Switching power supply fry

[Stopp,Gene]

Hey Chris,

Watch out fer them switchers, ya look at 'em funny and they blow up. And
once ya do that, there's little hope of repair, at least not as a
time-is-money proposition....

If you're trying to test it without a load, this might be what you are
seeing. Most switchers need a minimum load in order to come up to their
operating voltages in the first place. When there's no load, they go
into some kind of "idle" condition.

If you are using a test load, disregard the above....

 - Gene

 p.s. anybody know what the -5v is used for on a PC motherboard? Can it
be left off for normal operation?

 ----------
From: List, Christopher
To: DIY
Subject: Switching power supply fry
Date: Friday, June 05, 1998 2:48PM

Hi guys -

I have a question regarding a switching power supply that came from an
external CD rom drive. As I was planning on using this inside my Akai
S3000XL to power an internal SCSI drive, this is on topic :).

While testing the setup, I accidently fired up the PS with the drive
attached, and the AC connections, - but not the ground :o

The PS died, but the drive and the sampler are OK. The PS has no power
at the +5v output and about 8v at the 12v output. I understand switching
supplies up to the FWR and the caps after it. The rest I haven't figured
out yet...
To speed the repair process I present this question; for a basic
switching supply like this (it is basic) what's the most likely thing to
have blown under these circumstances?

 - Thanks,
CList