"Dan K" wrote in message
. ..

"Arfa Daily" wrote in message
news

"Mark D. Zacharias" wrote in message
. com...
Arfa Daily wrote:
"Mark D. Zacharias" wrote in message
et...
I powered the amp back on and it worked. The only difference
being I was running without a heat sink now.


Perhaps the output transistors weren't insulated from the heat sink?

Mark Z.

That was my first thought also, Mark, but if you go up 4 posts, you
will see that he makes a point of saying that he checked that the
devices were isolated from the heatsink. It's a mystery ... |:-{

Arfa

Could have a damaged insulator...

mz


Could be. Might just be the way we are interpreting " checked ". When I
check that devices are isolated from a heatsink, I prove it with a meter
reading. Perhaps he was just visually inspecting ...

Arfa

Nope, meter reading. Isolated. It wouldn't have worked for a while if
they wasn't isolated, Vee would be shorted to Vcc. Could always be a
crack in the insulator I suppose that only shorts at certain times...They
look ok though

Dan

Yeah, it kinda sounded like you had a done a proper test when I first read
it, and you are of course right that it wouldn't have worked ok for a
while - I'd forgotten that bit ...

Arfa