Power Amplifier Adjustment; Confirmation Of Idling Current - Yamaha A-S701 Service Manual

A-S701

■ POWER AMPLIFIER ADJUSTMENT

● CONFIRMATION OF IDLING CURRENT
1. Right after power is turned on, confirm that the voltage across the terminals of R156-R159 (L ch) and R157-R158
(R ch) are between 0.1 mV and 10 mV.
2. If measured voltage exceeds 10 mV, open (cut off) R139 (L ch), R142 (R ch) and reconfirm the voltage.
Attention
If the measured voltage exceeds 10 mV after repairing the power amplifier, check other parts again for any possible
defect before cutting the resistor.
3. Confirm that the voltage is between 0.2 mV and 15 mV after 60 minutes.
0.1mV–10mV
(L ch)
R159
26
R156
0.1mV–10mV
(R ch)
R157
MAIN (1) P.C.B.
R156
R139
R159
R139 (L ch)
R158
R142 (R ch)
R158
R142
R157
Cut off