Amp Adjustment; Confirmation Of Idling Current - Yamaha R-S300 Service Manual

R-S300

■ AMP ADJUSTMENT

● CONFIRMATION OF IDLING CURRENT
1. Right after power is turned on, confirm that the voltage across the terminals of R154 (L ch) and R155 (R ch) are
between 0.1 mV and 10 mV.
2. If measured voltage exceeds 10 mV, open (cut off) R139 (L ch), R140 (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)
R154
30
0.1mV–10mV
(R ch)
R155
MAIN (1) P.C.B.
R139 (L ch)
R140 (R ch)
R140
R155
R154
R139
Cut off