On 25 Feb 2002 at 19:14, Robert Rolf wrote:

> The 'pro' supplies used in high end boxes have serious 'crowbar' SCRs on
> their outputs to prevent this sort of thing from happening. When you have $10k
> of high performance server/hard drives, you don't worry about $10 of fail-safe
> parts.

I've never seen a supply with multiple crowbars. Usually(like this
one) there is a crowbar on the 5v supply, plus a 339 quad
comparator sensing all supplies. The 5 volt line never got too high, it
was the other supplies that did all the damage. That's why the video
card, ethernet card, and floppy drive survived. Everything else was
toast.

Computer was plugged into a UPS, it wasn't a surge, the power
supply just picked a good time to go full duty cycle. Or perhaps the
crowbar somehow triggered, and it forced everything else up as it
tried to restore +5 to the proper voltage?

Redarding expensive power supplies, I'm not convinced they are
any more reliable. When I bought a system with an Athlon, I
followed the recommendation and bought the best power supply I
could, and went so far as to buy ones on the list at AMD. Three
power supplies from two different brands all failed for various
reasons within a few months. I now have a piece of crap power
supply in it and it's been working three years. The expensive power
supplies were heavy, had lots of nice parts in them, but they were
less reliable.

Cheers,

Bob

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