onto a joint which has worked BUT I will see again if I can get a small amount of flux from somewhere..Hk


----------



## octaneman

If you got some plumbing flux lying around it'll work.


----------



## murihikukid

Hi..I will ask my neighbours if they have anything ...I used to have these things many years ago??? Even at 230 there is nothing ....I found taking the inverter out I had to use my very fine handyman flux solder and merge a small bit of it on the original solder joint and then grab my Solder sucker and use it as quick as I could..I have googled for some solder info and I see that there is probably a skin on the solder and it needs flux....Unfortunately its a Public Holiday Tomorrow (Queens Birthday holiday but its not her birthday ??? ) so Tuesday I will try a plumber or two and see if I can buy a small amount .... Hk


----------



## octaneman

Hk, 

Did a little research on your solder station, its maximum settings is at 430 ºC or 806 ºF.

Are you sure you have the right temperature settings ?

The smd's shouldn't be giving you a problem. Is your soldering station temperatures set in the Celsius or Fahrenheit scale ? 
230 °C is 446 ºF more than enough to melt solder.


----------



## murihikukid

Hi..I found this on the JingLing JLT-01 Professional Soldering Station with digital Display. Temperature-indication in the display. Heating Power: 48W Temperature range: 150° - 480° C Iron voltage: 24V Soldering iron length: 198mm Dimensions: 170 x 116 x 96mm 

On the LCD screen I can see a C and this can be seen in the photo..but it does not light up so I presume its Celcius...But am I setting this right..Well to be honest I now really do not know..On the picture posted I have circled a switch ...This switch I think when clicked to the right allows one to set the temperature required (a Stable setting) ...If I click it to the left I get (up and down) incremental readings which I presume are the actual temperatures of the bolt itself as it heats and cools ...
I wonder if I should carefully scrape the surface of the mosfet solder and remove any surface impurities to see if that makes a difference...I will try and get some flux later from a neighbour if he is home and not at his holiday batch..Thanks Hk


----------



## murihikukid

Hi...I bought 100ml of soldering flux ..I have cleaned the bolt etc and even scraped the solder on the mosfet with the point of a sharp knife before applying flux then tried with a setting of 220 then 230 ...it will not touch the solder on the mosfet.....So to me its quite evident that the bolt does not have the heat required ....I am basicly left with one option and that is to lift the setting up by 10 til the bolt actually works on the solder.. of course the problem is I do not know if the soldering station is actually displaying a correct setting...Please advise if you have an alternative ..Thanks Hk


----------



## murihikukid

I am up to a 280-290 setting and it does not look like liquidfying ..Hk


----------



## octaneman

Use maximum temperature on the dial but don't keep the bolt on too long .


----------



## murihikukid

Hi..I can actually see me ruining the whole board doing this...I Just cannot lift or break the solder joint on either side of the mosfet ...I have only two hands ? I cannot get anything under the mosfet to apply upward pressure and lift one side ...If I could ...it would be easy....I have tried a pair of surgical pliers actually holding the mosfet and trying to Lift it ....I cannot break the solder joint on either of the two pins let alone the plate that solders the mosfet to the board ..opposite the pins ..

The only way I can see is get a tool with a sharp point that one can get under a pin so as one can lift it while the bolt is applied ...then do the other pin..so as the two pins are completely free..BUT will these pins bend ?? If they do not it will destroy the Mosfet ..If I can get one side lifted it then becomes straight forward ..Oh Yes I have tried the braid several times to draw up the solder but I still cannot get it all to enable the joint to break....Hk


----------



## murihikukid

Sorry ..I applied pressure under a pin and it snapped off with part of the Mosfet casing so thats that...All I can do now is wait and see if/when the replacement board arrives and try it...Hk


----------



## murihikukid

Hi..Just as a suggestion ...If you think that there is a chance that the original Transformer Inverter is alright...would it be worth trying it in the board that the blown Inverter came from...The Mosfets on it do have a different number ( 40T03GP ) By the way I did consider cutting the pins on the Mosfets above the solder joint and these could have been soldered together once tests were done ...On Reflection I think this would have been the safest way ....Hk


----------



## octaneman

HairyKiore said:


> Hi..Just as a suggestion ...If you think that there is a chance that the original Transformer Inverter is alright...would it be worth trying it in the board that the blown Inverter came from...The Mosfets on it do have a different number ( 40T03GP ) By the way I did consider cutting the pins on the Mosfets above the solder joint and these could have been soldered together once tests were done ...On Reflection I think this would have been the safest way ....Hk


To answer your question; Yes, there is a good chance of the original inverter working on the new board I would definitely give it a go. 


It's too bad that it didn't go well with the mosfet take this a learning experience, when dealing with any component you NEVER force anything off a PCB EVER. The melting point of solder is 180 to 190 °C ( 360-370 °F) its a little disheartening that an smd gave you that much trouble, but its no use looking back whats done is done (I've done worse OK ? don't worry about it). Don't look at this as a failure, use this opportunity to practice your desoldering technique on the damaged mosfet please don't give up on it. Work on it until the darn thing comes off, you're going to need the experience from it to handle other jobs when the new board comes in. 

Never use x-acto knives, scrapers, picks, pins or any form of TNT to dislodge solder joints. The only thing you will be using is the IRON ..period. It will be difficult at times, but it will become easier once you refine your technique.


----------



## murihikukid

OK..It seems to me that one has to completely desolder one side of the Mosfet so that its completely free..Either the pin side or the mount side ....In my opinion the mount side was impossible which left the two pins ... I spent a fair bit of time trying to soak up the solder round the pins with the braid (that I have ) and clearly I was getting nowhere ... so this leads to my question re the solder sucker and static electricity..is there static electricity in the solder sucker itself ?? or like in computer repair can one guard against static electricity cause its clear to me that had I been able to use the solder sucker I may have got the pins desoldered....
Now re a replacement Mosfet...I could ring up the local electronic part shop but I know what they will say ..Look up our (they are a Franchaise) online catalog ??? Which I have already downloaded ages ago and already looked at what Mosfets are listed in it...and there is no 9973GH...but just to make sure I have just rung them and yes I was right (refer to catalog).... So I rang another repair shop who has always been pleasant to deal with and they are going to look around for me...
In the meantime I would welcome any further comment on using the solder sucker..Thanks Hk


----------



## octaneman

Static electricity can come from your body or equipment, to prevent it techs use the grounding method by use of a wire bracelet. You can guard against static electricity by grounding yourself or use a 1Mega ohm resistor between you and your gear , static electricity voltages can range from from 10 to 30 KV. ( 10,000-30,000 volts)


----------



## murihikukid

Ok..I have got a computer Repairmans Static bracelet....Plus I have thought of another way that may work?? and I am wondering why I never thought of it previously ..I have a set of automotive feeler guages ..What would happen if I liquified the solder and just pushed the finest feeler guage across under the pin to break the pin solder and stop it getting a hold on the circuit board..The finest of those guages is really thin and I could do that procedure with two hands ..Once the two pins have zero contact I can just liquidfy the solder on the mount on the other end and simply lift the mosfet off with my fingers..
I wonder What you think of that idea..
I do have one pin left on the broken Mosfet to try it on as long as you do not see any dangers to the board doing such a procedure..
Hk


----------



## octaneman

Your idea is sound but the only danger is when you lift the mosfet from the board, be careful not to destroy the copper trace because if you do you will damage the board permanently.


----------



## murihikukid

Thanks Will be very careful that the solder is liquified before I try to guide the feeler guage under the foot of the pin ..As long as I can actually get it under the foot of the pin I think it will work...
I do not know how long it will take for the next board to arrive and how long it will take the parts shop to find out if they can get a new mosfet..Hk


----------



## octaneman

If you are an online shopper you can get your mosfets and all your electronic components at these links which are available through their NZ distributors ; 

DigiKey Corp. | Electronic Components Distributor | New Zealand Home Page

Mouser Electronics - Electronic Component Distributor


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## murihikukid

Hi..Unfortunately I get "no Result" from either link when I do a search for 9973GH...same as my local company who rang me and told me they had no luck using that number...I also asked him about my feeler guage idea ..I got the impression he had heard of something similar and said it should work and I will take care of the copper tracks...Now back to the mosfet ..I wonder if there is an alternative number?? I do see the board sent to me with the burn't Transformer Inverter has different mosfets...but their number does not show up in results either..Hk


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## murihikukid

OK..I finally found something ...Electronic Components - Hong Kong Inventory Limited ..
I found other electronic web sites but a 9973GH search realised nothing but as you can see this HK link brings up many suppliers in China ... 
I presume this is what I need ....Hk


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## murihikukid

I really need to find a home supplier ...I am sure 1 unit would interest nobody especially in China..
I am probably floundering in the water here but I wonder if one can cross check a component against a manufacturer ..The 9973GH is apparantly AP9973GH and the AP stands for APEX which I presume is the manufacturer....Now on the mouser Link I found this on N Channel Mosfets
N-Channel MOSFETs

This made me wonder if a clone of a AP9973GH is made by another manufacturer with the same characteristics but under a different part and manufacturers name.....and one can check this via the listed characteristics..
Thanks Hk


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## murihikukid

octaneman said:


> Static electricity can come from your body or equipment, to prevent it techs use the grounding method by use of a wire bracelet. You can guard against static electricity by grounding yourself or use a 1Mega ohm resistor between you and your gear , static electricity voltages can range from from 10 to 30 KV. ( 10,000-30,000 volts)


OK..What I would like to do is try my solder sucker and see how it works on the mosfet pins ....can I put a normal anti static computer unit round my wrist with the alligator clip end to a negative on the board and use the solder sucker safely ...Thanks Hk


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## murihikukid

Sorry about all these postings...I have just found this Page...
http://www.diodes.com/_files/news/0_lnk_090721000504.pdf

Under Cross Reference ..I have found the AP9973GH....and I wondered if the listings to the left and right are the same Mosfet ..made by different manufacturers ..
If they are surely that would increase my chances here of purchasing them ...Presuming one would buy a pair ....Thanks Hk.


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## octaneman

Hk, 

The only information about the mosfet is from Standard Silicon its the only company that carries it you can contact them through the asian distributors; 

SSC: Contact


----------



## murihikukid

Hi..The two links you gave me on your second last post ....I can do a search for both and get results on these...
DMN6068LK3
AOD444
FQD20N06
ZXMN6A25KTC

As I understand these are all alternatives to the AP9973GH but made by another company ..Just as the SSM9973GH is....
So I could compare data sheets and try and ensure everything matches as I would prefer to buy here ..with no hassle of foreign exchange etc...

I just hope data sheets follow a similar format so I can easily compare....
Thanks Hk


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## octaneman

HairyKiore said:


> I just hope data sheets follow a similar format so I can easily compare....
> Thanks Hk



All data sheets regardless of company have the same universal format.


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## murihikukid

Hi ...I have downloaded 4 data sheets ...and to be honest they all seem to be different although they claim to be cross referenced to the 9973GH ....I just do not know enough to identify the important characteristics that have to be identical ...I have emailed SSC Asia re a NZ supplier of their products.(they may Reply)....Later I will put the old inverter on the newer board and see what happens..and have another go at desoldering mosfets...its snowing here and I am freezing.. Hk


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## octaneman

When you look at the information everything on the mosfets characteristics is important ,it all depends on the application in which the mosfet will be used. In this particular instance, the mosfet is used as a switch to turn on the inverter transformer. 

You will look at the source voltage which is 60V, 
Its maximum current which is 14 amps, 
The resistance value of the internal diode 80 Mega ohms, 
The switching on time 7 nano seconds, 
Switching off time 16 nano seconds.


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## murihikukid

Yes ..Thanks ..I will check those in particular to see if I can get a match..I have just downloaded the Data Sheet for the 40T03GP (the mosfets on the newer board ) and first thing I note is that they are a 30V rating against 60V on the original board...Hk


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## octaneman

The voltage ratings on the data sheet represent the maximum capacity of the mosfet without burning out, it does not necessarily mean that the voltage on the rail is actually 60V. You will have to power up the board and take voltage readings from drain to source to know the exact voltage across the mosfet.


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## murihikukid

OK.I am back on it...First I wonder if this will help...I have attached a photo ..In it I intend to depict the various characteristics of the various cross reference Mosfets starting with the 9973GH which I have filled in.....
I will simply fill in others in a follow up post if you decide this is worthwhile ....I just wonder if any important cross reference characteristic is missed out (I have room for another or can redo the photo to allow more)....
I presume once the main characteristics are Identified we can look at the bigger picture ...but at this stage I just want to check out aprox 5 other Mosfets for compatability
Its simply easier for me doing it this way..Thanks Hk


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## octaneman

What you've done is an excellent method to compare information on compatibility from other manufacturers. Like I said in an earlier post the mosfet acts as a switch, the closer we are to the original specs the better.


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## murihikukid

Hi...Heres the best I can do...I am worn out doing this ...Hk


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## octaneman

HairyKiore said:


> Hi...Heres the best I can do...I am worn out doing this ...Hk



Welcome to the world of electronics.

If you think this is bad wait until you come across a device that you really want to repair only to find out the components are obsolete. 

