[ben]

While you're in there, check the soldering on the output sockets. I have worked on dozens of these and in most of them there were cracked joints.

The no audio problem that resolved itself rings a bell, I think I had one with a capacitor in the amp that had turned into a resistor and muted the audio. Will see if I made a note. Oddly enough the rec-pb sliders rarely gave trouble in my experience.

Another thing to check is the condition of the belt. Ensure there is no slipping when you put the deck into record as well as play - a loose belt will not manage to drive the flywheel under load, or will do so intermittently. Likewise, there should be full auto shut off in all transport modes - if it doesn't happen, new belts are needed.