NO
YES
12V on the
preamp relayis correct?
NO
Check Q990 Q991
Check D990 D991
YES
A
+72V
power supply is correct?
Check R646 R647 R746 R747 R622
Check B606 B706
Check Q609 Q610 Q611
Check the PCB track
THE END
YES
-72V
power supply is correct?
NO
Check R623
Check Q612 Q613
3-3