Protection Board voltages, second report . . . Those all look ok: pins 4 and 5 are right channel, difference of 84 mVdc (0.084 Vdc); pins 6 and 7 are left channel, difference of 5mVdc (0.005 Vdc) If the protection relay is not pulled in you may have two problems, the bias adjustment failure and a protection board fault. What are the dc voltages on the cathodes of D6, D7 and D8, and the emitter, base and collector of Q5 on the protection board? Sorry Watthour, but your decimal point is off, silicon pn junction is about 600mV to forward bias (0.600 vdc not 0.065 vdc) I know you know . . .