In alt.comp.hardware.pc-homebuilt larry moe 'n curly
PSUs are supposed to be able to stand direct shorts, and the Antec
SmartPowers I've accidentally shorted never seemed to suffer.
They're *supposed* to.
They have shutdown circuits that are supposed to protect them.
I had an ATI video-card *really* short out bad on me one time.
I mean really *really* REALLY bad.
My first suspicion of trouble was that the PSU was bad, since the whole
system was completely dead and not the slightest flicker of light when
powering up.
It was ... bad.
It failed to even power up my cheapie PSU tester with the lights.
I replaced it temporarily with a "known good" PSU, as a check.
Immediate shutdown!
At least *that* indicated that:
A. There was some kind of short on the computer itself.
B. The original PSU was now bad because of the short.
So ... I investigated further by pulling ALL boards out.
I then found it was the video-board that had crapped all over
everything.
As a (rather stupid) check or verifying, I stuck the bad card in another
(working) computer; figuring the protection on that PSU would save
everything if the board was truly shorted.
The motherboard saved the PSU by blowing a trace ... AFTER which the PSU
finally shut down.
Luckily I was able to find, see, and replace the blown trace on the
motherboard.
OK ... So I got a new and much better video-board.
For some reason it took *three* tries before the new system would power
up properly. But it did; and my main computer was running again.
Also, after putting back the original video-card on the other computer,
it also ran just fine.
.... For about a week.
Then my main computer, the one with the new video-card in it, crapped
out completely. A test with the PSU-tester showed a dead power-supply.
It seems the temporary short when trying to find out if it was
power-supply or short had weakened the PSU so it failed within a week.
Guess what?
Three days later, so did the PSU on the other test computer.
THREE different power-supplies sent to the scrap-heap by one shorted
video-card! (Also, a motherboard *almost* scrapped.)
BTW: All three power-supplies were completely different makes, ratings,
and models; 350, 400, and 550 watt supplies. It was the 550 watt supply
that creamed the motherboard.
So don't trust a PSU to stand up to shorts.
They're *supposed* to; but that's a different story.
Somehow I suspect that actual TESTING power-supplies by shorting them
out just isn't one of the things they do at the manufacturing plant.
If one "survives" for a few minutes after short in design-verification,
then they ass-u-me that the design is OK. ;-{
