Please Help - Burning smell then system shut down.

[WestonG]

Hey,

I built my first system around 6 months ago:

Phenom II x4 965 be

Asus M5A78L LE

8GB Kingston Hyper X

XFX HD6850

500GB Hitachi Deskstar

450w PowerCool Modular

The system ran like clockwork for around 6 months - no problems what-so-ever. Until, one day I was playing a game and noticed a smell of burning plastic/rubber. I immediately switched the system off and removed the PSU. I am aware the PSU I bought isn't a good brand and was quite cheap. Also, I am aware that the cause of most burning smells comes from PSUs.

So, I returned the power supply and waited for a response. Some time later I received an email stating that the PSU had been tested, and no fault has been found. I phoned the company and they confirmed this. I arranged to have the PSU returned.

After a few days I received my PSU through the post. I decided that I would would put it back in my system and try to locate the source of the burning smell. After doing this, I discovered that the smell was not coming from the PSU at all.

The smell seemed to be coming from around the CPU heatsink fan, so I decided to test the CPU and check the temperatures:

Idle - 36-40

Gaming - 50-55

Full Load - 60-65

These temperatures were normal, and similar to what I had recorded over the past 6 months. Also, the system seemed to be running fine. No crashes or anything like that. However, shortly after this my system shut itself down. I tried to restart it to no avail. All I get is around a second of life from the case fans and LEDs

I decided to take everything apart and set it back up outside the case with only the CPU and Memory installed. I plugged in the small motherboard speaker, connected the power supply and switched on the power. The small LED on the motherboard lit up green. When I short the power pins, I get around a second of life from the CPU heatsink fan. I get no beeps what-so-ever from the motherboard speaker.

I also checked for signs of burning or damage anywhere on the motherboard or components. I cant find any visible signs, nor can I smell the burning smell that was present when the system was on.

I really don't know where to go from here. I don't know how I can identify exactly what the problem is.
After they found no fault in my PSU, the company told me they would have to charge me if I return another working product for testing. Any ideas as to what the problem may be, or how I can identify which component is causing the issue would be greatly appreciated.

Thanks in advance -
Weston

 

[christop]

Man that sound just like the psu is bad to me. I know you said the company tested it but from my experience it sounds like a bad psu. My sisters computer was doing the same thing except the burn smell. I would hit the power and the fans would spin for a second then shut off. I purchased another psu and installed it and it booted up fine. I would like to know how they tested the psu. I mean did they just use a jumper and short it out to see if it power on or did they check all the voltages.

 

[Onus]

Was it overclocked? A frying VRM might have produced the smell.
Unplug the CPU power cable and turn it on. Of course it won't POST or boot, but if fans continue to run, it may be that a VRM has indeed shorted. If that's the case, you'll need a new motherboard. If the behavior stays the same though, replace the PSU with a quality model. A 380W Antec Earthwatts could run your system.

 

[WestonG]

Was it overclocked? A frying VRM might have produced the smell.
Unplug the CPU power cable and turn it on. Of course it won't POST or boot, but if fans continue to run, it may be that a VRM has indeed shorted. If that's the case, you'll need a new motherboard. If the behavior stays the same though, replace the PSU with a quality model. A 380W Antec Earthwatts could run your system.

At the time I noticed the smell, the CPU was overclocked to 3.6. When the system shut down, it was stock speed. So, you think it is most likely the motherboard? Thanks for your response.

 

[Rahbot]

I would suspect the PSU is the problem and I had the same thing happen to me I sent in the PSU and the company told me it was fine. After I got the PSU back and plugged it back in to test out my system the PSU caught on fire... I then called the company and sent the PSU back and they told me that It was user fault why the PSU caught on fire.... needless to say they wouldnt replace the PSU.. I then bought a Antec 1000W PSU.... never looked back.

 

[WestonG]

Is there a way I can test the PSU for fault? Just to rule it out before I send Anything back.

 

[WestonG]

Was it overclocked? A frying VRM might have produced the smell.
Unplug the CPU power cable and turn it on. Of course it won't POST or boot, but if fans continue to run, it may be that a VRM has indeed shorted. If that's the case, you'll need a new motherboard. If the behavior stays the same though, replace the PSU with a quality model. A 380W Antec Earthwatts could run your system.

Not sure if it's what you ment. But I tried to turn the system on without the CPU but connected to the case. The case fans light up and spin for around a second. Similar to what the CPU heatsink fan does.

 

[Onus]

Well then, it isn't a VRM shorted. It does look like the PSU.

 

[WestonG]

Well then, it isn't a VRM shorted. It does look like the PSU.

I also used the paper clip method to short the PSU. With my case fans plugged into it, I got a similar flicker from the LEDs and a jutter from the fans. At no point did the PSU fan start. It does seem the PSU has died. Do you think it could have damaged my motherboard? Given the burning smell and the shutdown...

 

[Onus]

It is possible. See if you can see a discolored area on the motherboard. Check all the wires from the PSU up to their connectors for signs of melting insulation. The burning smell could have just been insulation, varnish, or dust.

 

[WestonG]

It is possible. See if you can see a discolored area on the motherboard. Check all the wires from the PSU up to their connectors for signs of melting insulation. The burning smell could have just been insulation, varnish, or dust.

I can't see any sign of damage. I think I will just pick up a new, more reliable PSU and hope that this one didn't cause any damage. Thanks for your help.

 

[Onus]

Ok, let us know how it goes.

 

[darkspartenwarrior]

Burning VRM or MOSFETS if it's from the CPU area, I know Gigabyte had some issues with Burning MOSFETS on some of their more Overclocking-oriented boards, not sure about Asus.

But just because it comes from the CPU doesn't mean it's a Mobo/CPU issue, could be bad power or bad regulator caps(bulging/charred caps, or leaking caps, look for them.)