Daddy, why does it smell like fire?
So on Sunday morning my daughter runs up to me and asks me why it “smells like fire.”
“FIRE?”
“Yes fire, weee, let’s find the fire! Fire fire fire, woohoo!”
Should I stop reading my book? Run? Panic? Let the house burn down, collect the insurance money, take a hippie name and start a farm?
After a couple of minutes we narrow down the fire smell to my office. Oh shit! I start smelling the backs of my computers, the power supply fans. “GOOD LORD NO!!! NOT MY COMPUTER, NO NO, BURN MY WIFE’S COMPUTER INSTEAD!!!”
Alas, it was my computer. But at least not the main computer, so I count my blessings. At this point I don’t even know what the hell burned, though the computer is dead (turns on, PSU fan comes up, nothing else). I open up the bugger and start looking for some blackened component but find none. No signs of damage. I start smelling all over the motherboard, hard drives, processor, snorting up all sorts of carcinogens and shortening my life by at least a couple years, but it’s all uniformly stinky as far as my nose can tell.
I always buy good power supplies, this one was a ~500W HIPER, sure looked high quality to me. You know, HIPER quality. I’ve never had anything like this before, so not sure what to think. I wonder if all components are damaged. Is this a PSU failure?
January 12, 2009 at 11:18 pm | Filed Under Personal
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28 Responses to “Daddy, why does it smell like fire?”
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Scary! Glad that you were home and could shut down the computer in time.
@HAL: seriously!
I wonder though what would have happened had I _not_ shut it down. My guess is that it would have been ok, ie, it shorted, burned something, put out the smell, stopped (perhaps because the failed component burned and cut the short?).
I’m not sure though, definitely glad I was home.
It’s pretty rare for components to literally burn in a PC. But, some of them get pretty hot. A failed heatsink fan might allow your CPU or GPU to take the short leap from working properly to molten silicon, especially some of the modern GPUs. I can’t believe they run as hot as they do just sitting there idling. If my CPU hit temps like the GPU does, I’d be panicking.
That would also explain why there’s nothing visibly burnt. The corpse is hidden under a heatsink.
One of my scarier computer moments happened in the middle of the night. I was online when suddenly my screen went dead. I stared at it in puzzlement for a second, looked left at the computer to see if the light was still on and saw black smoke pouring out of the back of the computer.
This was a bit alarming.
Fortunately yanking the power cord caused it to stop, and upon dissection it turned out that what had happened was the motherboard had got very dusty and it had caused a capacitor to explode (or at least melt dramatically).
I ended up reusing most of the system, only replacing the motherboard (I was a penniless student at the time), but I wouldn’t recommend this – the computer was never the same after that, and the slow slide into complete hardware death over the next year was a really frustrating process.
If the fan runs, it couldn’t be the power supply — right? But it is odd if the disks aren’t spinning.
Are there any lights on any of the boards inside?
Glad you were home, in case it might have caught something.
In my experience if the only things that smells like burning in a PC is the power supply. That’s because of it’s rubber/plastic components.
Try hooking up another one to the motherboard and see if you still smell anything.
In my experience PSU’s usually die from dried up capacitors,damaged resistors or bad solder joints. Capacitors degrade due to electrolyte evaporation which is temperature dependent, but eventually inevitable. Resistors also take some beating due to temperature. Solder joints can eventually crack after many temperature cycles.
When either of these dies , the surrounding components either die with them ( causing overheating , which in combination with aggregated dust is bad, causing at least bad smells , in the worst case fire ) or are just disconnected from main supply, causing a general PSU failure.
It’s all due to engineering specs in the end. These days, they don’t build PSU’s like say in the eighties.
In my experience, a faulty PSU in 30% of the cases also kills at least the hard drive and any cd/dvd units. Motherboards seem to be more resilient due to voltage regulators on the board itself.
@David, dust doesn’t cause a capacitor to explode. The capacitor dried out, eventually causing a short-circuit causing it to “explode”. Dust is usually harmless, unless you’re in a industrial environment , like a steel mill, where it actually conducts electricity, due to iron/carbon particles
I had a similar experience with one laptop, an IBM R51, which had some sort of short-circuit that melted some components and put a hole through the motherboard. No repairing was possible – only MB replacement which is too expensive.
Thanks for the feedback everyone
@David: that was funny. I’m sorry it happened to you, but black smoke coming out of a computer is pretty amusing
I did look closely around the CPU, northbridge and southbridge but didn’t see anything that looked like damage. The video card was low end since I don’t game. In fact, that was a Linux box that never saw a graphic in its life.