No one said its going to be easy, it is common practice that manufacturers remove their product line components after a 10 year period. Locating replacements is labor intensive,finding the right one can take weeks or months if the device is past the 10 year marker. Thats why people dispose of their devices instead of repairing them, not because its not repairable but the lack of availability of replacement parts especially in today's disposable society. 


Alpha & Omega second from the list is the best compatible component. 


Question. 

Did you receive a reply to your inquiry from standard silicon ?


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## murihikukid

Question. 

Did you receive a reply to your inquiry from standard silicon ?
No...Not Yet..I have now sent emails to Advanced Power Electronics but I do not hold out much hope ...the website says they are in Australia but when one tries to get a contact there is nothing....Yes when one tries do do a cross reference AOD444 seems to be the one that jumps up...

I have got the inverter ready to solder in ...I note none of the parts have the same numbers as the original board but I presume this is normal???
Thanks Hk


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## octaneman

HairyKiore said:


> I have got the inverter ready to solder in ...I note none of the parts have the same numbers as the original board but I presume this is normal???



Yes it is normal, the serial numbers are different so the pcb's have different component parameters. 


Don't hook up the power board to the logic board right away until you take voltage readings off the pins. Be absolutely certain that they're all there and within spec. It's a safety precaution just in case there's a voltage surge through the inverter. 

post back the pin voltages.


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## murihikukid

Hi..Well I presume it had to be tried?? Based on knowledge gained this is well short of expectations..I wonder if my Private message went through??HK


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## octaneman

Your message came through OK. 



Not good. 

You are back to square one. 

Power down the board and discharge the main capacitor. 

Start with the fuses underneath the board and test them for continuity. When your done power up the board again and probe for voltages. Start from the capacitors as you did before and move backward to the diodes on the heat sink. 

Check the voltages coming from the diode rectifier on the heat sink. Its the same procedure as you were testing them with power off, the difference this time your meter is set on voltage and you will probe for power. The diodes on heat sink have a capacity of 40V so set your meter 1 scale higher when your about to test for its voltage. Remember, the middle pin is ground and the left and right are positive. 


Use the power readings from your original board as reference.


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## murihikukid

OK...I had already powered down PLUS I did not want caught again ?? and immediately discharged the main capacitor .. its quite evident that this board is a second hand one and I presume the next one to arrive will be the same ...However they are at no cost to me..Later I intend to attack the mosfet removal on the original board and then move on to a complete analysis of the power board that I have just tested...Hk


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## murihikukid

Hi Re Mosfet removal ...This is a nightmare?? Are these surface mounted Mosfets supposed to come off ..I have removed the broken one BUT I do not like the look of the copper track under the mosfet so I will try and take a macro closeup photo tomorrow of under the Mosfet and of the area where it came off the board and will post ...With one pin broken it slid sideways and I might be mistaken but I suspect there is part of the copper track still on the bottom of it....But this may not be a problem .....it looks to me if there is a metal plate that the mosfet is built on...
What is a problem is how they are meant to come off .....In my estimation the pins (what I call Feet) have to be freed from the board ...I have tryed my ideas but nothing worked and all I have left is what I have attached ..IE threading a fine strong single strand of wire behind the foot in a loop ...apply the bolt and carefully pull the wire under the foot in an attempt to break the solder..then do the other pin......if the two pins are free the mosfet may then come off by applying the bolt to the base plate on the other side..
I hope this makes sense ....but again I welcome your comment...
Now to start checking the other board...Hk


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## murihikukid

Hi ..F100 is blown on new board... Hk


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## murihikukid

Hi..I went back and came across the diodes D102 and D103 so I took readings with the black lead on the centre pin and the red lead either side.....and got these results....As I understand and if my memory is correct I have to desolder these pins and take further readings SO I am desoldering them now..Hk


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## octaneman

Your idea to remove the mosfet makes sense but why do you have to take such extreme measures perplexes me. 

If the diodes pass the test create a wire strand fuse and solder it on the F100, remove the inverter transformer re-take the voltage readings off the pins. Do the voltages return to normal ?


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## murihikukid

To test them they have to be desoldered off the board. Mosfets are susceptible to static electricity, one jolt of static electricity and they're fried so you have to be really careful with them. 

Post #259....I thought thats what you wanted me to do..Take them off and test them? I am still having problems desoldering the diodes and I am beginning to wonder if I am the problem or if its the braid I am using....Its also a real problem now not being able to go outside in natural light to see things...Hk


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## octaneman

Yes I want you to test the mosfets but I also want you to re-take the voltages without the inverter from off the pins if the mosfets pass the test.


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## murihikukid

Hi..I think I better give up..I am just too old for this ..I cannot even keep my hand from shaking doing this desoldering of the diodes...I am losing touch here....Plus I think I may have ruined the new board ...Heres an example of what I am facing ..I decided before doing the capacitors I would do the Diodes ..I sent several hours last night trying to Desolder them ..Went to sleep and now had another go ...I managed to get D103 Desoldered so that I could get the readings required (by ensuring that each individual pin was free of contact with the track it was originally soldered too)
But D102 ....No matter what I do all 3 pins are giving me a contact reading with the track ....I have looked at each with a magnifing glass etc and there appears to be no visible contact but I still get a reading so there is still contact somewhere...Now with all my use of the Solder Sucker and the braid and I presume the heat ..I see that part of the track has lifted .....
Now with all the time I have spent on the above I could have simply removed each Diode ..Tested them and put them back with no damage in a fraction of the time ..
To carry on its got to be one board or the other cause I am getting to a stage I do not know what board we are talking about ....
Maybe when I found a blown fuse I should have put a strand wire across it and done another powered up test at the pins to see what readings I then got....Sorry about this ..Hk


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## octaneman

I can't believe what I've just red. You've invested money, energy, time, to purchase equipment and the willingness to repair the monitor. I've spent a considerable amount of time guiding you and now you're telling me that you're going to give up ?!?! But thats OK, If you are going to call it quits I need to know now.

The fault is not yours ..its mine.


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## murihikukid

Of Course..I do not want to give up ..I was not well yesterday with diabetes and really disappointed at what has happened..I know what track damage means..Whether there is enough track left I do not know ...In this instance what I call track leads nowhere ..its just a circle of copper round a hole where the pin is soldered to and could be the reason why part of it lifted...I will try and take photos and post them later as its still early morning here but pouring with rain so not much chance of my taking photos outside ...I had hoped that the board promised may have arrived by now and to be honest I just feel at this point uncomfortable emailing him...(Maybe in another weeks time)... 
I could try EBAY again ...
At this stage I know D102 is alright as its been desoldered and checked....I could take the screw out of D103 and carefully take it off the board especially when I am interested in why it is giving me continuity when all 3 pins look desoldered ...test it ..and get a better look at the track damage..Take photos and try and decide if its unrepairable....I could test all the capacitors ....then I could put a one strand wire across Fuse F100.....Hopefully by then we will know the photo results......I wonder if the diodes have to be completely soldered back on the board to get a power reading across the pins....unless I have missed something out..I have attached from an earlier photo the diode pins with an arrow to the problem one...Hk


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## murihikukid

I am getting worse at taking photos ..Heres three ..I hope the one I have marked tells the story and I can see on the Diode to the right I have lost part of the track also although there is sufficient track to make a bridge if necessary unlike the one to the left.. BTW the tracks are slightly different between boards ..Hk


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## murihikukid

Hi .Heres the tests
Diode D103
Left Pos to neg centre to Right Pos
.196 and .196
Reverse leads get 1 on each
Diode D102 same result but when I reversed leads centre to right pin ..reading never came up instantly as 1 but came down in increments to 1 like a capacitor test?? Maybe a bad DMM connection...
Capacitor s
A charged and discharged
B and C ....????? I presume they are no good..I got a reading of 00.0 on Red lead to Positive and black Lead to positive so neither were taking a charge ...Tried a continuity test and both have continuity..
D,E,F,G.H and I all charged in increments and discharged when leads were reversed..Which as I understand indicates they are all good..Hk


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## murihikukid

Here is two photos of the mosfets on the original board...You can see where one mosfet has come from ...I wonder if I have done any damage? apart from the mosfet.....
Now the second mosfet right pin is free and I did it with a loop of wire and drawing it through ..You can see the wire looped on the left pin and ready to pull it through ...once the bolt is applied...I do not think it does damage but once I get the pins free and I get get the mosfet off I will be able to see..

I did try a finer wire than this but it did not work as the space under the foot was not enough and it just resoldered itself....Then I tried a wire from one of the plastic wires that one gets in a packet of Freezer bags to tie the top with...

Its just a pity I never thought of a wire first??? Hk


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## murihikukid

Well its off ..no damage done ..the wire worked perfectly ....as you can see compaired to the one on the left..
I have shorted out some tracks in my work and I will have to try and clean that up... 

I do have a solder bolt problem..I have tried to tin it using flux and solder but my solder just rolls off the bolt in a small ball ..I wonder what I am doing wrong?? Hk


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## octaneman

For solder to roll off the bolt means the heat setting is too high, you need to turn it down a notch and clean the bolt constantly to get good heat contact. Use the solder wick to clean up the excess off the copper trace. 

With the mosfets now off you can test them with the procedure outlined earlier. Post the results of the mosfet test. 


Now, you have to make a decision which board you will repair. Take into account what you've done so far, evaluate your options and make your choice. Will it be the original or the second board ?


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## murihikukid

Hi.. The decision is out of my hands....It depends if I get any follow up to the messages I sent you in private...Remember I am one mosfet down....without a replacement I only have one board ...then do I get another as promised ,and if I do what condition it will be in..and will it be the same as my original or my newer board..so there is a few variables I have to consider..
Can you see any track damage in the photos that would render the board unusable? That is my major concern..
Is wick different to Braid? because I just do not like the braid that I was sold by the local electronic shop ( unless there is some secret in using it ) and feel that is what has contributed to track damage more so than the sucker..
I will test the mosfet I removed this afternoon within the hour...

Now I never had the problem with the turbo charged bolt that broke down on me (and has been returned) like I am having with this soldering bolt ...there was a new spare tip with it so if I can find it maybe I should put it on...The only thing I can put it down to is that the tip is not clean enough so I will look at that tomorrow ....
Hk


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## murihikukid

Hi Here are the Mosfet test readings....By your original instructions the second test is wrong?? so I did it twice but got the same result. Hk

DRAIN (POSITIVE LEAD )TO SOURCE ( NEGATIVE LEAD ) 00.2
DRAIN ( NEGATIVE LEAD ) TO SOURCE (POSITIVE LEAD ) 00.2

GATE (POSITIVE LEAD ) TO DRAIN ( NEGATIVE LEAD ) 1
GATE (POSITIVE LEAD ) TO SOURCE ( NEGATIVE LEAD ) 1

GATE NEGATIVE TO DRAIN (POSITIVE LEAD ) 1
GATE NEGATIVE TO SOURCE (POSITIVE LEAD ) 1


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## octaneman

Visually I don't see any damage to the track, but you can verify the connection very easily by doing a continuity test between the pin and the track. If there is no continuity then you need to make a bridge.

The second test shows that the mosfet behaves like a P-channel instead of an N-channel. The problem with that idea is that if it were a P-channel the third test should have given you a low resistance reading. The test shows that the mosfet is gone.


I need you to perform a similar test on the second board's mosfet to compare notes, there is a slight variation in readings but essentially the testing procedure is the same. I'm asking you to do this so that you can have an idea how different styles of mosfets behave, some are fast switching which you can turn on/off like a light switch by placing your positive lead to the gate to turn it on and then turn it off by shorting the drain and source pins with your finger. These type are turned on by current (amps) instead of voltage, you need to know which type your board has so you don't misdiagnose a good mosfet for a bad one.


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## murihikukid

OK..You want me to remove one of these Mosfets? If so ..I presume some type of compound holds them to the board or maybe its just the white stuff ..Hk


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## octaneman

Yes , remove one of them these type of mosfets are through hole type not surface mounted. These will be very easy to remove off the board by just desoldering the pins, the white stuff you can remove with iron.


----------



## murihikukid

Hi..I have not removed Mosfet yet...I have been studying soldering and bolt cleaning etc ....I do not know if I am doing the right thing but just gave the tip a good cleanup with a brass put scrub?? also I would appreciate knowing the right solder to buy as my small pack of hobby is basicly gone...I now think the bolt or the unclean tip may have been a real contributer to my problems lately...Hk


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## octaneman

I personally use MG Chemicals they carry everything under the sun for electronics. Contact your suppliers for the major manufacturers in your area.


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## murihikukid

Hi Just got out of hospital after feeling unwell..We only have Jaycar Electronics..its an Australian company and apparantly most cities now have a Jaycar franchaise incorporated into a local Electronic shop..Hk.


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## murihikukid

Hi..Maybe I am just destroying these mosfets trying to take them off ....I do not know about this soldering station and the soldering bolt and the solder sucker looks like its not working...I had a terrible job taking the mosfet off ...Completely different to what it was when I used the Turbo charged bolt before it broke down...There nothing on the DMM between Drain and source with the positive on drain so its apparantly had it...hk


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## octaneman

Unscrew the bottom end of the solder sucker and clear out all the particulates that have accumulated on the O-ring and spring and it will work good as new.


