23 Sep
2008
23 Sep
'08
4:55 p.m.
Re: "For the record, the time I did it was in a DEC H754 -15V regulator
brick (which is, of course, a switcher). I had it on dummy load, so I knew
it wasn't really being asked to supply too much current, but there was no
output. I lifted the collector lead of the current sense transistor and
switched on. BAD MISTAKE!. The crowbar was firing (incorrectly, the zenner
diode had failed), so there genuinely was an overcurrent situation. The
result was that 4 of 5 transistors fialed (some were blown apart), the
current sense resisitor burnt out (I think it actually glowed) and the fuse
blew."
Isn't it amazing how nasty electricity can get once you get it pissed off?