Regarding the PSU, right, I wondered too about whether it could have ‘failed’ given that its fans still came up. What I thought was something like… some PSU component failed, shorted or something, gave out the burn smell and killed the motherboard in the process. However, it didn’t take out the PSU entirely. I’m not sure if this makes any sense, I’m 100% ignorant about how PSUs work, but I wondered if that was a possible failure mode.
What was strange to me was the lack of visible signs of damage, despite the STRONG olfactory signs. heheh. The corpse under the heatsink idea makes sense to me, though I did check the heatsinks closely and saw nothing.
The capacitor idea also makes a lot of sense. Ie, it was NOT the PSU, but rather an MB capacitor. But then I would expect something _visible_ like Ovidiu described.
Re: the hard drives, they were OK, thankfully!
I have had problems in the past with bad motherboard capacitors on a Gigabyte motherboard. If I recall correctly that specific board was bought in 2002. I think the manufacturers are using better capacitors these day however.
Check out http://www.badcaps.net/ to see examples of burned motherboard capacitors.
My experience of faulty capacitors is that upon failure, they usually swell, distort, come apart or literally blow to pieces! As for the PSU cooling fan, it would depend on where it gets it’s feed from. If it’s from the secondary (low voltage) side of the PSU it will fail with the PSU, but I have seen some units where the fan gets it’s supply from the primary (input side) of the PSU too. In the latter case, the fan could continue to run as long as the fuse in the supply cord remains intact.
Another common reason for PSU failures can be the ‘chopper’ transistors which often fail short circuit and then heat up extremely rapidly till they explode. This short circuit can cause a lot of other components in there to overheat as the extra current drawn burns them out.
One other possibility is that one of the output ‘rails’ has failed. The low voltage side of these modern PSUs is capable of providing very large currents. The net result would be one or two of the output voltages would be absent, leaving the others OK. If the motherboard looks all OK, I would start by trying a new power supply, and work inwards from there.
As another quick thought though, if the power supply proves to be faulty, and happens to be within it’s warranty period be sure to claim it! As for failures, I live in a rural area in the UK and we get a lot or power lines blown down etc. what tends to happen is that when the power goes out, the distribution tries to reset itself a few times so the power comes on and goes back off rapidly a few times before staying off. I’ve lost a good quality PSU because of these surges on one occasion and an entire TV set on another!
@Andrew: thanks a lot for the input. Your point about the PSU cooling fan makes sense. I’m now thinking that’s the most likely scenario, that something failed _within_ the PSU, explaining the burn smell and the lack of visual signs (because I can’t see inside the PSU), but the PSU cooling fan is still going.
I’ll look into the warranty for the PSU.
cheers
It’s entirely possible for something to fail in the PSU causing your motherboard to be ruined but the PSU still managing a marginal level of usability afterwards.. not a total failure of the PSU..
Try a new PSU, see what happens. I haven’t read much about Hiper but I would rather use something else, Enermax, Silverstone, Seasonic, or a high end Antec
“I ended up reusing most of the system, only replacing the motherboard (I was a penniless student at the time), but I wouldn’t recommend this – the computer was never the same after that, and the slow slide into complete hardware death over the next year was a really frustrating process.”
I’d say all your problems came from the PSU in the beginning, probably due to bad output voltages or high ripple.
The first board probably blew because the cap dried up due to high ripple from the PSU and possibly bad quality in itself.
2nd one may have been more resilient but the PSU would have been giving it enough bad power to cause it run less than perfect
@Agent: thanks a lot for taking the time to explain this stuff. My intuition wasn’t entirely off then, that’s good to know.
I do usually buy Antecs. At the time this Hiper seemed like a good quality modular PSU at a competitive price, so I went for it. Looks like it was the wrong bet.
I had a similar experience, waken by a headache, a strong smell and a strange clicking noise I discovered my computer was turning itself off and on in a continuous cycle.
It had been shut down before I went to sleep.
Replacing the motherboard (my first suspect) instantly killed the replacement board (powering up on it’s own, then .. nothing)
My curiosity eventually won from my desire to claim any warranty, so I opened the PSU and found some interestingly dark components.
http://boiert.eu/zooi/antec/
The only components that survived this ordeal where my floppy drive and the RAM. The motherboard, cpu and graphics card are gone forever.
I had an Antec 300W power supply die after five years. Eventually even the “best” products do fail.
