Did you pull board(s) to do the electrolytics? Was it necessary to de-solder pins to get the power amplfier board into a position where you could work on it? Did you have to de-string the tuner?
I removed front panel (as far as it was possible without disconnecting absolute everything) and L profiles that hold cooler. It was necessary to free the pcb and have accesss to all the components. There is chassis profile under the front of the board so you can't access part there. De-soldering pins would be better, so board could come out completely so I didn't need to worry about broken wires, but I was lazy to do that. Note that 10uF/16V (4 pieces near the pots) are bipolars.
That left channel thing is mystery to me, don't know where to start. I don't believe those hard wires nor the trims. One bias trim came apart when I tried to regulate with it.