----------



## murihikukid

Hi..Yes ..I went to the Electronic Repair shop and a gentleman there checked the solder sucker for me ...He cleaned it out but it had no suction so he had some heads there and he found one to fit it and the sucker has finally got its suck back ...So the soldering bolt was next ...the tip on it is had it so I have a spare so will try it out later to see if I can tin it.....Its not new but in far better condition than the other one...I then spent hours on the internet trying to match up the tip ..Thank goodness the spare tip had a number imprinted on it XY401 so hopefully we can find them here and I will buy a few..I will look out for a 24V-48amp bolt as a spare ...Its been a real lesson for me ....Hk


----------



## octaneman

Soldering tips wear out faster when they run at the station's maximum temperatures for long periods, the solder actually corrodes the tips when the bolt is in use thats why the tip must be constantly cleaned off after every second joint soldered.


----------



## murihikukid

OK...Another board has arrived ??Thank goodness I opened the package up immediately as I am sure its not compatible..I have posted a photo but I have seen these on Ebay and I think they are for another model of monitor..I wonder what you think? ..I have notified the sender but I have probably done my dash with them which is unfortunate ...Hk


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## octaneman

I don't know why they sent you that particular board aside from the pin outs and the outputs from the inverters, from my point of view it appears that viewsonic's boards are all interchangeable. What's important are the output voltages coming from the board, before you connect it to the logic board or put power through it test the fuses with your meter make sure all are OK. If everything passes test the voltage outputs to the pins if the voltages match your original board then it would be OK to use it.


----------



## murihikukid

Hi..the Mosfets have arrived so I must get going and do the work on the boards as you require?? Hk


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## murihikukid

Hi..Heres the surface of the new board..I have found F102 and checked it but because the board is configured differently I cannot see the other fuse (I think F100 )...I wonder if you can see it ..
F200 is on the component side and is a glass fuse..and I have now found F101 beside the AC socket
Thanks Hk


----------



## murihikukid

Hi...I still have equipment problems ...The spare tip for my soldering bolt is pitted just like the original although only on its tip and I presume it has lost its iron plating ...it will not tin so therefor it will not liquidfy the solder on the Mosfet leads ...I did get one liquidfied by applying some hobby solder and applied the solder sucker and this led to another problem ...I note that with the new head that was put on by the repair shop ...the metal plunger rod that pushes through the teflon tip does not finish flush with the tip (like it did on the original head)... with the plunger pushed in and locked there is an aprox 3/16 inch gap to the teflon tip...
Now I do not know if this is crucial to the solder sucker to work ..if it is... it may well be that the teflon tip could be shortened by carefully cutting 3/16 inch off it...or maybe I should just buy another sucker that I can get tips for ....

After all I cannot do anything with my soldering bolt til the new tips which I know have been posted arrive....I am also still checking daily for a 25v 48W bolt as an option but while 6 weeks ago there were several there is now nothing but hopefully soon something like a Weller will be listed..Hk


----------



## murihikukid

but hopefully soon something like a Weller will be listed..Hk

Hi..Doing a Google search it may well be that the soldering iron I have is the only one made ( 25v 48W ) for my soldering station..Hk


----------



## murihikukid

Hi..I thought it might help with a schematic of the pins...and the markings on the new DAC- 19M009 board..I have come across info on Google that does state that the board is compatible with a VX 2235wm-5...Hk


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## octaneman

Its best that you buy yourself a new solder sucker and wait for the new tips for the bolt, when they break down I throw them away its not worth the effort in fixing. Soldering components with damaged gear will scrap the board, I learned that lesson the hard way please don't make that same mistake. 

What you can do in your free time is practice taking readings off the new mosfets so in the future if another repair job comes up, you will know what good readings on mosfets look like on the meter. It may not necessarily be monitors, it could be computers or any electronic appliance that has a switching power supply. Always keep in mind that mosfets are susceptible to static electricity and everything will be OK. 


Question: 

Have you taken voltage readings off the pins from the new board ?


----------



## murihikukid

Hi.. Actually the sucker does work ..I can put my finger over the nozzle ,release the plunger and then my finger and its definately got plenty of suck in it....The bolt tips are the problem.....
So I have just powered up the new board and
heres the readings ..I have only done the two....
the 13.8V pin is reading 14.29V
the 5V pin is reading 5.04V

Re Mosfets ..Yes I take your point re static electricity but what is the best way to deal with this...Use Rubber gloves ?? 
Hk


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## octaneman

To deal with the mosfets wear a ground strap. 

With the voltages being present the board should be able to power up your monitor, you should hook it up to the logic board and find out if it works.


----------



## murihikukid

I have hooked up the new DAC- 19M009 board ...Now I get Blue on the centre power switch under the screen but thats it...I presume the backlights should go on which they don't...I will now try the new DAC-19M010 board received today..Hk


----------



## murihikukid

I will not make an electronic technician...I have done the unthinkable ...I tested the new DAC-19M010 fuses and they were OK ..I then went to test the power at the pins .I did put a folded piece of cardboard round the first 3 pins so that I could rest my lead against it while taking the voltage test (14.2V )...I then did the same round the first four pins to get the next pin..It came up at 5.2V and I got an arm shake and it slipped off but must have shorted it out ....because when I retested it I had nothing ...I depowered the board and rechecked the fuses and F101 has blown... I am so upset..I should have just folded another piece of cardboard and put it round 6,7,8 pins leaving the 5th pin able to be tested and if my lead slipped it would not have touched any other pin....
So I am at a complete standstill..With no soldering equipment I cannot do anything ...I do have a fuse on another board ...I presume these can be easily desoldered ...I am really sorry about this ..I just should have been more careful..

I am also wondering if early on I did any damage to the backlights ...They originally went ...
Hk


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## murihikukid

Just thinking..Fuses can have different strengths ..Is this measurable on my DMM cause I am thinking that its highly likely that the other surface mounted fuses are maybe the exact same fuse which would give me another option where I "grab" a fuse from if I cannot get one...from the repair shop...Thanks Hk


----------



## murihikukid

Sorry ..I now find the fuses have their value written on the top ..I keep learning.? And F200 is the same value as F101....although no M or W is actually listed on the value list I have found online....Hk


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## octaneman

Circuit Protection, Fuses, Thyristors, Automotive Circuit Protection - Littelfuse.com


This site has a comprehensive data on all types of fuses including their datasheets , if you are looking for a specific value for a surface mount fuse you should be able to find it.


----------



## murihikukid

I presume once the tips arrive I could use a one strand wire for a temp fuse...I also noted that the original board and another F200 and F101 had a S on them ...Two other replacement boards has F200 and F101 with what I presume is a W on them..
I have tried to look through the fuses in the link sent in your previous message but its all double dutch to me ...This is where a schematic of the board would probably come in handy as I presume it would have info on exactly the strength of the fuse ...
On the photo attached I have circled both F200 and F101 with an S on them....I am presuming these are interchangable..Hk


----------



## octaneman

Surface mount fuses that are typically marked with the same marking have the same values but its not an exact science. However, surface mount fuses do follow a pattern of amperage ratings when they're marked with letters even from different manufacturers but their characteristics are completely different.

Example: here's a list of amp ratings for surface mount fuses that have a letter as a prefix. 


D = 0.25A
E = 0.375A
F = 0.5A
X = 0.68A
G = 0.75A
H = 1.0A
J = 1.25A
K = 1.5A
L = 1.75A
N = 2.0A
O = 2.5A
P = 3.0A
R = 3.5A
S = 4.0A
T = 5.0A

Note; Solder a strand fuse to the DAC-19M010 board and try again.


----------



## murihikukid

Yes..I found that list of Amp ratings but there was no W...then I happened to check the original board and saw that instead of a W it had an S so I thought maybe 4.0 Amp fuse is the one and I could use a W or a S....I hope the tips are not too far away ..I can do nothing without a soldering iron...Hk


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## octaneman

Are both your tips that far gone that you cant use them ? Have you tried using emery cloth to sand the carbon off the tips ?


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## murihikukid

I have used Brass Scrub to clean the one that is pitted extensively .The other is only pitted for about 1/8 inch of the point while the rest looks in good condition ...I thought that once they were pitted that was it but I can try some light emery paper and then see if I can tin it...Hk


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## murihikukid

Hi ..Tips have arrived ..Now I have to decide what to do ...I will remove the Mosfet first and test it as you asked....You may wish to comment on the fuse problem and whether I should remove one of the F101 or F200 SM fuses from another board and put it on the brand new board ...I presume there may be a technique to do this seeing they are small..Thanks Hk


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## octaneman

Don't remove the F101 fuse just yet use a strand first and re-take your meter readings to see that it doesn't blow. If all goes well connect the board to the logic board be sure that the voltages are OK and your monitor should fire up. 

To repair your original board with the new mosfets you will remove the excess solder off the board with your solder wick, make sure the old solder is completely off the copper trace. When you are ready to place the mosfets apply solder flux liberally to the board and the mosfet legs first then pre-heat your iron to the point where solder liquefies. Tin your tip with solder first and then apply it to the mosfet and its soldering points. The solder should liquefy around the connection, do one leg at a time and do not leave your iron on the mosfet longer than 60 seconds. The end result should be a solid solder connection.


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## murihikukid

Hi...I have in total 4 boards The Original board being #1...We know the Transformer Inverter is burnt out on board #2...so unless the Transformer Inverter turns out to be OK on #1 ...we have no replacement ...cause #3 has the dual Transformer Inverters and #4 is the brand new board with the blown F101....

Now by what I understand from past posts.. by installing two new surface mounted Mosfets on #1 ..we should be able to verify if the transformer Inverter is actually OK or not..

I just purchased 4 soldering bolts along with a boxful of solder and tinning accessories...it went for more than I expected but with solder etc the price it is I will sort out what is OK and just put what is left back up for auction and hopefully get most of my money back..

One final question ....say a 25V 50W iron came up for sale ..would the 50W preclude it being used on my soldering station which is 48W....
Thanks Hk


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## octaneman

If I were in your place this is what I would do. 


First; 

Board #1 The Original. 

This is the board we are going to work on first because you have the new mosfets which you will install. It is preferable to get this board going because we have already have a replacement fuse and have done all the diagnostics on it. 

Second;

Your back-up board will be board #4 with the burned out fuse, it is a quick repair there's nothing major (so far) because everything appears to be intact. You will repair it by soldering a strand fuse to it and then check the voltage output from the pins. Once the voltages are verified coming out of the pins you can either keep it as reserve, or re-sell it at auction to recover some income. 


Third;

Board #3 with the blown inverter you can use as spare parts because if i'm not mistaken it also has a duel inverter transformer wich you can swap on board 4 if the need arises.




HairyKiore said:


> Now by what I understand from past posts.. by installing two new surface mounted Mosfets on #1 ..we should be able to verify if the transformer Inverter is actually OK or not..


True. But you are going to verify voltages before you assemble everything together. 




HairyKiore said:


> One final question ....say a 25V 50W iron came up for sale ..would the 50W preclude it being used on my soldering station which is 48W


Your soldering station has more than enough juice to to do the repairs, an extra 2 watts wont have a huge effect if the soldering is done properly.


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## murihikukid

Ok..But I have some reservations here cause I think we are getting mixed up..

so can we go back and look at the original #1 board first..

I have posted a photo what I see as a problem and do not know if it can be worked around?? As you can see where I took the mosfets from ..the one on the left I believe I have shorted out the tracks ....can it be fixed cause if not surely the original board is only good for parts...

Once I get your analysis on this we can work out what options we have left.

Now re my Question re Soldering Iron ....I thought that if a 25V 50V soldering iron became available and tips could be easily purchased here for it ..that would be better than sending over to Germany for tips for the 25V 48V Iron that I have..it was nothing to do with the power of the iron...Thanks Hk


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## octaneman

The left side can be fixed by applying your solder wick to clear up the bridges made when you removed the mosfet. Set the heat range where solder liquefies then apply a little solder flux to the area affected, slowly move around the tracks where it is bridged with your solder bolt you should be able to clear it out without a problem. 



HairyKiore said:


> Now re my Question re Soldering Iron ....I thought that if a 25V 50V soldering iron became available and tips could be easily purchased here for it ..that would be better than sending over to Germany for tips for the 25V 48V Iron that I have..it was nothing to do with the power of the iron...Thanks Hk



To cut down on delays and extra cost by buying soldering equipment with those little extras within your in your immediate area is completely understandable, because I'd do the same thing especially if you are in a location where accessibility to top of the line gear is limited.


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## murihikukid

OK..I will clean it up where both mosfets go after I have tinned my new soldering tip...Then I will carefully install two new Mosfets unless you want me to put the original Transformer Inverter on first cause it is on board #2..Hk


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## murihikukid

Right..I tinned my new tip exactly from a website video and tried to clean everything with the braid...Well to be honest I am having no luck with this braid even after watching a video on how to use it.....I just cannot seem to be able to get it to do what its supposed to and it sticks and I really risk doing damage ..I increased the bolt heat from 220 up to 300 degrees but no better....
However I tested the Mosfet mounts with the tracks marked yellow (which do not seem to supply anything ) and I got continuity ....
So I tested the new board and it was the same yet I just do not see how this could be happening...So I might be wrong but it makes no difference if there is contact where I put the arrow on the previous photo posting PLUS I really cannot see any solder between the Mosfet mounts and the tracks although it certainly looks like there is a connection....going by appearance???
Also
I have circled in blue which I believe are two mini bridges ..I will cross check these against the new board...

