Bad smell coming from computer but no high temperatures.

[victor.marteolympus]

Last week I noticed a bad smell coming from my PC. Not exactly a burning smell: kind of, but not quite. At the same time I noticed the fan of my PSU was not working properly, it staggered at times, so I figured that it was the PSU that had broken. A few days later I replaced the PSU with a brand new one (and cleaned the rest of the interior of the PC, just in case), and lo and behold, the smell still was there.

The next thing I thought could be the culprit was the thermal paste, because I had applied a very cheap one more than a year ago. This morning I noticed a small bundle of dust in between the CPU and the heatsink and removed it, then I replaced the thermal paste using a better brand. The smell still persists.

I've checked all the temperatures I can (CPU, GPU, HDD, SSD, Mobo (in the BIOS)) and everything seems within its normal range, even at full load. I can boot up the PC and it runs perfectly as always, even when playing a resource-heavy game or when rendering a 3D model.

The smell seems to appear only when the PC is running. If I turn it off, wait a few minutes, and smell directly into the case, I can still notice it, but much less intensely, around the zone near the CPU and the back panel of the motherboard.

I think the smell is not as bad as when I first noticed it, but I'm not a 100% sure.

The only thing left I can think of is that some component in the motherboard is overheating (and it does not show on the BIOS). I've checked visually, but everything seems in order, no bloated capacitors neither spilled liquids.

Any idea what could be wrong, or how could I find out?

My specs:

Windows 10 Home 64-bit
CPU: Intel Core i7 4790K @ 4.00GHz
GPU: AMD Radeon HD 7950 (Sapphire/PCPartner)
Mobo: ASUSTeK COMPUTER INC. H81-GAMER (SOCKET 1150)
PSU: Corsair VS650 650W 80 Plus White

 

[Barty1884]

BIOS/Software sensors are not going to catch things like overheating VRMs etc.

Could it simply be dust? Burning/warm dust isn't going so smell great.

Blow out all dust you possibly can, and see if the smell persists.

Given the location you've been able to sniff out thus far (near CPU socket/rear IO), you're looking at VRM territory.

But, on a board that cannot overclock, the VRM should be more than capable.

 

[R4DIO4CT1VE]

mmmh something crawled behind the motherboard and died? could also just be dust as a previous response mentioned.

i would a take another look around the socket for burnt components, other than that i would say get some canned air and blow any dust out, maybe even take all components out to get them shiny clean all around if you want to.

 

[drivinfast247]

Could be the smell of the dielectric from a failed capacitor. Check the board for ruptured caps.

 

[victor.marteolympus]

I've cleaned all the dust I can, and I still notice the smell. I don't see anything broken or burnt. I guess the only thing left to do is bring it to the store where I bought the parts so they can take a look. Fortunately it is still under warranty.

 

[larrycumming]

warranty is a good thing

 

[TerryLaze]

I'm not trying to scare you or anything but I had a weird burning smell as well and couldn't figure out where it came from until...

Yeah,the back of my PC bursted out in flames...luckily I was in front of my PC instead of sleeping while something downloads or something,so I turned the power off right away.
Everything still works after changing the cable ,only windows needed a reset because it refused to load up after the violent shut down.

 

[victor.marteolympus]

Update: I returned my motherboard via RMA and bought a new one. I've just installed Windows again, and the smell it is still there....
I don't know what else could it be...

 

[Barty1884]

If I were you, I'd disassemble the system. Have the PSU a distance away from the board, and turn the system on. Try to isolate where the smell is coming from.

Chances are, at this point, it's the PSU. Either dust inside, or from a capacitor in the PSU.

 

[victor.marteolympus]

If I were you, I'd disassemble the system. Have the PSU a distance away from the board, and turn the system on. Try to isolate where the smell is coming from.

Chances are, at this point, it's the PSU. Either dust inside, or from a capacitor in the PSU.

The PSU is brand new, and I detected the smell before replacing it, so I very much doubt it's the PSU.

 

[Barty1884]

Ah, sorry - I forgot you'd replaced the PSU.


I would still disassemble. Use only MB+CPU+RAM+PSU, outside of the case. Keep all other components far away.
See if the smell persists.

If not, add back a component, one at a time (again, keeping all others far away). I'd probably start with the GPU.


You want to remove the case from the equation too, just incase it's some dust build up somewhere that's gettign warm, causing the smell.

If you add back all components (outside of the case) and the smell does not reappear...... You're looking at either the case, or the location of your tower.

 

[limsgp]

check the Cables?