# LCD Monitor



## g3n0cide (May 18, 2007)

I recently received a LG 192WS-SN 19" LCD Monitor. I turned it on, and it shows the desktop for 2 seconds and goes black. So after findout its either the power supplr OR the backlights, I opend the sucker up. I totally unassembled the monitor, took out the back lights, tested them, put the entire thing back together. And now when I turn it on, I get colored vertical lines on the ends of the monitor and my desktop is all blurred and distorted. Im not sure how to fix this, I have tried reconnecting everything. Does the order of the layers that make up the monitor have any influence on colored lines.


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## tigertunes (Feb 6, 2008)

Hi there i have recently disassembled quite a few flat screen monitors and have actually found a fix to the problem you were originally having, which is actually bad capacitors on the main borad , you can usually identify these visually as they will be either swollen from the sides, bottom or top, bare in mind the top side of a capacitor should be nice and flat, you will find that this is were the swelling usually begins to occur and changing these will resolve your issue, it is also a common problem with most pc,s that will shut themselves down but appear to boot and load up fine.
As to your newer issue i personally think that you may have assembled it incorrectly and certainly sounds like a connection problem, the wires inside a monitor i find tend to degrade under the immense heat that occurs in the normal usage of these things so if you have already checked all connectors are properly installed then run a continuity test on the wires that you can access in case a break has occured inside one of them, i am not sure about thelayers in the screen but i do know unless you have a cracked lcd and need to remove the layers then you should not really need to remove them but i have no clue if the order they sit in is specific although i think certain layers are prbably but at the same time i would think that this would not cause your coloured lines
Hope this bit of insight helps a little and let me know how you get on 
Regards
Tigertunes


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## g3n0cide (May 18, 2007)

Well the only real connection that I could check would be from, the screen to the VGA board, via a ribbon cable. I have checked this many times. Do you think maybe I could of shocked either the main board or the vga board. There are no cracks in the LCD screen


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## forlon4 (Feb 6, 2009)

Hey I have had the same problem replaced 1 Capacitor off the power board , power to digital signal board is up and backlights are up as well however now I have the problem of a full screen of vertical colored lines. I don't see any cracks or chips in LCD screen resoldered everthing all my drivers are up to date for this viewsonic optiquest Q191WB , resolution is set at 1440 x 900 as this is native resolution still have this happening is the LCD broken and I don't see it ? How about some help someone?


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## forlon4 (Feb 6, 2009)

oh ( it sounds like we did exactly the same thing ) I was also wondering if the order of the layers were of significance but after reopening the screen area up I found that there was no possible way to change the order due to the special cut aways (keyway ) to the screens , reinstalled made no differance what so ever. Help!


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## DonaldG (Aug 23, 2007)

Hi Folks

I have never opened up an LCD so no absolutely nothing on how they work.

However, when replacing capacitors, it is essential that replace them with the same capacitive value, You can deviate from the voltage value as long as the replacement has the same or higher voltage value.

It depends on where abouts in the circuitry the capacitor is to determine the criticality of it's capacitive value. If it is in use to stabilise or set a frequency of something, the the capacitive value is critical.

If the capacitor is used as a decoupler, the value is not so critical as long as it is near the original value.

If the capacitor is an electrolytic or tantalum type then it must be put in the correct way round. You will see either a + of - symbol to determine polarity.

There is more to it but the above should cover most aspects of replacing a capacitor.

Hope that helps and sorry if I am preaching to electronics engineers :grin:


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