So thats where I am at ..I am not going to risk putting the new mosfets in til I get your OK....Hk


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## murihikukid

OK..I now see where I have made a mistake ..I took the solder as a track whereas they are on the same copper on the board?? If you get what I mean ..I need to clean my glasses and clearly identify the copper etchings ..Hk


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## murihikukid

Remember I had one Mosfet to take off board #2 and test....Well I got it off and all tests were 1....So I just do not know...This means both mosfets from that board are no good ..I do not know if I am blowing them taking them off or whether they were already blown by the burnt out Transformer Inverter...I do not know how to hold them or anything so it could be me...
I even tryed to remove F101 fuse but failed ...Now I think I have ruined it ??

The problem is desoldering ...Now I have done this in the past without a problem yet now its one thing after another...

I have watched videos re desoldering and nothing I have works like the equipment in these...and that includes the bolt ,the wick and the sucker ...I am sure these boards have something sprayed on them which makes the solder difficult to liquidfy ..Its just the way the solder reacts when I put the iron on it ..
I am at a point that I want to find out if the monitor will actually go and the only way I can do this is put a one strand wire fuse across the Fuse I blew on the new board and then hook it up to the main board and see what happens..then I can go back to trying to get one of the other boards going..

I predict I will get a blue light at the off/on switch ...but what does that mean??...surely more than the blue light comes on when the power switch is on..Should not the backlights light up?....Hk


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## murihikukid

OK..??? Seems I have to auction off my useless equipment....IE Solder Sucker...So have done some research and the EDSYN-SOLDAPULLT DS017 seems to be very popular with good reviews...I checked Ebay and found one with free shipping which makes a real difference in price ..As usual its in China?? 
What do you think?? Have you heard of this sucker ..Thanks Hk. 

EDSYN SOLDAPULLT Desoldering tool Hand Pump DS017 | eBay


----------



## octaneman

HairyKiore said:


> OK..??? Seems I have to auction off my useless equipment....IE Solder Sucker...So have done some research and the EDSYN-SOLDAPULLT DS017 seems to be very popular with good reviews...I checked Ebay and found one with free shipping which makes a real difference in price ..As usual its in China??
> What do you think?? Have you heard of this sucker ..Thanks Hk.
> 
> EDSYN SOLDAPULLT Desoldering tool Hand Pump DS017 | eBay



Yes I have; allot of techs use it.


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## murihikukid

OK...On the New board I have soldered a one strand wire across F101 ...and I get 14.3v and 5V ( I cut a cotton bud in half and used the shaft pieces to push over pins either side of the pin I was reading ?? so no shorting out this time.) 
I then put the Power Board on the monitor ..and powered up...
First thing I noted was I had a beautiful BRIGHT blue light at the on switch but sadly if this is an on /off switch ...it does not work cause no amount of pushing with my finger nail can switch it off...I have read about how difficult these are on this monitor...
So
Should have the monitor fired up?? IE Backlights ....Thanks Hk.


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## octaneman

The monitor should have fired up. Do you see the back lights on when you powered up the board ? If not you will need to check the CCFL lights. 


The CCFL lights on your monitor are like fluorescent tubes only allot more thinner and fragile, if you see a black spot on the contact ends of the CCFL tube its gone.


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## murihikukid

I am Googling now trying to find out where the lights are? and how to get at them..Hk


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## octaneman

There's a way to test the CCFL lights without tearing it apart. Disconnect all the plugs that go to the CCFL lights except one your monitor has 4 CCFL lights. Power up the monitor wait until the indicator light turns on. Press the on/off switch and look at your screen it should flash for a second or two. Do the same procedure to all the CCFL lamps to isolate which one may be burned. If you get no response from the CCFL tubes either the tubes are burned out or there's a problem with the connections/ transformer/drivers. 


Question:

1) Are you sure that the connections to the on/off switch are OK ? 

2) If you gently press with your finger on the LCD screen with power on does the panel illuminate slightly ?


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## murihikukid

Hi..I presume these are the plugs that go to the CCFL Tubes?
...Its the middle of the night and I decided to reply to your response so I can try and sort this out ..I will have a good look at the on/off switch in the morning....Could the switch be permanently jammed in the on position if the frame is just not seated properly against the circuit board ..I just feel there is something wrong here...the on switch does not respond or feel like a switch ...Plus the blue power on light is really several times brighter than I have ever seen it..it really surprised me...Unless both the orange standby and Blue are both on ..if that could happen..

When I first started working on the monitor the back lights went ?? I just hope I have not shorted them out or done something I should not have... ...Hk


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## octaneman

When you powered up the monitor do you see any of the backlights turn on ?


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## murihikukid

octaneman said:


> When you powered up the monitor do you see any of the backlights turn on ?


If you are referring to since we started working on it ...NO...Hk


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## octaneman

On post #366 you said that the indicator light is on but your screen was poorly positioned and the on/off switch was jammed and didn't "feel" like a switch. 
What did you mean by that ?


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## murihikukid

I have just done a test of the on/off switch...I apparantly have no blue ,a dull blue and a bright blue ?? I see how the mechanism is supposed to work but as I see it ..it does not work?? Its supposed to make contact with a small on/off switch on the circuit board ??Whether it does or not I do not know as the only way I can tell is if the (is it LED light) goes out ...and I have used my fingernail etc and nothing changes....I presume if I took the circuit board off its pins and gave the switch one push and put it back on again I would have the unit to be off ..
As long as i have a bright blue I presume the power is on..I just do not know what the dull blue signifies ...in the past when I have thought it was powered up when the dull blue light was on I now assume it wasn't ..To be honest I do not like this switch panel if I could call it that and I do not think I should touch it again...and that rules out the on/off test you wanted me to do unless I do it via removal of the power chord or by switching my Powerguard on and off...
I presume the photo are the wires to the plugs that you want me to unplug in post 365 (am I right that the Transformer Inverter transforms the correct power to drive the CCFL tubes...) Hk


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## octaneman

> presume the photo are the wires to the plugs that you want me to unplug in post 365 (am I right that the Transformer Inverter transforms the correct power to drive the CCFL tubes...) Hk



Yes, test the CCFL plugs one at a time just have your power guard handy to turn it on/off. Remember, when you turn the monitor on there will be a bright flash for a brief moment telling you that the CCFL works for that particular plug.


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## murihikukid

octaneman said:


> On post #366 you said that the indicator light is on but your screen was poorly positioned and the on/off switch was jammed and didn't "feel" like a switch.
> What did you mean by that ?


Hopefully the just posted post will explain ...I stress that this mechanism I presume is just meant to have small pressure at its centre..IE where the blue light is ..this pressure should move a small knob on the plastic section against the on/off switch on the circuit board and change it from on or off depending on what it was on..the only indication for me if anything is happening is the LED light .the whole mechanism is so unstable .....one can see this if one unclips the circuit board and then pushes the on/off switch with nothing behind it..
As in another post..I have read reference to the power on/off switch and its stability in my Google readings...

Now I am working upside down working the power on/off switch IE I have the monitor face down on a towel on a table ..so i have to lift it upright to pressure the switch..HK




Do you want me to take some photos


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## murihikukid

octaneman said:


> Yes, test the CCFL plugs one at a time just have your power guard handy to turn it on/off. Remember, when you turn the monitor on there will be a bright flash for a brief moment telling you that the CCFL works for that particular plug.


ok ..Back in a few minutes ...Hk...


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## octaneman

Just a thought. 

Have you hooked up your computer to the monitor ? Remember that its not the original board so the signaling has changed somewhat, the CCFL may need a signal from the computer port to fire up.


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## murihikukid

Ok..No I have not hooked it up to my computer....
I hope this makes sense ...but I can only tell you what happens...Because its nearly dark I switched the light off in my workroom and left the light on in the adjourning room just to get minimal light...I wanted to see if I got anything from the monitor.
So I set everything up so that I switched on/off via the PowerGuard and had one CCFL plug connected...I held the unit upright 
When I switched the unit on I had a dull blue power switch so I switched the power off and switched it back on ..What happened was for an "instant" the LED light went bright Blue and then reverted back to the dull blue...So I wonder if this indicates anything...Hk


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## murihikukid

I have now done tests on each CCFL by switching on/off ...I have not had a bright Blue LED Power On light again ...just the dull blue LED ....I have switched on/off each CCFL several times ....but just get the dull blue light when I put the Power on...

I will now hook the monitor up to my computer and see what happens... Hk


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## octaneman

Blue light = Power on 

Orange light = Active off ( Stand by mode) 

Dark blue = Power off


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## murihikukid

Yes I know ...A Bright Blue light must signify Power on ...Orange Light ??? Well I have never seen it??... Dark Blue ...I presume this must be a light that appears when I plug into Power cause when I depower it goes out ...So does this mean that when the monitor is plugged into power I get a Dark Blue Light and when it is then Powered on I get a bright Blue Light ...

I have now connected the monitor to the computer and powered everything up...there is no change to the monitor ..I just get a dark blue LED which clearly tells me it is not powered on..

I presume now I try to get it into Power On Mode by manually pushing the on/off switch behind the circuit board ??? and switching everything back on..Hk


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## octaneman

HairyKiore said:


> I presume now I try to get it into Power On Mode by manually pushing the on/off switch behind the circuit board ??? and switching everything back on..Hk


Yes.
You mean you've been trying to turn on the monitor without pressing the switch manually ?


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## murihikukid

OK..I manually gave the power on switch a push ..put the Circuit board back into place and powered it up...I had the bright blue power on light ....when I powered up the Computer I lost the Bright Power on Light ...in fact it gives a flash that one can hardly see before reverting to a dark blue..So I do not know how to hold the monitor in full power on with the computer connected... But I can do some further tries and see if I can work something out...so that the monitor holds on to Power On.. Hk.


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## murihikukid

octaneman said:


> Yes.
> You mean you've been trying to turn on the monitor without pressing the switch manually ?


Yes...


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## murihikukid

OK ...Simply because the Frame mechanism clearly is not working ..IE I cannot switch the unit on by the proper mechanism ....I can only see one alternative here ...Is there a safe way to have the circuit board unclipped from its framework and hanging free by its ribbon connector...I will then have direct access to the switch ...I do not want to electrocute myself ..I could use some sticky tape to keep the circuit board as stable as possible while I work the switch manually with a finger...Then hopefully these problems will be able to be worked out..Hk


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## murihikukid

octaneman said:


> Yes.
> You mean you've been trying to turn on the monitor without pressing the switch manually ?


I wonder how my answer IE YES...... got in your message ...I must have done something wrong ...Hk


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## murihikukid

OK..I have sticky taped the circuit board with the 5 switches on it to the top of a small oblong plastic drawer that one has in a unit for storing resistors etc in...that is taped to the frame..The five switches are facing upwards and I now have ready access to the power on switch and as I see it I can just touch with my finger to change between modes (safely with a rubber glove?)...Sorry I do not have a photograph...but I believe now I can do some meaningful testing then later I can try to discover why the mechanism on the frame is failing to change modes on the power switch ...I sure hope this works..Hk


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## murihikukid

OK..What do I know?? I wondered about how the mechanism got the blue light ..I thought it must be from the frame mechanism itself but I saw no wires??? ..but now I see its apparantly not ..The blue light is coming from the circuit board ...So its not the mechanism ..the problem is within the unit probably in the power switch because operating the power switch directly by my finger is getting the same previous results .....I presume on the other side of the blue light aperture there is another and I presume this is an orange light and it should come on at some stage ....I DID get the bright Blue Flash ?? It hit me so bright I did not even see where it came from but as before I presume this is the full power on light..


SO I turn power on at the Power Guard and a small blue light illuminates on the circuit board ...I push the switch and nothing changes THATS IT ....As I understand by pushing this switch it should go into an orange light mode or a full Power On mode ..

So hopefully this alerts to another problem in the unit?? Do you want photos ..I can try and get my camera operating ..(I still have not found the Charger??)

Thanks Hk


----------



## murihikukid

I managed to get a photo...You can see how I bent back the Keypad circuit board ribbon over a Plastic tray so that the switches are all accessable and used Elastoplast to keep everything reasonably static...
I have also posted a small photo of the power on/off with the two apertures marked in yellow ...I have done a lot of searching but come up with nothing about what is happening here ..I guess its a case of the unit not powering up...
If its the Keypad circuit board I may be able to get one from the distributer here..but the ribbon goes to the main board and if the problem is there ?? well surely that must be of real concern...Hk


----------



## octaneman

A few posts back you tested the OSD board where the on/off switch is and it was OK. My immediate concern right now is the backlights. When we began the diagnostics the backlights were turning on even when you had the resistor fuse connected on the original board. Right now as it stands the backlights are not turning on even with all the voltages being present with board #4. There is that possibility the logic board may not be compatible with the main power board because of the signaling process and I'll tell you why. 


For the backlights to turn on the inverter transformer sends out a high voltage in the range of 1200 to 1400 volts D/C from the inverter plugs to the backlights. The inverter transformer cannot produce these high voltages on its own, so the power board has been incorporated with an oscillator circuit. The oscillator gives out pulses to the inverter transformer which causes the magnetic field within the transformer to collapse producing the high voltage.

