Electronics > Repair
Yamaha RX-V765 Amplifier Issue
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irobot:
Yamaha RX-V765 7.1 Channel Home Theater Receiver
After replacing Q1055A and Q1055C (outputs) and emitter resistor R1153:
-1.5V DC on speaker output, SL channel. Although the unit works, it should be near zero. Not comfortable leaving it this way.
B+ and B- are where they should be at all points.
I'm at a loss because I've checked every component and taken other measurements using good channels as reference.
Voltages on other channels are just about spot on to what schema shows.
I replaced Q1041, Q1048, C1034 with no change.
Notes: Q1020, Q1027, Q1034 are for bias. Q1062 is a tap-off point for protect signal. Q1027 is physically attached to heatsink as temperature "sensor".
UPDATE 10/04/2024: Fixed. Replaced Q1011 and Q1012. Although checked out OK in and out of circuit, these must have been breaking down with power applied.
David_AVD:
There will likely be a dead transistor or resistor somewhere just before the output transistors.
suntime:
Hi,
Check Q1020 & Q1011.
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