# Burning smell and loud CPU fan after installing new video card, psu



## ggonzalez777 (Oct 6, 2009)

Hello forum,

This is a pretty interesting story. I wanted a new video card so I could take advantage of the new Nvidia/Windows 7 GPU/CPU processing that was announced a few weeks ago. Plus I really like using animated wallpapers(dreamscapes rock!!!). So I went out and bought a Nvidia 9400GT 1GB video card. Didn't want anything crazy since I don't really play games or such. I installed it and it works ok. Then I started to get a weird burning odor coming from the computer. I thought it was the video card but the card is cool as fall. So I checked the power supply and it reeked when i smelt it. I figured it was getting overworked so I checked Nvidia web page and saw that the card required a 300W min PSU. So I went ahead and bought a 500W Coolmax PSU. I again installed and it works well but, don don DOOOOOON!!!!, the smell from hell returned. I couldn't believe it, the smell is disorienting. Not only that but now my CPU fan ramps up the longer I use my computer. I used Speedfan to check my rpms and it goes up to 4000!! It's so loud and my temps read 55-65C sometimes 70. I have a P4 Cedar Mills at 3.2GHz and I've researched that the CPU is known for being a hot potato and that explains the ginormous heat sink / tower. But before installing the PSU it wouldn't be that loud except on startup. Now I'm going out to buy a quieter fan. I just wonder if maybe I have another problem unbeknown to me. The smell is bad and now i smell it every time I'm near any computer. I'm tempted to plug a glade apple cinnamon or something to mask the smell but I don't want to cover a dead pig in silk if you know what I mean. Somebody help me please? My last option is to go to a computer repair center to analyze the issue but like the forum's motto reads: "We are offering free computer tech support for everyone." I'm hoping someone can help me troubleshoot the problem. I'm a electronics technician with many years of experience so please be as explicit as possible. Thank you in advance.


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## speedster123 (Oct 18, 2006)

> bought a 500W Coolmax PSU


this is a low quality supply-
http://www.techsupportforum.com/f210/power-supply-information-and-selection-192217.html


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## ggonzalez777 (Oct 6, 2009)

Dang it. So you recommend changing it? Even with the increase in wattage? How would the sped up CPU fan be explained?


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## ggonzalez777 (Oct 6, 2009)

One other question. How long *sniff sniff* does my PSU have before it causes damage? I wouldn't be able to get another PSU for at least 3 months. Especially since I plan on getting the Coolermaster Real Power Pro 650 watt.


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## greenbrucelee (Apr 24, 2007)

Your psu could already be doing damage.

When a PSU starts to fail especially cheap bad brand models it will eventually start to cause intermittent errors like shutdowns, ram damage etc etc.

The can also cause abnormal voltages which create heat which is probably why your cpu fan is working really hard.

Can you get into the bios? If so post your temperatures and voltages on here


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## ggonzalez777 (Oct 6, 2009)

In bios I read a 32-34C temp measurement, didn't see a voltage reading. I'll have to download speedfan again when I get home. I do remember seeing a 12.74V on the 12V rail when I first started the program. and a -16V on the -12V rail. Well the CPU fan hasn't been loud as of late even with me running high cpu intensive programs. But the smell continues. I worry that I'm going to start spending a lot of money on a problem that is going to continue even if I replace my PSU with a another one. But I will try to get it ASAP.


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## FreoHeaveho (Aug 22, 2006)

I know this forum doesn't recommend low quality units, and I agree, however I am concerned that the PSU isn't the problem here. If the PSU has once *already *been changed and it continues to make this smell, then it would be very unlikely to be the PSU as a problem. Secondly, that PSU has around 36A on the 12V rail (EPS) so it has plenty of amperage for a 9400 and that system in all probablility.

My advice is, before you get a new PSU (AGAIN), is to do a complete rebuild, checking for motherboard standoffs, dust, correct thermal paste application and wire insulation damage. I would then check the 12V rail *under load *with a multimeter to check it is within specs (give that you are an electronics tech).

Voltage Rail Tolerance
+5VDC ± 5 %
-5VDC (if used) ± 10 %
+12VDC ± 5 %
-12VDC ± 10 %
+3.3VDC ± 5 %
+5VSB ± 5 %

Then and only then would i recommend ANOTHER PSU.