Think of it this way; the oscillator acts like contact points in a distributor ignition system sending a high voltage spark from the coil to the spark plugs. With board #4 it is clearly not happening, because logic says the backlights should have fired up the moment you connected the power cord to the wall. If the original board was connected I'm 100% sure the monitor would have fired up the first shot. 


I don't believe for a moment that there is a problem with the on/off switch's OSD board because we clearly tested all the switches and they passed with flying colors. The immediate problem is the backlights and its connectors to the plugs. Our first priority right now is make sure that no backlight has been burned out, which means you need to do a visual inspection of the CCFL's first and perform a continuity test on the inverter wires to the CCFL junctions to rule out any broken connections from swapping power boards.


----------



## murihikukid

A few posts back you tested the OSD board where the on/off switch is and it was OK. 

Just one correction ..?? I thought it was OK because how did I know that when I plugged the unit into Power the Power Switch turned a blue which I took as Power On..I now know I was all at sea ..that what I saw .. I now know as "soft Power" and nothing compered to the bright Blue "Power On" light which I had never seen til yesterday...Hk


----------



## murihikukid

A few posts back you tested the OSD board where the on/off switch is and it was OK. 

Just one correction ..?? I thought it was OK because how did I know that when I plugged the unit into Power the Power Switch turned a blue which I took as Power On..I now know I was all at sea ..that what I saw .. I now know as "soft Power" and nothing compered to the bright Blue "Power On" light which I had never seen til yesterday...

So in reality the unit has not been Powered Up..for me to see anything..?

The #4 Power Board is as far as I can tell exactly the same as the original #1 board....however if you want me to get the Original going I am more than happy to do this ...My real concern is the new mosfets....I just need to ask a couple of questions re the handling of the mosfets as I want to ensure these are fully protected...EG I wear my anti static wrist band ..do I just ground myself to the board or something else via the alligator clip..Once the mosfets are correctly soldered in ..the rest I see as straight forward...as we basicly just have the Transformer Inverter to desolder from board # 2 back to #1...and do the tests required along the way...
Hk



What I'd like you to do is inspect the CCFL's before doing anything else so there are no more surprises. Then we'll work on the original board installing the mosfets and testing out everything before powering up the board. 

For the mosfets the wrist band ground should be ample protection against static and your work bench cleared of debris.


----------



## octaneman

HairyKiore said:


> A few posts back you tested the OSD board where the on/off switch is and it was OK.
> 
> Just one correction ..?? I thought it was OK because how did I know that when I plugged the unit into Power the Power Switch turned a blue which I took as Power On..I now know I was all at sea ..that what I saw .. I now know as "soft Power" and nothing compered to the bright Blue "Power On" light which I had never seen til yesterday...Hk





Ok, but on the original board the backlight still came on even when there was nothing showing on the LED indicator.


----------



## murihikukid

Sorry..I just cannot recall if there was anything on the LED indicator or not..I do recall that the backlights went off and on and off and I have been hoping ever since that I never shorted anything back then and blown them..I have always wondered about the Power switch and how I always saw what I would describe as a feeble blue light ...
Do you want me to get the original up and going ....as I understand via Google that its quite a job to check the CCFL tubes...hk


----------



## octaneman

HairyKiore said:


> A few posts back you tested the OSD board where the on/off switch is and it was OK.
> 
> Just one correction ..?? I thought it was OK because how did I know that when I plugged the unit into Power the Power Switch turned a blue which I took as Power On..I now know I was all at sea ..that what I saw .. I now know as "soft Power" and nothing compered to the bright Blue "Power On" light which I had never seen til yesterday...
> 
> So in reality the unit has not been Powered Up..for me to see anything..?
> 
> The #4 Power Board is as far as I can tell exactly the same as the original #1 board....however if you want me to get the Original going I am more than happy to do this ...My real concern is the new mosfets....I just need to ask a couple of questions re the handling of the mosfets as I want to ensure these are fully protected...EG I wear my anti static wrist band ..do I just ground myself to the board or something else via the alligator clip..Once the mosfets are correctly soldered in ..the rest I see as straight forward...as we basicly just have the Transformer Inverter to desolder from board # 2 back to #1...and do the tests required along the way...
> Hk.






What I'd like you to do is inspect the CCFL's before doing anything else so there are no more surprises. Then we'll work on the original board installing the mosfets and testing out everything before powering up the board. 

For the mosfets the wrist band ground should be ample protection against static with your work bench cleared of debris.


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## murihikukid

the wrist band ground???
Anyway have you any instructions on how I get to the CCFL's to inspect them...Hk


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## octaneman

On page 19 post #365 I've posted an exploded view diagram of your monitor, there should be something in there that should help you with the disassembly.


----------



## murihikukid

Thanks


----------



## murihikukid

Hi..Are you still happy to carry on with me??.... I have the monitor completely disassembled except for the glass panel which I understand 'Must" have the CCFL Tubes attached to it...As I see it I have to unplug the inverter wires and peel away the alloy tape holding the wires to the metal framework ..there is also a small piece of alloy tape in the centre top and bottom that holds the glass panel in position so they have to be peeled off...The Glass does have a sheet of acrylic between it and the metal frame.....
There is nothing else that holds it to the frame so once I peel the alloy tape the whole glass panel should be left sitting face down on a towel covered appropriate cardboard box when I lift the steel frame and hopefully all the CCFL tubes are there to be visibly inspected ..And to carry out the continuity check that you required..Hk


----------



## octaneman

HairyKiore said:


> Hi..Are you still happy to carry on with me??.... I have the monitor completely disassembled except for the glass panel which I understand 'Must" have the CCFL Tubes attached to it...As I see it I have to unplug the inverter wires and peel away the alloy tape holding the wires to the metal framework ..there is also a small piece of alloy tape in the centre top and bottom that holds the glass panel in position so they have to be peeled off...The Glass does have a sheet of acrylic between it and the metal frame.....
> There is nothing else that holds it to the frame so once I peel the alloy tape the whole glass panel should be left sitting face down on a towel covered appropriate cardboard box when I lift the steel frame and hopefully all the CCFL tubes are there to be visibly inspected ..And to carry out the continuity check that you required..Hk




I'll be here in any way I can to help you fire up the monitor no matter what it takes or how long. There are allot of people watching this thread and we do not want to disappoint them. 

When CCFL tubes burn they burn exactly on the edges where the socket are like fluorescent tubes. If you see a dark patch on either side of the CCFL then its gone. Your monitor has 4 of them which run across length of the LCD screen or could be in a squared pattern. The CCFL's are very delicate so when you take them out be gentle with them, don't force anything or else they'll shatter on you.


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## murihikukid

Well if there is a lot of people watching...taking the Monitor apart especially when one has never seen inside one previously to me was a mine field....I was not going to blow everything so tried to get info on every step ...I was lucky cause every step I worked out by first closely inspecting round the frame turned out to be correct although the acrylic panels surprised me..Plus I never lifted anything apart from the metal frame ..I let each part drop from the monitor??..the last step has got me concerned because I expect to see the CCFL's fully exposed when I remove the glass panel/screen ....so I am wondering do they actually require removing..
i will no doubt know in an hour...Hk


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## murihikukid

Ok..Its a pity its not daylight to take a photo as I am at the final step.. the metal frame is completely off and I have only a glass screen with an acrylic backing....Along the top and bottom I have what looked like ( on first appearance to me ) a Chrome Metal 3/4 square Beading pushed over the edge of the glass and backing acrylic ...but now I presume/know that these are indeed the CCFL tubes that I have been looking for...
I will wait till daylight so as I can carefully inspect and take a photo.....
I wonder if these CCFL tubes run the full length (top and bottom)of the glass screen as they appear to do .or is there 2 shorter ones top and 2 bottom??that connect in the centre..I presume one has to carefully move them sideways off the glass screen evenly so no bending pressure is applied ..I would welcome comment on this as the worst thing that could happen is if I damage anything ..I am hoping the tubes are alright cause goodness knows if I can get replacements here...Hk


----------



## octaneman

Some CCFL holders usually have tabs at the end of each molex connector to keep the bulb in place. Unfortunately different manufacturers use different methods to secure their CCFL's. It is difficult to see how viewsonic has the CCFL's held down even with the exploded view diagram.


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## murihikukid

OK..Heres some photos taken in the bathroom ...Not as good as I would get later in Daylight but you may see something of interest...In every photo the glass is underneath so the metal frame with the Power Board etc actually sits down on what you are seeing..Hk


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## octaneman

The bulb is clearly visible on the top frame.


----------



## murihikukid

OK..I will take one side off ,and check it and put it back on before I do the other side ...One Question ....In an Earlier posting you said "do a continuity check"...do I just do this with my DMM leads to the wires coming from the bulb...Thanks.

PS..At long last I have seen them ..I have the first one off so as to photograph as just in from the each end (1/4 inch) there is a darker ring which will hopefully show in photographs .


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## murihikukid

Hi...Here they are ...This are all of the first two tubes..Hk


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## octaneman

Now that you have the CCFL's out you can do a resistance test on the bulb. Set your meter on 20M ohm scale connect your leads as shown on the pic and take readings. The bulbs have high resistance a good bulb will read on your meter for a second or two this will show a good bulb. If the meter does not show any readings bring your meter to a higher scale. If the meter shows infinity either the bulb is burned or the wires are open. 



The second test you will do is to connect the CCFL's to the inverter molex connectors one connector at a time. You will power up the board and see if the bulbs initially flash ( just like our previous test). Be very careful not to touch the bulb because it will get hot or any exposed connections because its high voltage. If it flashes even for a second the bulb is good.



Post your meter readings on the CCFL's


----------



## murihikukid

OK..There are 2 tubes top and 2 bottom ..At this stage I only have one pair off .....I have Two Molex plugs Pink/White and Blue/black....am I correct in assuming I can only do the resistant tests via the molex plugs with my DMM..Probably by inserting something in the + and - of the plug that will enable me to clip the DMM lead too....So each molex has a positive and a negative ...Can I please know what are the positive colours...

Re the second test ..Just so I have it exactly right ...I have my Power Board setup by itself ...on a towel ..I connect a tube and power up ..hoping to get a flash....I repeat on each of the other 3 tubes...Thanks


----------



## octaneman

HairyKiore said:


> So each molex has a positive and a negative ...Can I please know what are the positive colours...



It doesnt matter which way you connect your leads because you're doing a resistance reading. 




HairyKiore said:


> Re the second test ..Just so I have it exactly right ...I have my Power Board setup by itself ...on a towel ..I connect a tube and power up ..hoping to get a flash....I repeat on each of the other 3 tubes...Thanks



Right on.


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## murihikukid

OK..Getting into it now..I have a problem..First 20M resistance is the highest reading I can take on my DMM...I tested one tube and got a 1. reading ...on the second tube I got an incremental reading as like charging a capacitor til it finished at 1.
I presume this is not good? Hk


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## murihikukid

Hi..I just wonder if I am doing this right.I have two single strands of wire thick enough to put up each connection on the molex plug ....I then clip on one of my DMM leads to one wire and take a reading by applying the other lead to the other wire...I have now done all 4 molex's and I get 1. on every one..
I have also done a continuity test on all molex's/bulbs ...There is no continuity...Hk


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## octaneman

The second tube is OK but not the first tube. 

You can range your meter settings from continuity to the highest scale to fully cover the entire resistance spectrum when a bulb gives off questionable readings. Keep in mind the CCFL's run on high voltage from 1200 to 1400 volts so its internal resistance is quite high. Infinity readings (1) on the bulbs means the filament is gone theres no contact.


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## murihikukid

Hi..I do not think any of the tubes go ...I conducted your second test on each of the 4 bulbs individually except one...because by putting wires in it to do the resistance test I must have somehow damaged the plug cause it would not push into an inverter socket...
However I never got a semblance of a flash from any of the tubes ...so unless they were not being powered by the inverter they are all gone...???I presume you agree....also I presume I am the culprit ..early on I did not know half the time what I was doing so no doubt did something that shorted them out ...I know that they did go when I started fiddling around with the Monitor..
I will contact the agent and see what the story is re the purchase of new backlights ....Do they come as a twin bulb unit ?? Hk


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## octaneman

HairyKiore said:


> Post #408
> 
> on the second tube I got an incremental reading as like charging a capacitor til it finished at 1.
> I presume this is not good? Hk



Did only one tube test like a capacitor ? Its what you are supposed to see on the meter.



HairyKiore said:


> Post #408 I have now done all 4 molex's and I get 1. on every one.


Did you get 1 on every resistance scale ? You have to be absolutely sure that infinty is present through out the whole spectrum to pronounce the bulb dead. 




HairyKiore said:


> However I never got a semblance of a flash from any of the tubes ...so unless they were not being powered by the inverter they are all gone...???


Not necessarily, the power board is giving out the +13v to power the inverter transformer, on many LCD screens with multiple CCFL's they are connected in series which means that if one bulb is burned the remaining CCFL's will go into shutdown mode as a safety feature. The best way is to connect all the CCFL's to the inverter and visibly see the initial start-up flash. Remember, the flash will appear for a mere second or two even if it appears dim.


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## murihikukid

> Did you get 1 on every resistance scale ? You have to be absolutely sure that infinity is present through out the whole spectrum to pronounce the bulb dead.


Thats from Continuity right through the scale to 20M on my DMM??

