| Started the copy and the screen went blank and the room filled with | smoke. Smelled like burning resistor (I think). I have smelled that | smell before. | The only time I've ever seen that happen was with some kind of short that caused smoke and then soon after a resistor exploded. It overloaded all components, killing the RAM, hard disk, modem, CPU. Do not try to turn it on again. If there's anything left usable it should be removed and oput into a new box if possible. You could try just replacing the power supply, but I wouldn't do that with a valuable hard disk in place.
There is one chipset with a problem, then your source would be motherboard. The Intel ICH5/ICH5R could suffer latchup in the USB I/O area. Causing a short across the rails powering th USB pads. In an unlucky case, the bond wires on the pad with the latchup, remain intact, and a burned spot appears on the lid of the Southbridge. Since the Southbridge in that case, has no heatsink, it's easy to spot when someone tells you where to look.
(What a damaged ICH5/ICH5R looks like...)
But that hasn't happened since ICH5 era - no PCH seems to have suffered a similar fate. So Intel quietly figured it out. Back when those were happening, there might have been around 30 USENET posts from victims... I still own an ICH5, which remains intact. And I treat it like royalty :-)
If you were to take it to Geek Squad, they might well immediately pull the ATX supply, and connect up a spare supply. This is fine, if the spare is a decent name brand supply with full protections (so it can survive whatever the motherboard throws at it). But there might be a flaw which can damage a spare supply (like some rail to rail short maybe).
A question arises occasionally "should I try to use the defective computer again and again to collect more (smoky) symptoms?" . No, don't do that. One poster tried that while debugging his system, and the old flaky supply blew in spectacular fashion, damaging the motherboard. Meaning the repair went from from costing $50, to costing $200.
You can at least start with the "nose" test, and track down where the smoke came from. And PSU is likely to be the source.
Visual inspection only occasionally digs up a root cause for you. But visual inspection is cheap. And visual inspection is safe, *as long as you stay away from high voltage stuff*. The inside of the ATX supply, below the lid with the four screws, has a couple caps that are (potentially) dangerous. They hold enough energy, you *do not* use the screwdriver discharge method on them - it would deafen you if you tried that. Just stay away from them.
There is a reference schematic for a simple ATX power supply design here. R2 and R3 make C5 and C6 "safe". But if R2 or R3 fail open circuit, then the natural draining process provided by R2 and R3, might not actually be protecting you from high voltage. It is C5 and C6 terminals on the PCB, you do not want to touch... Only use a proper resistive shorting technique to make them safe (i.e. connect your own R2 and R3). It's better just to "look but don't touch" while looking inside an ATX supply... And don't forget to unplug the computer!!!
When you visually inspect the inside of an ATX supply, this is what you'd be looking for. I had an Antec, with low service hours, that looked exactly like that. The PC had been sitting in storage, on the main floor of my house (i.e. dry and warm), and the Antec caps started to leak while it was just sitting there. And I got a puff of gray smoke when I fired it up again. The capacitors on the motherboard, can also have domed lids and orange dried deposits on top. And that's mainly what a visual inspection covers. Only about 10% of potential faults are covered by a visual inspection, so it's not a "heroic method" by any stretch of the imagination. But visual inspection is "free" :-)
Of my three failed ATX supplies here, only one of them looks exactly like the Wikipedia article.
Yes. I had the displeasure of locating the source of a burning smell among a collection of immovable servers in a server farm. To make matters worse, there was lots of cooling air flow to disperse the smell. If there was any smoke, I couldn't see it.
So, I stuck a clear vinyl hose in my nose, and waved the other end of the hose around the fan exit ports on the servers. That isolated the smell to one server. I got permission to shut it down. However, when I opened the case, I couldn't see anything obviously burning. So, I did the vinyl hose trick again, and eventually isolated the smoke to the power supply. I didn't want to do component level troubleshooting so I just replaced the power supply.
Somewhat later, I bought am "air quality monitor". It's quite sensitive and will easily detect the smoke from a burning component. That came in handy when I noticed that something smelled like it was burning in my palatial office. I waved it around to sniff the various likely culprits and eventually isolated the smoke to the APC BackUPS XS-1000 in the photo. Notice the bar graph showing tilt.
Here's what's inside the Nikken AQM: Inside IR dust scattering sensor:
Jeff Liebermann firstname.lastname@example.org
150 Felker St #D http://www.LearnByDestroying.com