"Arfa Daily" wrote in message
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"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