I will redo everything..in the morning as its the middle of the night here and I have just woken up and noticed your post....
BUT
I did see something that puzzled me ...Now with a small wire pushed into each contact on the molex plug and with a lead on my DMM clipped to one wire by an alligator connector wire .. I then touched the other wire with the other lead of my DMM....but if I happened to accidently touch both my DMM leads together while trying to get a reading I then got an incremental reading ..When I corrected this I got 1...As I said it puzzled me so maybe something is going on that I never recognised....
On Reflection I think I should not have done this testing on my small table but on the floor where I had no chance of losing control of the CCFL tube ...
Of Course I now wonder what inner damage I have done to one molex plug my inserting wires into it..
Hk


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## octaneman

HairyKiore said:


> Thats from Continuity right through the scale to 20M on my DMM??



Yes.


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## murihikukid

Heres the videos of my doing the resistance testing on the first CCFL assembly ......I used VLC player and GOM to play both on ...VLC there was no problem but GOM distorted the size till I used Full Screen Stretched...I did lower the resolution quite a bit to get the smaller file size...but they are quite clear...Actually this surely is the way to go ?? as you can see exactly what I am doing ..Hopefully the wires into the molex's are making contact ???????on the tube 2 video I repeated going from off to 20m as I wanted the continuity light to be seen when it flashed on and off..Hk


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## octaneman

On both videos the readings were ok when the meter flashed the readings for a brief second showing continuity ( 200k scale ) that the bulb is good. 



Nice job on the video recording.


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## murihikukid

I will get the second assembly done as soon as possible...Hk


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## murihikukid

OK...Maybe things are not as grim as I thought??? Here attached are Tubes three and four tests from the second assembly ...Hk


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## octaneman

Three and four show continuity.


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## murihikukid

OK..That I think means excellent news for me ......Do I now put everything back together again before I forget?? ..Hk


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## octaneman

Yup, the CCFL's are ok.


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## murihikukid

Hi...The monitor is now back together... where it was prior to the CCFL checks....I now wonder/presume I go ahead and put the new Mosfets on the original board...but first...during my reading etc on soldering I came across "Solder cleaner"...Is this another product or is it flux.....I want to get the area where the new mosfets are put in nice and clean beforehand..
If you recall I told you I did buy a package of "soldering stuff"...it included 4 soldering irons ...enough soldering flux to last several lifetimes and about 6 tins of soldering paste ...Unfortunately the labels are practicly unreadable so I haven't a clue exactly what it is but they may be very useful ...Hk


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## octaneman

You can proceed to install the mosfets just make sure you remove all the old solder and the solder points are clean, apply flux liberally to the contact points then you are ready to apply the iron. After you finish soldering the mosfets remove any excess flux using a cotton swab with isopropyl alcohol let it dry.


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## murihikukid

OK..It Seems I have made a terrible BASIC mistake ....and you have been probably scratching your head about what I have been going on about since we started on the Mosfets...What I failed to do was identify the etchings etc on the circuit board..I think I am right in saying that I got completely confused and what I thought were individual tracks are actually tracks of solder on the same copper backing so in fact they are all naturally connected...I have attached a photo..As I see it the Light Green is where the copper has been etched by the chemical they use...The Darker Green is the Copper...On the photo I have outlined in blue where I believe is the outer edge of the copper and any component mounted within the blue outline are connected...Could you please verify this for me and I will carefully inspect the Circuit board round the Mosfets and get things absolutely right ....then it should be Full Steam ahead....:dance:Hk


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## murihikukid

Just as an addon to my previous post....I wonder what the 3 wires do that go from one side of the mosfet to the other when it seems to me that they are attached to the same copper trace?Hk


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## octaneman

HairyKiore said:


> On the photo I have outlined in blue where I believe is the outer edge of the copper and any component mounted within the blue outline are connected...Could you please verify this for me and I will carefully inspect the Circuit board round the Mosfets and get things absolutely right ....then it should be Full Steam ahead....Hk



PCB's are layered so that the cost of manufacturing is cheaper, the blue outline is a trace and whatever is connected to it could be power or ground. 

The three wires are jumpers but without a schematic its difficult to know their purpose.


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## murihikukid

Hi..It seems to me that the solder has just run across the copper and showing up as in my photo ...My belief is that it does not matter ..that what I call solder tracks in that particular area apart from the gate and source pins are on the same piece of copper Trace on the circuit board ....
Thats how it is visibly to me and is backed up by my DMM readings....As I understand one has a circuit board that is etched and then solder tracks are applied then the board is sprayed with something ...I took the solder tracks as independant of each other whereas in many cases they are not...If I am explaining adequately where I am coming from ...It seems now that I have to go ahead and solder in the mosfets??? In Daylight ....hk


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## octaneman

HairyKiore said:


> Hi..It seems to me that the solder has just run across the copper and showing up as in my photo ...My belief is that it does not matter ..that what I call solder tracks in that particular area apart from the gate and source pins are on the same piece of copper Trace on the circuit board ....
> Thats how it is visibly to me and is backed up by my DMM readings....As I understand one has a circuit board that is etched and then solder tracks are applied then the board is sprayed with something ...I took the solder tracks as independant of each other whereas in many cases they are not...If I am explaining adequately where I am coming from ...It seems now that I have to go ahead and solder in the mosfets??? In Daylight ....hk




Yup, you did a good job preparing the board solder the mosfets and please post your results.


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## murihikukid

Hi Amazing what a 60W Soldering Iron does with a reasonably large tip ??One of the four bolts that were in the soldering package I bought..I now realise why wick would not work for me?? By the way I took a series of photos depicting each step in the Monitor assembly just in case it may help somebody down the line...Hk


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## murihikukid

OK...Its not raining so thanks to a pair of surgical pliers held in vice grips I was able to lightly pre-solder the 2 pins and back plate very easily ...Having previously freshly applied solder to the board I first soldered the Gate and source pins then applied some solder to the end top of the back plate and kept downward pressure with a piece of wood doweling...
Hope it passes inspection...Hk


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## octaneman

Fantastic job ! well done Hk.

Did you clean the area with isopropyl alcohol to rid of the excess flux ? if not please do so to rid the area of any residue and let it dry.


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## murihikukid

YES...I did clean it and then I took and posted the photo and later when I looked at it I could still see the excess flux so I used a small paint brush and gave it another clean so it looks much better now...I was extremely lucky as I had the first mosfet on and had tinned the second when a neighbour came over and started talking to me over the fence...the mosfet I had just tinned was on the towel and a small gust of wind must have lifted the towel enough to throw the mosfet off and on to the grass...I was extremely lucky I found it .....
SO
I wonder what is next ...Does the Transformer Inverter get re tested and then put back on the board // Hk


----------



## octaneman

HairyKiore said:


> I wonder what is next ...Does the Transformer Inverter get re tested and then put back on the board // Hk


Yes, once thats done you will check that the home made strand fuse is still intact and you will once again verify the voltages on the pins. Once they are there you will discharge the main capacitor first *before * you re-connect the logic board to the power board.


At this stage please be very careful not to accidently short out any of the pins. Take every precaution you think is necessary that it does not happen.


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## murihikukid

OK..Will go back to page 13 ...post 246 and try and video the 6 tests on that post...The one strand fuse is still intact but not the wire overhang as with shifting the board around it broke off.. Re shorting pins...I AM NOT going to do that again ..Hk


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## murihikukid

OK..I am late but attached you will find my video of 12 tests I have done ...If you require more please let me know ..Please Note the inverter was kept in the same position during all tests ..only the DMM leads were moved...I did try some Diagonal readings but got nothing...Hk


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## octaneman

Hk,


All your tests point to the inverter being completely dead.


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## murihikukid

Ok..So I wonder what options we have? As I understand you want the original board to be used so basicly that only leaves one a choice of removing the transformer inverter on my new imported board and putting it on the original..(after testing) ...Hk


----------



## octaneman

HairyKiore said:


> Ok..So I wonder what options we have? As I understand you want the original board to be used so basicly that only leaves one a choice of removing the transformer inverter on my new imported board and putting it on the original..(after testing) ...Hk




Yes , I want to use the original board because the signal process of the logic board. I don't want you taking any unnecessary risk in burning out the new mosfets so we are going to tread carefully. Everything is all set even with the inverter off you can still verify that the +5v stanby and +13v are present and accounted for, always remember to power down the board and discharge the main cap when you are done.


----------



## octaneman

Addendum : 

Hk, 

I cross checked the numbers on the inverter with a compatible replacement. The original number is 2874005300 which could be replaced with SPI 8TC00381, both numbers are complimentary to one another. 

8TC00381 Inverter transformer for Philips 190SW8 | eBay


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## octaneman

In the pic there is the before and after the mosfet installation I can see somewhat of a bridge connection on the trace. Please verify that there are no bridge connections.


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## murihikukid

OK..We have to get this sorted out...I think I know what you are referring too but with nothing marked I cannot be 100%....If you are referring to the back plate of the Mosfets ..I did try and get this verified several posts ago when I was trying to desolder and clean the Mosfet area.....
Now I could be wrong but have attached your photo and I have marked as I see what is soldered to the same copper trace ...there is the left mosfet and to me everything in yellow is on the same copper trace on the circuit board...the right mosfet in my opinion everything in red is on the same copper trace so if the back plate is bridged I cannot see how it matters as the solder tracks it is bridged too are all on the same copper trace and the solder just naturally ran across ...But I have got to be 100% sure here...Hk

PS..Thats why I commented earlier on the 3 wire string jumpers that go over the mosfets on the upper surface of the power board...they start and finish on the same copper trace? which to me means they do nothing..


----------



## murihikukid

Hi..Its a bright sunny day so I took the board outside with an eye magnifier and the sun was nearly reflecting off the copper trace ....The only component I am only 99% sure of is the mosfets as where they sit there is a very fine white line but I am sire its just printed on the surface and it just a reference to where the mosfets sit and of course I believe is on the same copper trace...I hope I am making sense here...Once I get this sorted out and check the voltages I will buy the inverter you have indicated..Hk


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## octaneman

I've marked the spots where you should focus on. We don't have a diagram so we have to be absolutely sure we keep the board original. 

There has to be a gap between the trace and mosfet ,clear up as much solder as possible from the trace until you see the green of the PCB.


----------



## murihikukid

Hi..What green of the PCB??? Right from the start I have not been able to see any green ..That was what I was looking for ...I have gone back to Page 13 ....post #260 (in my opinion there is no difference in the colour IE the darker green signifies the copper trace ...The lighter green signifies no copper trace..)..Just an extra point ...after I bought the old soldering equipment and used a 60W Antec iron...I have had no problems desoldering etc???
Now I move onto page 16 Posts #315 - 316...which show photos of the mosfets during removal ...I see dark green where the mosfets come from ..no light green ..(a white line) but no light green signifying an etched line ..I recall I checked all this with my DMM ....
I was concerned in particular about the left mosfet and that the backplate solder had bridged to the solder tracks (which do nothing???) 
I expressed this concern in page 18 post # 354 to #359.....Later on page 22 post # 427 I again addressed the question of where the mosfets backplate is soldered to the board and how all the cleaning etc I had done clearly revealed to me that the backplate and the solder tracks to the side and above and which I later marked in photos by colour were all on the same copper trace ..Yes there is a break at the bottom of where the mosfets are mounted and new traces where the gate and source are connected too but not at the sides or top ....
When I applied heat to the backplate overhang the solder just spread instantly due to the copper underneath that still had a minute film of solder on it that I could not remove....so it automaticly bridged ...

Do you want me to attach another photo with a line where etching has taken place ??Cause it is difficult to see as being so fine... 
I have just looked outside and there should be a patch of sun soon....I will take a closeup photo of the mosfets on the new imported board and this may clarify the etching a lot better..
Hk


----------



## murihikukid

Hi..I missed the sun...but have attached these...I might be able to get better later or tomorrow..Now one can clearly see the oblong thin line which I took as being painted on the board as a reference to where the mosfet should be mounted and not part of the etching process in the boards manufacturer ..but these are better photographs than ever before (from a new board) and hopefully will provide the answers to an experienced eye...Meanwhile I have sent the email hoping to get the specs required..Hk


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## octaneman

The oblong thin line is clearly visible of where the mosfets sits on the board. It leaves no doubt that there is a gap from the trace to the mosfet.


----------



## murihikukid

Hi..Well thats it ...to me that means the original board is stuffed ...What you are saying is that line is etched isolating the mosfet from the copper trace round it??which would mean that the backplate of the mosfet sits on the circuit board connected to nothing?? So I wonder why one puts ones DMM lead onto the backplate overhang (on the new board) and the other lead onto one of the solder tracks and one gets a continuity reading..Where is it getting its connection? .That thin oblong line in my opinion is printed just the same as the component part numbers (ie 0205 ) are printed onto the surface of the board?? Hk


----------



## murihikukid

My Inverter readings?? Things are real bad ..I cannot get audio on my captures except one and when I tried to make a complete file somehow Movie maker cut the clip in half when I dragged it into the timeline???... So hope I can resubmit my readings as individual video readings....So on each reading I go from Continuity across each setting to Off....Please look out for the Red Light on Continuity ....And now I realise that I forgot to turn the Webcam off on the Sixth reading???...??So will see if I can send this on another posting.Hk


----------



## murihikukid

Heres the last reading after I found out how to cut a WMV file...Hk


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## octaneman

Hk, 

Your latest test put the final nail in the inverter's coffin your inverter is completely dead.