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## HawMan (May 12, 2006)

I would take the heatsink off the CPU and redo the thermal paste with arctic silver 5.


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## FreoHeaveho (Aug 22, 2006)

HawMan said:


> I would take the heatsink off the CPU and redo the thermal paste with arctic silver 5.


i too think this will be the issue.


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## greenbrucelee (Apr 24, 2007)

The reason why I have said it could be the PSU is because I have had this issue myself. But it's best to cover all bases.

clean all dust away from inside the case and from fans.
Take the heatsink off and clean the heatsink base with 90% isopropyl alcohol
Clean the CPU with 90% isopropyl alcohol (or you can use arti clean from both)
Redo the paste on the cpu and attach the heatsink and make sure it's properly attached.

Can you describe this smell?

When a PSU starts to burn out the only way I can describe it as burnt fish n chips soaked in vinegar and slightly rubbery.


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## ggonzalez777 (Oct 6, 2009)

And who says there's no compassion in the world!!!!! Thanks guys I will get right on it. If it helps, I have added a few things like another DVD-ROM drive and 2 DD2 553MHz 1GB RAM sticks. I checked on a PC wattage calculator and adding up all my components and the 30% it still only adds up to 310W. You know, come to think of it, I recall seeing the thermal paste very dried up on the CPU. That could be a problem. Question, what's the -12V rail for? I can't think of a reason for a reverse voltage rail unless it was being used as a reference voltage. Also, I sorta, kinda, in a way bumped some caps when I removed the metal strip closing the PCI-E expansion bay. I checked the components and they seemed ok. These caps were near a BGA chip in front of the PCI-E16x slot. I'll have to take it out and analyze it under a microscope. My motherboard is a 945GCT-HM if anyone can find out what that chip is that would be great. I looked under the supplier's site but they didn't identify and I also went under HP's site for the motherboard specs and there is some lettering in the picture provided but its unreadable.


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## greenbrucelee (Apr 24, 2007)

sounds like you mean capacitors. If any are bent, look like they are collapsing on themselves or are leaking then your motherboard is damaged.


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## ggonzalez777 (Oct 6, 2009)

The smell is not poignant, nor does it smell plasticky. It's more like metal heating up, but yet my PSU is cool to the touch. I managed the PSU cables so there is no obstruction in front the PSU fan. I recently cleaned all the fans in my PC.


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## ggonzalez777 (Oct 6, 2009)

Yea, I'm just used to tech talk I did mean capacitors. Well, these capacitors are SMT not electrolytic. The worst I can think that could happen is that the BGA would not get powered, not start to pull more current unless the other capacitors are overstressed and begin to compensate. Pulling more current would definitely make me think the PSU is getting overworked. Like I said I'll have to look at them more closely to determine the damage. If worse comes to worse, i could remove the mobo and take it to my tech bench and retouch the solder connections. I love troubleshooting!!!


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## greenbrucelee (Apr 24, 2007)

I would do that but get a torch and shine on on the mobo, see if they are any burn marks or grey staining.


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## ggonzalez777 (Oct 6, 2009)

None that I noticed. I still don't know what that chip functions as, but I'll continue looking. Definitely have to check my voltage rails. Maybe even determine my PC's overall wattage usage with some simple math.


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## greenbrucelee (Apr 24, 2007)

Before I replaced my smelly psu it was also cool to the touch.

I worked it out that it was the psu because I powerd down the system with the side of the case and put my nose right above the psu fan and that was were the smell was coming from.

Then I tested it with a multimeter and came to the conclusion that was about to die.


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## ggonzalez777 (Oct 6, 2009)

What did you measure? I suspect the 3.3V or the 5V rail since that's what most BGA chips operate on.


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## greenbrucelee (Apr 24, 2007)

Yes, you put the probes in the ATX connection on the mobo


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## ggonzalez777 (Oct 6, 2009)

Ok I'm home now and installed Speedfan and these are my voltages and temps:

Vcore1: 1.15V
Vocre2: 1.49V
+3.3V: 3.34V
+5V: 5.08V
+12V: 12.29V
-12V: -16.56V
-5V: -6.51V
+5V: 5.03V

GPU: 49C
Temp3(CPU): 23C
Temp1(Case): 33C

The negative voltage rails seem way off. Can anyone make sense of this data?


