Dust-laden PSU catches on fire - Page 1
Forum section: electronics / general

author: Phaedrus
author_rank: Frequent Contributor
timestamp: April 01, 2014, 10:50:06 pm
content: http://youtu.be/XTKCPMgn8J4?t=1m59sCrappy design + half a decade's worth of dust = real, literal flames.

author: TVman
author_rank: Frequent Contributor
timestamp: April 01, 2014, 11:15:05 pm
content: Folks, you need to dust out your computer or like in that video it will catch onFIRE!So dust out your computer AND power supply once in A while. PLEASE!!

author: Kryoclasm
author_rank: Regular Contributor
timestamp: April 02, 2014, 02:02:01 am
content: Don't computer PSU's have thermal overload protection?As an IT computer manager more than 10 years ago I have worked on hundreds of desktops and some that were clogged waaaaaay worse, yet no fire.Has anyone personally seen a computer PSU fire or results of one outside of a fume hood?

author: Phaedrus
author_rank: Frequent Contributor
timestamp: April 02, 2014, 03:17:36 am
content: Quote from: Kryoclasm on April 02, 2014, 02:02:01 amThis one was a piece of crap Won Hung Lo brand with no OTP, which was being loaded near its maximum capacity with a DC load bank. So not your everyday occurrence. But it can happen.

author: TMM
author_rank: Frequent Contributor
timestamp: April 02, 2014, 04:58:51 am
content: If it's a cheapo PSU it probably couldn't even handle 350W when it was new, hence why the supply fails and the fan stops which in turn allows it to catch fire. Realistically a cheap one hung low '350W' psu is 150-200W at best.

author: retiredcaps
author_rank: Super Contributor
timestamp: April 02, 2014, 06:06:42 am
content: One of my friend's el cheapo 200W "Sun" brand caught on fire a couple of years ago. The place he lived in was really dusty and the PSU caught fire. He gave it to me for post mortem and the pcb was charred. I think I salvaged a couple of the bigger resistors, but everything else was recycled.

author: nctnico
author_rank: Super Contributor
timestamp: April 02, 2014, 10:51:34 am
content: Quote from: Kryoclasm on April 02, 2014, 02:02:01 amNot a computer but I've personally seen the boards of a TV catch fire without any trickery. It was age combined with dust.Temperature protection won't help. It is not the hot heatsinks which catch fire but it is the PCB or glue in combination with bad solder joints. I recall repairing a power supply in which the glue to hold down a component got slightly conductive.

author: GreyWoolfe
author_rank: Unknown
timestamp: April 02, 2014, 12:29:20 pm
content: On my last job, I did Dell and Compaq in home warranty work. I serviced literally 1000's of computers and never saw anything like that. I saw many that were much worse as far as dust and am sure there were plenty instances of dust arcing that damaged boards but no fires. Interestingly, one of the worst computers for being dusty/crusty was at a dentist's office. I removed the bezel and the dust was solidly caked at the vent holes and it pealed off in a sheet. The inside was just as bad. Of course, overall the worst was computers in a house with smokers.

author: ConKbot
author_rank: Super Contributor
timestamp: April 02, 2014, 12:34:14 pm
content: Quote from: GreyWoolfe on April 02, 2014, 12:29:20 pmI'm guessing that PSU voltages were way outside of spec when it was loaded and the transistor popped. If the load were a PC, it would have either reset/crashed before loading the power supply that much, or it just flat out wouldn't boot. Thats when it would get sent into you, dusty, but not charred.

author: VK3DRB
author_rank: Super Contributor
timestamp: April 02, 2014, 12:50:43 pm
content: Strange how he just happened to be filming it. Looks like it could bebut I have no proof. If it is not a hoax, the PSU certainly did not have any UL approvals.We hear all too often of dodgy ceiling fans catching fire. One friend of mine had his bathroom sustain serious fire damage because of some Hoo Flung Dung brand of ceiling fan that some clown brought into the country. About $10,000 damage to his bathroom and smoke damage throughout. You get what you pay for, but he did not count on it catching fire!Western governments should adopt strict rules to prevent dangerous rubbish entering the country, rather than turning a blind eye to it all.

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: April 02, 2014, 12:52:57 pm
content: I've had a PSU "explode" before. System was running and I went to bed. When I woke up it was powered off. It was on a UPS, so that shouldn't have happened. Tried the power button, got nothing. Flipped the PSU switch off and back on, and pressed the power button. The resulting bang almost made me crap my pants, because it was 4:30 in the morning, and the room was really quiet. Took it apart afterwards and saw that one of the transistors blew out. Wasn't overloading it or anything, I can only guess it was old age.

author: hans
author_rank: Super Contributor
timestamp: April 02, 2014, 02:33:36 pm
content: The real question is.. What was the supply rated for?If it's a low-end brand, don't expect it to deliver full load 100% duty cycle 24/7. Even if this supply operated at full load for 3 minutes, those cheapies are probably specified at something they can deliver for <10s, just like a some multimeter fuses can take 20A for 10s every x minutes.Shame there is no protection though. I can image someone running a bitcoin farm on such a supply, full load GPU(+CPU? server maybe?) and the thing catches on fire while he is remotely connected. Oops..

author: ConKbot
author_rank: Super Contributor
timestamp: April 02, 2014, 04:10:12 pm
content: Quote from: hans on April 02, 2014, 02:33:36 pmWhy expect garbage? If I have a 350W power supply, in open air like that (I.e. no extra heat load from a PC blowing into it) I'd fully expect it to put out 350W 24/7. Sure, service life wont be the same as if it was running at 60%, but I expect it to cope for some period of time.A 10s burst is a useless rating, when I start playing a game and the GPU loads the power supply heavily, it sure isnt doing it 10s at a time. The junk power supplies that you get for $cheap are just plain over rated for what their actual capacity is. No need to get duty cycle or load duration involved.As others said, from a 350W supply, dont expect more than 150-200W if you bought the power supply for cheap.

author: G7PSK
author_rank: Super Contributor
timestamp: April 02, 2014, 05:19:39 pm
content: I have a Medion brand computer that came from a dog groomer's the fans were so clogged that the windings on the graphic card's fan had burnt out to the extent that the board was charred. replaced the fan after a good clean and the machine is fine.

author: Len
author_rank: Frequent Contributor
timestamp: April 02, 2014, 07:34:23 pm
content: Quote from: VK3DRB on April 02, 2014, 12:50:43 pmNot strange at all IMO, that was probably the only time the PSU was ever subjected to its maximum rated load. It's not uncommon for a PSU to fail in that type of test, many are "optimistically" rated. If you look at reviews of PSUs where they actually load-test them, they fail sometimes. (But usually without smoke & fire.)

author: GEuser
author_rank: Frequent Contributor
timestamp: April 03, 2014, 08:03:30 am
content: In the Vid one can hear something pop and see the area where it comes from , it looks like whatever poppedthen ignited the dust collection , but I tells ya what I thinks whoever that was was slightly gung ho on grabbing the power supply to unplug the cord imo ..