Here's what's happening:
At startup, RL2 instantly closes. However, RL1 never does. So I have full preamp/control functionality, but there is NO 55V voltage in the system. RL1 never energizes, there is 0V across its terminals, traceable back to the "delayed start" circuitry on Module 6. I get lost there, though. The capacitor is new, and all else looks visually OK.
Is this circuitry part of the "protection" system? (The "clipping" light never comes on at all.) I did pull and test the output transistors; B-C and B-E were OK, but C-E were shorted. Would this cause the +/-55V rail to shut off?
How much would it cost to get those transistors (TIP141/146 x3) from you?
I read, in another thread, you guessed (correctly) that a trimmer pot shorted, and took out the emitter resistors and output transistors. This appears to be exactly what happened in my unit. I have replaced the trim pots (on both output boards) with 10-turn Bourns type, but I am very frustrated that I can't get the 55V to the board to properly set the bias voltage!
Thanks for sharing your knowledge!
Jeff