[Ron Ramirez]

It's official - the problem must be the power-speaker switch.

I disconnected the wires from terminals H1 and H2 that go from the receiver outputs to the speaker switch. I also disconnected the wires running to the left and right "main" speaker terminals.

In their place, I ran two wires direct from H1 and H2 to the "main" speaker terminals.

I turned the unit on and...no distortion.

I sat and listened to it for five or ten minutes, and it did well the entire time.

So now I can try and pull the switch for a deep cleaning, or just leave the wires in place. Of course, I will try to remove the switch as I will not be satisfied with a rigged-up solution. I would prefer to be able to switch between main or remote speakers or headphones as per original.