I have a 7070 receiver that did the classic worked when turned off, won't turn back on. I've read through several threads about similar problems and have replaced all of the fuseable resistors on board F-2624. Still no relay click on turn on. I can set the bias on both channels but cannot adjust the DC output voltage on either channel which is 4.3 volts. If I pull board f-2624 and turn the unit on, no click. If I pull both F-2624 and F-2626 and turn the unit on, the relay clicks. Ideas?