Every once in a while I also vacuum (yes, vacuum) out my PC. Even though my PC is on my desk and not on the floor, it accumulates dust that tends to clog up the CPU heatsink. Less likely, but possible, is that accumulated dust could cause a short-circuit.
On PSUs: they emit a bunch of different voltages (one reason for the weird connector) and I have seen damaged PSUs that won’t power a PC due to a certain voltage output being gone, but otherwise OK on the other voltages. Sometimes a power “spike” or glitch from the grid will come into your home, and if powerful enough could also damage your PSU, so having surge protection is a good idea. One time I had a power spike at university that literally shook my Belkin “Surge Master” like it was a BLENDER (which I suppose was due to it dissipating the surge.)
u guys r nerds
Some of the cheaper Antecs use Fuhjyyu brand capacitors, which are widely considered to be bad quality. They might have switched to Teapo now, not sure. (but those aren’t that great either). Their BasiQ line of PSUs is one of these examples.
Of course even the high end PSUs fail, everything does. However, with no other faults present, the capacitors will die first simply due to age. This is not helped if the PSU runs hot.
If the PSU is well cooled, their life will be much longer. However in the case of really rubbish capacitors, they can can go bad by just sitting brand new in the box, because they are simply that bad.
If you’ve got a good PSU that is let down by mediocre capacitors, just replace them with something decent. Then it will last many more years.
However, without visual confirmation (capacitor vented\leaking\bulging) it can be hard to determine if it is the problem. Often they fail before they show visible signs, often they dry out instead, and will never bulge, but have still failed.
An ESR (equivalent series resistance) tester is usually the best way to tell if a capacitor is bad, however some will pass this test and yet be faulty due to a major drop in capacitance instead. Very rare but not impossible!
@Ben: Pretty unlikely that dust in your CPU fan will cause a short circuit. Dust buildup to the extremes is going to cause overheating though. If the dust was damp you could get high resistance paths through the dust where current should not flow… probably won’t cause a short either but may lead to strange intermittent problems
(Motherboards coated in cigarette smoke residue can appear completely failed, however once cleaning all the gunk off, work perfectly)
I HAVE LEARNT ALOT THANKS
I had a similar problem, though my computer still works the same as before.
I’m much of a gamer, so my computer is kinda hot at times.
I had left it off for two days (I turn it off on weekends ’cause I’m not home, the rest of the time it’s on.
So, it started to smell smokey, but at first I thought of the house’s radiators(forgot the good word)
Then, while I was playing, the computer turned off suddenly, so I checked it with more concern.
Turned out the power supply was damned hot. But the computer started normally afterwards.
Anything I should consider checking even though everithing seems to work fine ? (I even played that same game without any problems after.)
So, I have this Dell gx270 with bad caps. There are numerous visually bad caps but the PC runs (albeit slow). The power supply is VERY hot.
1. Could the bad caps cause the power supply to run hot?
2. Could the hot power supply cause the caps to faile?
3. Could it be a mixture of the above?
Btw, I did see a motherboard catch fire. I was checking out a customers PC with the case off, and when I turned the PC on, it would spark (I think near the BIOS chip). I did this a couple more times and it did actually catch fire.
I also accidentally dropped a screw into a mother board while the PC was plugged in but not powered on. It shorted out a connection and a small circular piece of the ceramic covering of a processor popped right up into the air. I could see the little proccessor in the open hole. I always unplug and wait for the led lights to go out now before doing anything inside a PC.
@ChrisF the bad caps will cause the psu to supply more current than normal therefore get hotter than normal, also if it is hot this will tend to dry out the caps!!!Chicken and eggs!!!!
also if it is hot this will tend
to dry out the caps!!!Chicken and
eggs!!!!
Which caps will tend to dry due to heat? Any direct relationship between power supply failure and dead/blown/bulged capacitors. What effect does both have on each other?
Oh boy HIPER is not a good name for buying PSU.How can you forget PC power and cooling and also corsair?
I saw this way late, but man I can tell you I’ve been there… know that feeling, and now that all my IP is in Google Apps I feel a bit easier about the scene. Lee (a.k.a. magnum 6 out)
atleast its not your main computer that was burned. Maybe it’s the power supply that started the fire and the fan is not working. a power supply needs a fan to control it’s heat release and maybe the capacitor started the fire because of the heat.
Substitute the PSU I have had this happen a lot over the years they can still output power when the other half is dead
9 times out of 10 it will be the psu. If that doesn’t work try removing ALL the add on cards from the MB and try again. Hope you get it sorted.