Alpine 3542 no sound

[Perry Babin]

For op-amps in a circuit that uses local feedback (this circuit), the output and inverting input of each op-amp section should closely match the non-inverting input.

That's essentially what you have.

The voltage that you saw change with the gain selector change is due to a change in local feedback.

Without a scope, it's difficult to know for certain whether the amp is 100% healthy. It likely is if it sounds OK, especially with the numbers you last posted.

 

[DeHchik]

It remains only to find a replacement for Q318 - 2SB1076M, instead of it there is still TIP107. Thank you very much Perry for your help and health during this difficult time.

 

[Perry Babin]

Did your tester see the TIP107 as good and the original as bad?

 

[DeHchik]

Did your tester see the TIP107 as good and the original as bad?

Yes.

 

[Perry Babin]

Without Q319 in the circuit, does the amp produce audio? If so, I'd try virtually any transistor with a pin configuration that will match. Higher hfe is better but it's may not be that critical.

 

[DeHchik]

Yes, without Q319 in the circuit, the amplifier reproduces sound. I'll try to find a suitable transistor. Thanks for the help with the repair.