I need to figure out why it's dead, there are three fuses according to the schematic but I didn't spot them, so it looks like I have to disassemble further. Also there's a SCR in the power supply, I've never seen that before. Like a lot of audio electronics, the schematics are drawn with everything as a net, I can't quickly see where ground or power is, it's all lines among the signals.
Either it's a crowbar circuit (which was kind of common in big bench power supplies back then, never seen it in audio), or it controls the motor because of the timer function?