Well, if the relay is engaging, it is most likely your power amplifiers are fine. Confirm after the relay clicks, measure DC offset at the speaker terminals (with the speaker switch actuated of course)- volume down. It should be 0-30mV or so. I want you to first check all the basics, tape monitor 2 switch is off and the speakers A or B are selected according to the switch and the rear terminals you are using. Select aux and feed a signal in, turn up the volume a bit. Just to get the obvious out of the way. If it is still dead, check the +/-32v rails at the emitters of Q29 and Q28 as they supply the low level EQ amp and the tone/flat preamps.