"Tweetldee" wrote:

First, tell us how much you know about electronics and
troubleshooting
electronic circuits.

I got an education in communication electronics where I got the basics
in electronic.
Most of the the time we worked on microcontrollers. Unfortunately I
just got a little theory in analog devices, like audio amps, so I would
be very pleased if someone could give me some hints.

If the answer to both questions is "nothing" or "very
little", then the best course of action for you, to minimize the
repair
expense, is to take the unit to a repair shop and have them look it
over.
If you have no electronics training or experience, then you risk
causing
much more damage than the amp already has.

I think I can do it with a little guiding...

To get a more direct response, you should always post the make and
model
number of any equipment or component for which you're seeking
information or
help.

It's the SONY TA-AV501R.
Perhaps I can put the schematics of the power board on an ftp-site if
this would help.

Cheers!!!

Cheers,too!
arvid