[Jack[_11_]]

Dave Platt wrote:
In article , Jack wrote:

Given the behavior described above I can only guess that a rise in
voltage in the main amp produced by turning up the volume with the
speakers turned off somehow corrects the condition causing this problem,
but at the moment I don't know what this condition might be.

One thing to suspect in cases like this, is a bad electrolytic
coupling capacitor between one stage and the next.

Bad output-protection relays can also cause this sort of "turn it up
far enough and it starts working" problem.

Usual next step is to use a signal tracer / oscilloscope, and see how
far through the output circuitry you can detect audio when it's in the
"not working" condition.

I just bridged the left channel contacts on the relay and got nothing,
so the problem appears not to be with the relay itself. There is a
circuit on the schematics called the "Protection Circuit Assembly", the
sole purpose of which appears to me to be to activate the relay. Seeing
as how the relay activates I don't see that as being the source of the
proble so I will proceed to the left channel of the main amp section.