Before I start, we REALLY need to know what you want to do with this! Are you going to try to use the built-in amps to feed multiple speakers directly? Are you just looking for a line output to feed to a system you're building? The lack of specificity in your questions would make responses HUGE.

I posted here a few minutes ago, then looked at the manual. Most of my comments are new.

Five minutes later: all writing cancelled. I just erased a dozen paragraphs.

P 139 seems to show what you need.

I'll be glad to consult on other details of this beast if you like. I installed a similar unit, a Wurlitzer 50-LP changer... in 1988 or so. I have some idea of the audio approaches here. Squirrely. But look at page 139.