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## ggonzalez777 (Oct 6, 2009)

Hey everyone, I'm starting to suspect that the smell was just the PSU in a burn-in stage. The smell is almost not apparent and the CPU fan is rotation a nice 1500rpm. Thanks everyone for your help. Oh, and if anyone was interested I found some really awesome and useful info on the negative voltages. Basically, according to howstuffworks.com:
" -12 V: This voltage is used on some types of serial port circuits, whose amplifier circuits require both -12V and +12V. It is not needed on some newer systems, and even on older ones not very much is used, because the serial ports require little power. Most power supplies provide it for compatibility with older hardware, but usually with a current limit of less than 1 A.
-5 V: A now archaic voltage, -5 V was used on some of the earliest PCs for floppy controllers and other circuits used by ISA bus cards. It is usually provided, in small quantity (generally less than 1A), for compatibility with older hardware. Some form factor power supplies such as the SFX no longer bother to supply it (systems using the SFX power supply are intended not to have ISA bus slots).
0 V: Zero volts is the ground of the PC's electrical system, also sometimes called common or (especially in the UK) earth. The ground signals provided by the power supply are used to complete circuits with the other voltages. They provide a plane of reference against which other voltages are measured.
+3.3 V: The newest voltage level provided by modern power supplies, it was introduced with the ATX form factor and is now found on the ATX/NLX, SFX and WTX form factors. It is not found in Baby AT or older form factors. Originally, the lowest regular voltage provided by the power supply was +5 V, which was used to provide power to the CPU, memory, and everything else on the motherboard. Starting with the second generation Pentium chips, Intel went to a reduced 3.3 V voltage, in order to reduce power consumption as the chips got faster. This required motherboard manufacturers to put voltage regulators on their boards to change the +5 V to +3.3 V. The regulators produced a great deal of waste heat and having to do this reduction on the motherboard was very inefficient, so now the power supply provides +3.3 V directly. It is used to run most newer CPUs, as well as some types of system memory, AGP video cards, and other circuits.
+5 V: On older form factor systems (Baby AT and earlier) , this is the voltage used to run the motherboard, the CPU (directly or indirectly) and the vast majority of other components in the system. On newer systems, many of the components, especially the CPU, have migrated to the lower +3.3 V described above, but the motherboard and many of its components still use +5 V.
+12 V: This voltage is used primarily to power disk drive motors. It is also used by fans and other types of cooling devices. It is in most cases not used by the motherboard in a modern PC but is passed on to the system bus slots for any cards that might need it. Of course, drives are connected directly to the power supply through their own connectors.
Note: You will sometimes see the different voltages produced by a power supply refered to as "rails". This term comes from the world of electronics, where it refers to a long metal bar or strip that is used to provide a particular voltage level."

Very interesting!!!!!


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## greenbrucelee (Apr 24, 2007)

I have never owned or fitted for a customer a psu that smelled of burning when it was burning in, however the smell you described sounded exactly like the psu story I described earlier on in this thread and that PSU was failing.

But aslong as you are happy with it and have the issue sorted I am glad.


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## ggonzalez777 (Oct 6, 2009)

Well I'm still suspicious. I'll let it run for a week or so. I just don't understand the why the voltages look OK even with it smelling like it does. I will definitely redo my thermal paste.


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## dai (Jul 2, 2004)

the voltages can be ok the problem comes when there are not enough amp output on the 12v line

what model unit is it


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## greenbrucelee (Apr 24, 2007)

dai said:


> the voltages can be ok the problem comes when there are not enough amp output on the 12v line
> 
> what model unit is it


Dai it's a coolmax, we both know it'l cause trouble I am just trying to convince the op that it will.


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## ggonzalez777 (Oct 6, 2009)

I'm convinced. I'm going to remove my PSU today. The last thing I need is a fire or my computer blowing up. I guess I can live without my PC for some months. Maybe I'll catch up on some shows or life. LOL.


