[Tim Schwartz]

wrote:
I've got an older Technics amp (no tuner) that gets crackly on both
channels after it runs about 30 minutes or so. Sounds fine when you
start it up. Switches and pots have all been cleaned. Any
suggestions? I'm guessing power supply but not sure what it could
be. Do the big caps start leaking after they get hot?

James,

While I don't disagree with the other posters, look to see if your unit
uses an STK IC driver module, something like an STK-3042 or an STK-3076,
among dozens of different numbers and variations. I have certainly seen
this series of IC's, especially if the design does not include a heat
sink go bad in the way you describe. It could also be an output IC,
especially a stereo one, since its effecting both channels. You might
try looking at the soldering on the IC's, or hitting them with some
freeze mist once the crackling starts.

Of course, your amp might not use them at all, which would make my post
sort of useless. If you put out another posting, please include the
model of your amp.

Regards,
Tim Schwartz
Bristol Electronics