[geeks] EE question re: Repairing Indy PSU

[Gregory Leblanc]

I need to get a replacemnt varistor for my Nidec built Indy power
supply.  This is down at the AC end of the circuit (before the
transformer).  It's marked KCC 146004, which turns up nothing on the
web.  Do I just guess that a 20mm varistor for 240VAC rms is what I
need, or is there a better way to figure out what to get?


More background:

I got out all of the EE hacking tools last night, so that I could go
about trying to fix my Nidec Indy power supply.  I've read all of the
publicly available reference material on the topic, and, well most of it
sucks.  More specificly, the information that says
1- Check the electrolitic capacitor C1(1uF 400V) and the resistor R5, is
the most frequently failure in that power supply.
2- Check the diode D14 (2 diodes on a TO220 case) and D11, they fails
often.

doesn't appear to be useful, or even entirely correct.  C1 is not an
electrolitic, though there is an electolitic near C1 (it's a 1uF 250V on
both of my Indy's).  D14 appears to be 4 diodes in a case on my board.

Anyway, after some mucking around, I found a fuse (completely burried by
hot-glue) that was blown.  It appears that the varistor right next to C1
is toast (testing with the DMM shows it at 8 Ohms, if that's a
completely bogus way of testing it, somebody let me know).  I'm not
quite sure on how to spec a replacement part, other than to guess at
values.  The markings are KCC 146004, searching on google doesn't turn
up any useful info (except one post which says nothing I didn't already
know).  Do I just spec this part at 240 VAC for the rms, and guess that
whatever is available in the 20mm size is good enough?
	Greg

[demime 1.01b removed an attachment of type application/pgp-signature which had a name of signature.asc]