----------



## murihikukid

In honesty I fully expected that ...Now I still want to get into my mind the situation re the Mosfets on the power board ...So I have attached a drawing..As I understand you believe that the oblong line (seen on photo postings) round where each mosfet sits... is an etched line IE it has no copper which means the area within the line is isolated.. Unless the board is multi layered? Hk


----------



## octaneman

HairyKiore said:


> In honesty I fully expected that ...Now I still want to get into my mind the situation re the Mosfets on the power board ...So I have attached a drawing..As I understand you believe that the oblong line (seen on photo postings) round where each mosfet sits... is an etched line IE it has no copper which means the area within the line is isolated.. Unless the board is multi layered? Hk
> .




Yes, the oblong line is a border line so when the mosfet is soldered onto its designated location the technician cannot solder the mosfet past those lines to interfere with other traces


----------



## murihikukid

ok..I can understand that but as I see it there is no rational behind it...the only traces it could interfere with are on the gate and source side...So I am missing something here ?? surely a train and its carriages are on the same track... However I am doing my best to find a schematic..Hk


----------



## murihikukid

Hi Just wondered if these are Mosfets?? Hk


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## octaneman

Yes they are.


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## murihikukid

Hi..I have done these over and over and they are not getting better that what you see ...So I wait for your comment...Hk


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## murihikukid

I have just powered up the latest board and got 14.27V and 5.06V at the pins...
I wonder if it would hurt if I tried it? Hk


----------



## murihikukid

Heres the Hakko 60W I am using instead of the soldering station plus I have the Weller 40W but have not used it yet....I went back and retested the other DAC19M009 I got weeks ago at the pins and got 14.30V and 5.04V ...I cannot recall if I actually put this on the monitor or not ..I must have but the unit never powered up...Next Time I will try and set up the webcam and you can see what is going on..I will also take some photos of the frame power assembly (if one could call it that ) that somehow are supposed to push against the 5 switches on the OSD and put it on with this post...hk



Do the molex connectors go to the speakers ?


----------



## octaneman

HairyKiore said:


> I have just powered up the latest board and got 14.27V and 5.06V at the pins...
> I wonder if it would hurt if I tried it? Hk




I'd definitely would give it a go.


----------



## octaneman

HairyKiore said:


> Heres the Hakko 60W I am using instead of the soldering station plus I have the Weller 40W but have not used it yet....I went back and retested the other DAC19M009 I got weeks ago at the pins and got 14.30V and 5.04V ...I cannot recall if I actually put this on the monitor or not ..I must have but the unit never powered up...Next Time I will try and set up the webcam and you can see what is going on..I will also take some photos of the frame power assembly (if one could call it that ) that somehow are supposed to push against the 5 switches on the OSD and put it on with this post...hk




Do the molex connectors go to the speakers ?


----------



## octaneman

HairyKiore said:


> Hi..I have done these over and over and they are not getting better that what you see ...So I wait for your comment...Hk




Do the best you can and cross your fingers.


----------



## murihikukid

octaneman said:


> Do the molex connectors go to the speakers ?


Yes..They do..Hk


----------



## murihikukid

octaneman said:


> Do the best you can and cross your fingers.


Yes ..but the more cleaning I do the more the solder is spreading ..I presume I am basicly cleaning the copper trace and it does not look good ..I used wick then isopryl alcohol to clean ...Just an observation ...I wonder if the solder flux is a problem doing a job like this...??? I will order the inverter you recommended ..Hk


----------



## murihikukid

OK..?????Powered on with latest board....I have a blue light on the OSD board ...because the plastic rim is off the screen I do not have the light enhancer on it for the blue LED light to shine through so I do not know if its soft power or Power on..Hopefully thats an adequate explanation but I have worked the power on /off switch manually several times with my finger tip and it is the same old story ...It does nothing ..Turn the power off via the power guard no light..Turn the power on via the power guard and we have the minute blue light on the OSD board...and no amount of pushing the on/off switch changes this...so there is something going on here that we are missing... We do not have the normal power on procedure IE on,off, standby etc..Hk


----------



## octaneman

When you powerd up the board did you notice the back lights come on ? 


What about the OSD board ? Did you press any other buttons besides the power on/off to see in case a dialog box poped up ?


----------



## murihikukid

Hi ...Here it is on video and with Audio so you can hear me switching On and Off via the buttons on my Power Guard ..I got lucky and after a no go start when all I kept getting was the blue soft power it suddenly powered up but the video tells it all...The 4 zip attachments show part A,B,C and D of a 6 minute WMV file ..So you could unzip and play them in order or unzip and join them together in Movie Maker as one video... 
I just wonder if you get some answers here but take no notice of my words before it powered up as I did nothing..Except switch it back on via the powerguard switch...and there it was ..powered on..the intermitant flashing of the screen surprised me and its a good job I actually looked or else I would not have noticed it...Note..I did push the power on but it did nothing.. Hk


----------



## octaneman

This is the board from Hong Kong right ? 

On video C the screen flashing is due to a bad filter capacitor on the power supply side. One of the main filters is leaking just enough to contaminate the D/C power stream.


----------



## murihikukid

OK..Thanks Hk


----------



## murihikukid

Heres the video of the flash ...its 14-15 second into the video ...Hk


----------



## murihikukid

Hi..I am removing the main board for photos ....However I have a small problem with the ribbon cable feeding the OSD board...I do not know how it is released from the main board...The two ribbon cables feeding the LCD Screen circuit board are no problem but at this stage I just do not see how the cable release to the OSD board works...

Now I have attached a photo of the cable in question plus a good quality photo of the main board that I had on file...Once I know how to get the main board off I will be taking a photo of the underside for posting.. Hk


----------



## octaneman

HairyKiore said:


> Hi..I am removing the main board for photos ....However I have a small problem with the ribbon cable feeding the OSD board...I do not know how it is released from the main board...The two ribbon cables feeding the LCD Screen circuit board are no problem but at this stage I just do not see how the cable release to the OSD board works...
> 
> Now I have attached a photo of the cable in question plus a good quality photo of the main board that I had on file...Once I know how to get the main board off I will be taking a photo of the underside for posting.. Hk




I've done a pre-lim of the logic board and I've marked certain components that contribute the flashing screen. The components are the voltage regulator which you will need the datasheet to test and the 2 EEPROMS chips ( Electrical Erasable Programmable Read Only Memmory). There is a reset on the EEPROMs that you can do on your monitor that will set it to its default settings just in case its been corrupted. 

To reset the EEPROMS press and hold the :[▼] +[▲] with the power on/off switch. The screen and LED indicator should cycle from stand-by mode to power on, If there is no response from the EEPROMS them its a certainty that the logic board has a serious problem.


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## murihikukid

The voltage regulator has ZCPk on the top ...As far as taking off the board ..I basicly spent all day yesterday trying to find out how the ribbon cable to the OSD board unlatches and I still do not know??Hk


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## murihikukid

OK Heres the photos ...The ribbon actually had an adhesive pad which held it in place on the metal frame so when it just peeled off there was no necessity to unlock the ribbon cable and I just left the ODS connected to the Logic board ..removed both together and took the following photos which I have zipped up...and attached ...
You will see there is nothing under the Logic Board as far as any components are concerned....
I will now put the Logic and power board back on and await your instructions....Hk


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## murihikukid

OK..You must realise I am not the brightest but re the flashing monitor ....Are the LCD ..the Lights etc controled by the circuit board attached to the screen which is attached by two ribbon cables to the main/Logic board ??? But what if the cables are disconnected from the Logic board ?? Because in the tests we did my cables are disconnected.. ??? Hk


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## octaneman

The LCD lights are controlled by the logic board if a single ribbon is disconnected or not seating properly the flashing of the screen would be the first sign. The ribbon cables have to be connected properly to the logic/OSD boards for the power up tests to be conclusive or else were just spinning our wheels.


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## murihikukid

Yes...How did I miss or not realise that ..??I will have to do the power on tests again with everything properly connected... Hk


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## murihikukid

As a follow up ..I set everything up to video and took a 12 minute video ...I got a few flashes but could not get the unit into full power mode so I really do not think its worthwhile posting the video ..Hopefully tomorrow I may have more parts and we can really get into this and establish just where our problem is coming from...Hk


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## murihikukid

Probably does not mean much ..But I have just resumed doing some power on/off tests and what is happening I get soft power on while what I presume is the orange standby flashes..This was happening each time I power on ?? I just tryed again and back to the same softpower blue and a very weak Standby Led..Hk


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## murihikukid

Nothing has arrived  this morning ?? So I wonder if you could repeat the tests to do on the Voltage regulator on the logic board...I recall the uncertainty about the pins but the left pin must be Ground....It would just give me something to do and maybe we might just catch onto the problem ..Hk


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## octaneman

HairyKiore said:


> Nothing has arrived this morning ?? So I wonder if you could repeat the tests to do on the Voltage regulator on the logic board...I recall the uncertainty about the pins but the left pin must be Ground....It would just give me something to do and maybe we might just catch onto the problem ..Hk



Did you solder the original inverter on to the power board ?


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## murihikukid

octaneman said:


> Did you solder the original inverter on to the power board ?


Yes It was me.....Now I have just now finished my document on the OSD board ...I have yet to do the ribbon cable .....I hope you understand the file ...Its in photos .. I will actually put the ribbon cable back in the OSD board and remove it from the logic board ..Then I can use the 15 pins on the OSD board as one end and the ribbon cable end removed from the logic board as the other ......Hk


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## murihikukid

OK..Done the Ribbon Cable and checks out OK...I wonder if I can check out the voltage regulator ?? If I recall right..the DMM supplys the power... 
Just checked the left pin with continuity ...EG Black lead to Ground via the ground on the DVI socket and red to left pin on the regulator ...No Continuity so decided to stop?? Hk


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## octaneman

HairyKiore said:


> Yes It was me.....Now I have just now finished my document on the OSD board ...I have yet to do the ribbon cable .....I hope you understand the file ...Its in photos .. I will actually put the ribbon cable back in the OSD board and remove it from the logic board ..Then I can use the 15 pins on the OSD board as one end and the ribbon cable end removed from the logic board as the other ......Hk



When you were doing the continuity test on the pins were you pressing the switches to the on position or was the meter giving you continuity without pressing down on any of the switches ?


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## octaneman

HairyKiore said:


> OK..Done the Ribbon Cable and checks out OK...I wonder if I can check out the voltage regulator ?? If I recall right..the DMM supplys the power...
> Just checked the left pin with continuity ...EG Black lead to Ground via the ground on the DVI socket and red to left pin on the regulator ...No Continuity so decided to stop?? Hk



No continuity ?! , Then there could be a broken trace to ground. You have to double check that with all the pins on the regulator.


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## murihikukid

octaneman said:


> When you were doing the continuity test on the pins were you pressing the switches to the on position or was the meter giving you continuity without pressing down on any of the switches ?


Hi..I just Attached to a pin and tested for a continuity ..I never pressed any switches ...Hk


We have to know if there is continuity when the switch is pressed.


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## murihikukid

octaneman said:


> No continuity ?! , Then there could be a broken trace to ground. You have to double check that with all the pins on the regulator.


OK..There was no continuity but there was a reading ....but I stopped in case I do any damage ...I need more instruction here on what is required ...I thought if the left pin was ground as the data sheets seem to indicate ..I should get continuity audio as long as I had my leads from the left pin to another ground point... The other 2 pins are voltage I think....Hk


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## octaneman

HairyKiore said:


> Hi..I just Attached to a pin and tested for a continuity ..I never pressed any switches ...Hk
> .



We have to know if there is continuity to the pins when the switch is pressed.


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## octaneman

HairyKiore said:


> OK..There was no continuity but there was a reading ....but I stopped in case I do any damage ...I need more instruction here on what is required ...I thought if the left pin was ground as the data sheets seem to indicate ..I should get continuity audio as long as I had my leads from the left pin to another ground point... The other 2 pins are voltage I think....Hk




The only way to know is to power the board and take voltage readings off the the 2 regulator pins.


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## murihikukid

octaneman said:


> We have to know if there is continuity to the pins when the switch is pressed.


Hi..hope this is the answer you are looking for.........When the Switch is pressed down I get continuity on all of its four pins to its relative cable pin..... all 5 switches have been tested with identical results ..Hk


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## murihikukid

Mmmm...Don't know about these readings.......Hk.


PS..RE The previous post .I realise I may have not explained correctly on the attachment so I will have another try......The top two pins on each Switch have continuity with their relative Cable pin ...When the button is pushed all four pins on each Switch have continuity with their relative Cable pin


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## octaneman

HairyKiore said:


> Hi..hope this is the answer you are looking for.........When the Switch is pressed down I get continuity on all of its four pins to its relative cable pin..... all 5 switches have been tested with identical results ..Hk



Ok thats what is supposed to be.


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## octaneman

HairyKiore said:


> Mmmm...Don't know about these readings.......Hk.






The voltages are low and i'm speculating that the board has not reached its full power because its not switching on.


