Soundsystem - Amp2 Help

[BAC1]

Hi
Is there anyone out there who has experience repairing the AMP2 in the ICM3 stereo sound system?
Trying to get a circuit diagram or some help to localize the problem!!

And the probem is - It's dead. Red optosignal comes in to the unit and I get a transmit red signal for 15 sec. Then it will turn black.
Of course, I have no sound and no image on the screen.
I have 12V power in the socket.

And I purchased another unit ( second hand ) that worked for 2 weeks(!) That unit is complete dead with no red signal transmitted.

I need help! Thank You!

[BAC1]

This AMP2 was ( also ) dead after a battery change.
(I have read at least two post with the same issue now )