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## greenbrucelee (Apr 24, 2007)

ggonzalez777 said:


> I'm convinced. I'm going to remove my PSU today. The last thing I need is a fire or my computer blowing up. I guess I can live without my PC for some months. Maybe I'll catch up on some shows or life. LOL.


It's a good move even if this isn't your main issue, like you said you don't want your compouter to stop working altogether.

People tend to see wattage when they are buying power supplies and don't realise about the amps etc and they also forget about how good the components are inside the psu.

I always think of it this way...I like cream pies do I want the one that is cheap and when I bite into it all I can taste is pastry that tastes like crap and will make fart all day long or do I pay a bit extra and get the one with lots of cream and pastry and know that I wont spend all day on the toilet


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## Phædrus241 (Mar 28, 2009)

Oooh! Ooh! The second one! Yeah, that one!


The PSU is one of the most important parts in the computer, but we have a hard time convincing people of it. Never shirk on the power supply. A cheap power supply can start failing shortly after installation if you're putting any kind of pressure on it at all, and can cause problems like:
Dying graphics card VRAM
Overheating due to bad voltage
System RAM errors
Hard drive failure
Random shutdowns and freezes
Sub-standard performance
Issues booting
Failure to start at all

Not to mention lousy efficiency and cooling. Also, some power supplies can't deliver their rated wattage, either because they've inflated their power ratings by over-speccing the 5V and 3.3V rails, because it was tested at 25C instead of a more realistic 40-50C, or because they're outright lying. Or all three.

And when it fails completely, a cheap one can destroy every component in the computer with a burst of "dirty power". Or, with very, very low-end power supplies, they'll explode. It's usually not more than just a burst of sparks, and rarely sets the computer (let alone the house) on fire, but it still is *not* something you want to happen.


So we recommend Corsair and SeaSonic as some of the best power supplies for the money. Stay away from any PSU that is sold for less than two thirds the price of a Corsair of the same wattage, as it is almost guaranteed garbage. If it costs less than half then its only use is as a doorstop or bookend.


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## dai (Jul 2, 2004)

still post the model


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## ggonzalez777 (Oct 6, 2009)

Thanks guys, I'm looking into the Corsair 650W PSU. It'll give me some room so i can add another HDD, I eventually want to make this PC into a media center.


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## FreoHeaveho (Aug 22, 2006)

Great PSU. good luck


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## ggonzalez777 (Oct 6, 2009)

I did the inevitable. I took out the power supply then took it apart. Well, it seems that the smell was from the triacs that switch on and off the input AC voltage. I suspect that they could not handle the current that i was drawing from all my components. I'm ordering that new PSU on Thursday. I'll keep you guys posted. I really hope that's the root cause of my issue.


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## dai (Jul 2, 2004)

you need to be careful opening power supplies they can carry a lethal dose weeks after being disconnected


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## ggonzalez777 (Oct 6, 2009)

Hey everyone I just bought the Corsair CMPSU-550VX 550-Watt VX Series 80 PSU since my needs have changed. My gf's computer will now be the media center computer and mine is going to be a normal online/music production computer. Can't wait until it arrives to install it!!!!


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## greenbrucelee (Apr 24, 2007)

cool, good luck


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## ggonzalez777 (Oct 6, 2009)

Hey everyone, guess where I'm typing from???? From my Corsair CMPSU-550VX 550-Watt VX Series 80 PSU powered computer!!!!!! So far so good, I'm really glad I came to this website. I would have kept making the same mistake and buying crappy low quality PSUs. Thanks again everyone for your help. Oh one last thing. My CPU fan continues run high. It goes away when I restart the computer. Almost alternately. Like right now its really quiet and my CPU is at about 37C. If I restart or come out of sleep mode, it will start to run high and my CPU will start to get hot, to 69C occasionally. I did redo the the paste on my CPU and cleaned the fans.


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## dai (Jul 2, 2004)

they do jump when restarted and drop back usually not by that much

check you applied the paste correctly

http://www.arcticsilver.com/arctic_silver_instructions.htm


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## ggonzalez777 (Oct 6, 2009)

Well, I did apply the paste correctly. But believe it or not I am STILL getting that burning smell. I guess there might be a problem with my mobo.


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## dai (Jul 2, 2004)

try smelling through a straw or piece of plastic pipe to try and isolate where it is coming from


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