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## murihikukid

Ok ...Is there any test one can do to determine why the main board is not switching on...Hk


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## octaneman

HairyKiore said:


> Ok ...Is there any test one can do to determine why the main board is not switching on...Hk


The main board is switching its the logic board thats not switching. To test for that you need an oscilloscope to look at all test points on the logic board.


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## murihikukid

OK..No main board today but one inverter? They sure made the shipping cost high for such a small item and when compering with charges for the boards...but we now have a new spare inverter.... the second VX2235wm-5 has been shipped so will arrive by the weekend so we should get at least one working and hopefully two pretty soon....One presumes that even if one was able to find the component on a main board that was faulty .. it would make no difference as a complete working board still would have to be found...
Thanks Hk


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## murihikukid

OK..We are back in business??? I apologise for the video quality but I wanted to get it in two files and spent 2 hours trying to sort it out and found out that there is a significant difference between Zip and Rar Compression....so attached is the exact footage I got when the monitor was fired up with a new logic/main board (although it is split into 2 parts ).......
I think the cat says it all at the start ??? 

The significant difference is in the brightness of the Blue and Orange LED's ....Is the Blue LED I get when power is applied "Soft Power" (I presume it is ) and it is followed by standby ...At the start although it looks like I am actually pushing the switch when it changes from Blue to Orange ..I never did push it..it changed from Blue to Orange automaticly .....I thought that next there should be Power On when I pushed the switch??....but you will know that better than me....If there should be ??? its not there....so thats a real disappointment ......There is absolutely no hint of a flash etc from the CCFL tubes..
I wonder if it needs a signal from a connected PC to fire it up ...or should I try another power board??? perhaps the latest one received ....Unfortunately we have only one logic board apart from the original which I am pretty sure has been established is faulty.....
We have checked the OSD board so basicly thats it ..its got to be the power or logic board unless its because the monitor needs a signal from the PC to complete the fire up process....
But as usual I eagerly await your comments as you may see everything completely different than myself...Hk


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## murihikukid

Here is New Logic board with Latest Power Board..at least the screen is showing something? hk


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## octaneman

HairyKiore said:


> Here is New Logic board with Latest Power Board..at least the screen is showing something? hk




Hook up the serial cable and fire up the monitor and pc, The standby is on so it will need a signal from the pc to fully power on.


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## murihikukid

Hi hope you can understand these readings..Hk


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## murihikukid

Hi..I decided to try and fire up the Second Viewsonic and see what happens..but it will not fire up ..I have blue led and standby but thats it...so I decided to have a quick look inside....and if possible do some checks..
Now this interested me...although it probably means nothing but I thought I should check with you...
Its the wires that go from the inverter to the CCFL tubes.....On the original monitor the wires are as on the photo attached...on the new Viewsonic the black and blue wires feed the top two CCFL tubes and the pink and white wires feed the bottom two.....Hk.

PS..Its a double inverter power board and the Capacitors are clearly bulging at the top...


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## murihikukid

Hi..I wonder if I should put the "open for business" notice at the gate?? Maybe not...In the #2 viewsonic I just put another power board in and powered up.....and away it went....I did not think it worthwhile to replace the capacitors with two double inverter boards available ...
Now maybe we can use this setup to work out a procedure for a guide for the original viewsonic...??
I do have a couple of questions ...One is relating to what looks like a food stain running down the screen in the lower right of the monitor ..I think its visible in the video .....I do not think its on the outside unless I am not cleaning it properly ...then there is the video ...Is that normal for a high priced webcam to go in and out of focus like it does considering its completely untouched ..I do not think it did that earlier so maybe I should take it back to the shop..??
A success certainly makes a difference ..Hk


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## octaneman

Your web cam should not zoom in an out of focus at random I'd take it back to the shop if I were you. 

You could replace the capacitors and have it as a spare or auction it off as a functioning power board and get a few bucks for it.


The monitor has what appears to be an indentation from what I saw in the video. An object must have been rubbed hard on the surface of the screen, it doesnt appear to have any effect on the pixels so by my perspective the screen is ok. The monitor works I'd leave it the way it is.


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## octaneman

HairyKiore said:


> Hi hope you can understand these readings..Hk



Yes I can read them. 

The Hong Kong inverter readings make more sense. Low resistance on primary high resistance on secondary.


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## murihikukid

I am up and running having tea at nearly 5 am..??Well ..I could put the new inverter on the original board and then put it in the original monitor and see what happens.....what do you think?
hk


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## octaneman

HairyKiore said:


> I am up and running having tea at nearly 5 am..??Well ..I could put the new inverter on the original board and then put it in the original monitor and see what happens.....what do you think?
> hk




Would be a good idea, you didn't go through all this to let it rot on some shelf.


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## murihikukid

OK..Just powered up and no luck...still got a double screen so all I can think of is to put in the original powerboard with the new inverter and check out the ribbon-cable to the OSD...Its a pity I have not got a spare OSD??Hk..


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## murihikukid

OK..Powered on ..Blue Light on but no Standby light and the monitor is dead so the original Powerboard still has a problem??? Maybe??...So I will just keep on trying Power Boards??? Hk


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## murihikukid

Ok..Tryed the new Ebay Power board ...and its powered up but again it has a split screen ..I have just emailed a snap shot to the agent...so maybe he will offer advice ..Cheers Ron


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## murihikukid

octaneman said:


> Would be a good idea, you didn't go through all this to let it rot on some shelf.


Well thats where it might end up ...clearly there is something we/I have missed on this board ....I will recheck the fuses etc and the pin voltages..and try another board ??

BUT back to now...what if I take the OSD board off the New VX2235wm and put it on this nasty....then see if it fires up into a full screen picture??if it does its the OSD board or the ribbon....HK 


Hk


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## murihikukid

OK..Its not the OSD or Ribbon Cable as I swapped them and I am still getting the split screen..Hk...


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## murihikukid

I wonder if you could offer any suggestion on how to hold the OSD board in place ...I see many of the VX2235wm's for sale all have power up problems but is it actually the power board?... I have found that the OSD board can easily move out of position when the Power On is pushed and the switches then lose contact and will not work....Ideally I feel that some tape should be used to secure the board in place but what type of tape would be best .....Hk


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## octaneman

There are adheasives available for PCB's, but you can use contact cement on the edges of the OSD to keep it in place as long as it doesn't affect the traces it'll still work.


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## murihikukid

Hi..I thought this might help...I have done the same tests on the original board and the China board which is a goer....I have attached a jpg with the cap numbers I have used plus a jpg of my results ....Concerning the 13v results on Cap 5 and 6 ...on the original board they charged up to 1.843....on the China board they charged up to 2. then immediately reverted to 1. so there was a small difference there ...
The difference that does shine out is the Cap 1......I hope this may help ...Hk


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## murihikukid

Here are the tests >2nd pin ground to the positive of the capacitors....Caps 5 and 6 on the China boad charge up to 2 and instantly revert to 1 on the DMM..
Again on the original board Cap 1 shows out...Hk


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## murihikukid

Hi...I will try another identical cap for #1 from another board so after getting the caps mixed up I have to try both...I do not learn?? ..First both gave me identical readings which left me with no alternative but to try each one on the board and power up....So with the first one ..it powers on but no picture so I will now replace it with the other cap ...Oh Dear???? I should have checked the pin voltages ??? I will do that now..14.35 and 5.04 ....Its later and I have now put the 2nd cap in and as I expected the result is the same ...power on but no picture but I have the voltages at the pins.....
I will now recheck what all my minimal knowledge is telling me....The new Inverter that I bought from China.......So I will take the readings and also compare them with the same readings from the new board that I know works...I should have these results in an hour or two ...Its got to be the inverter???????

Question?? Can I risk any damage if after taking readings etc ..I actually removed the inverter from my new board and put it on the original board ...Surely if it didn't fire up then it would require a complete rethink....but with the correct pin voltages and what I have learnt over this exercise I am betting it will fire up...Hk


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## murihikukid

OK...I have the results ..the Primary readings check out..The secondary readings do not...On the China board which I put in the unit to make sure it fired up..No Problem We have .548 on a 2K setting or .478 on continuity....
On the Original Board with the Phillips inverter we have .972 on a 2K settings and .739 on continuity....

SO I am going to gamble here but do not think it will be a problem ..I will remove the China Boards Inverter and put it on the original board....If the Original board fires up we then know that the Phillips Inverter is not compitable ..Cheers Hk


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## murihikukid

Hi..Bad news...and I am extremely disappointed ...My theory has not worked out...The inverter from the China board is now on the original board and its back in the unit hooked up to the PC...its got 14.35V and 5.04 V at the pins as it should have....There is absolutely nothing except a Blue Power LED thats it....So we are missing something here on the Power Board ..I presume there is a component here that is not working on the inverter side but what is it?? We have basicly checked everything but I am like a dog with a bone and will not be happy till the problem is identified...Cheers


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## murihikukid

A Fuse should give continuity ..Right?? why do I think this board is making me look a fool ..F200 has not got continuity ..the China board F200 has continuity so I will now try and put a one strand wire across F200.... and try it ...Hk


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## murihikukid

Things are turning to custard here...I put a single strand wire across F200..put the board back in and nothing not even a blue power on light ..Removed board and tested voltages at the pins (which I should have done first) and the 14.35v at the pins is gone ...There was a big buildup of V at the main capacitor???
So I tried doing some checks by probing with the DMM on Continuity round where I had soldered IE Capacitor 1 and F200...and I got continuity across the Pos/Neg of Capacitor 1 (see post 513 photo) ..Cross referenced to the China board and no continuity on it so clearly something has happened to the original board and clearly I am out of my depth ...Surely my soldering has not shorted anything out but I will wait til daylight so as I can really inspect the board...I wonder if putting a single strand wire across F200 was wrong ....?? Hk


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## murihikukid

Hi..I could not do power tests of the Transformer simply cause when I put power on I can smell something heating up ..I did try to do a test immediately between two pins with power on but the DMM was flucuating badly and of course I could smell that something was heating up so I powered off ...I am going to remove the strand wire ...simply because I never had this heating prior to putting it on ...Hk


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## murihikukid

OK. I have removed the capacitor and the strand wire..so I make a clean start with hopefully no sign of heat ...I have basicly mastered the copper wick now for desoldering and have attached a photo of F200 and the Capacitor place on the board..I do not see any problem ..it looks clean to me ..So I will power up again and see what happens.. Hk


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## murihikukid

With Power On I cannot get any reading on the transformer IE they are all 0.00 apart from a infinity reading between two pins...I will now check the power diode..Hk


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## murihikukid

OK..I need directions how to test the Power IC on the heat sink (circled) do I remove it /desolder it etc ....The other two diodes circled I can get directions from page 1 and 2 ..I presume with no power at the transformer something has blown in this area..Thanks Hk


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## octaneman

On the power mosfet STP6NK60Z which is on the heat sink there is a duel diode safety feature built in it for overvoltage so it tests different from conventional Mosfets. Look at the diagram for the pin-outs.

Testing it from gate to source your meter should get a reading the same applies when you reverse your leads. 

From gate to drain; Set the meter on 2k scale and you're going to test from gate to drain the readings should be infinity, you should get the same readings when you reverse your leads.


From drain to source; set the meter on continuity the meter should give very low resistance readings. 

If you get any other readings the mosfet needs replacing.


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## murihikukid

Hi ..I got another good zap yesterday so will really have to be more careful ..again when I then shorted the Cap there was a significant flash from the lightbulb as though the main cap had been really charged up....removing the capacitor and the one strand wire seems to have stopped the heat that I am sure I smelt coming from the board so I must have shorted it with the single strand fuse wire and no doubt damaged a component in the Pre-Transformer part of the Power Board...
The really stupid part of all this is that now I have continuity at F200 ...I can only presume that my DMM leads were not making proper contact prior to my soldering the strand across it...I think these boards may have a spray on them that sometimes resists getting a contact and this is what happened when I tryed originally several times ..to get a reading on F200...
So later today I will get into it and try and find out if I can diagnose the problem ... Thanks..Hk


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## murihikukid

I forgot to ask..On the power Mosfet STP6NK60Z...does it have to be desoldered to get the readings? Thanks


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## octaneman

HairyKiore said:


> I forgot to ask..On the power Mosfet STP6NK60Z...does it have to be desoldered to get the readings? Thanks



It doesn't have to be removed off the heat sink but to get accurate readings its best to desolder the pins .


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## murihikukid

Hi..I am going to try and get the tests up ..starting with the Power Mosfet...I had to do some serious downgrading of the clip so as I could put it up on the forum ...theres no reading til the drain and the source where I get .538 on continuity with the negative lead on the drain and positive lead to the source...change the leads around IE Positive on the drain and negative lead to the source I get infinity 1....Will be back soon with the diodes..Hk


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## murihikukid

Hi..Heres a video of my testing of Diode Number One....I have the DMM set to 20M resistance...Diode Number Two will be up soon.. Hk


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## murihikukid

Heres Diode Number two being tested also on a 20M setting ... Hk


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## octaneman

HairyKiore said:


> Hi..Heres a video of my testing of Diode Number One....I have the DMM set to 20M resistance...Diode Number Two will be up soon.. Hk




Diode one is ok .


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## octaneman

HairyKiore said:


> Heres Diode Number two being tested also on a 20M setting ... Hk



Diode number two is also ok.


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