weird Hitachi amplifier problem

[mikefc55]

I've got a real head scratcher on the bench right now. The left channel is nothing more than a unity gain amp, the right channel is fine. The output volume is clean and ramps up and down on the left side but only equals the pre amp output. If you cheat the balance knob you can get a balanced output. I have pulled most of the transistors and they are fine. DC voltages seem fine and generally match the schematic and the right side. My thought is if an active component can ramp up and down with a low value input it's good, it just needs a bigger Vcc to attain gain. All +/- Vcc are good. even the collector voltages on the o/p transistors are correct.Can anyone offer any idea of what would cause an amp to do this? At this point I'm just looking for where to look next. I'd rather not upload the diagram and ask you to fix it for me. Thanks

BTW: I thought I had it when I noticed a weird perf board circuit taking the o/p across the right side load resistor and feeding it back to the protect board. It's only on the right but removing it does nothing.

 

[ramussons]

Nothing much can be said without the circuit diagram.

 

[shrtrnd]

ramussons has a point.
My basic input is to do the obvious checks first before getting into the weeds of the circuitry:
1) Did you swap speakers to ensure the speaker or the connections to the speaker are good.
2) Did you check the volume potentiometer for problems. (and it's connections)
I admit it sounds like a circuit problem, but without a schematic, I'd check the obvious first.