"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.


--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
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