Ian Malcolm wrote:
"David Farber" wrote in
:

There was a power surge at the customer's house. PG&E said their
neutral line failed. The computer now has an ATX power supply that
smells quite crispy. The 6.3 amp fuse was blown. I replaced it, then

then smoke came pouring out of one component which was shorted. It's
located between the largest two capacitors on the board which are
470uF @ 200V. I was able to peel off the heat shrink and it appears
to be a ceramic disk capacitor. The part number starts with 241k. I
cannot read the other numbers that follow. I'm guessing it's 240pF
but at what voltage? It's wired in parallel to the previously
mentioned largest capacitor on the board. Any idea what the voltage
rating should be on this cap? Is it even necessary to replace it?
The power supply works fine now that the short has been removed.


Its *NOT* a cap, its a varistor and is supposed to clip any spikes on
the AC in. Replace it with one rated for continuous operation at your
local supply voltage or the next time there's a surge the PSU will
puke its guts and is quite likely to take out the motherboard and/or
hard drive. There may be one across the other big cap as well and if
so they should be replaced as a pair. Its essential to replace the
heatshrink (and make sure its non-flamable) or the next failure will
deposit a conductive coating over the rest of the PSU.

Thanks for that info. I'll remove it from the pc until I get the correct
parts. You are correct, there is another one of these across the other big
cap.

--
David Farber
Los Osos, CA