Yamaha RX-A760, Service Manual

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36
RX-V681/RX-A760
RX-V681/RX-A7
60
2-2. When the protection function worked due to abnormal DC output.
Cause: DC output of the power amplifier is abnormal.
Supplementary information:
The protection function worked due to a DC voltage appearing at the speaker terminal. A
cause could be a defect in the amplifier.
Turning on the power without correcting the abnormality will cause the protection function to work in
5 seconds and the
power supply will be shut off.
2-3. When the protection function worked due to abnormal voltage in the power supply section.
Cause: The voltage in the power supply section is abnormal.
Supplementary information: The protection function worked due to a defect or overload in the power supply.
Turning on the power without correcting the abnormality will cause the protection function to work in 1 second and the
power supply will be shut off.
Notes:
• Applying the power to this unit without correcting the abnormality can be dangerous and cause additional
circuit damage. To avoid this, if
“
PS
”
and
“
DC
”
protection function works 3 times consecutively, the power will
not turn on even when the
“
MAIN ZONE z
”
key is pressed. In order to turn on the power again, start up the
selfdiagnostic function.
• The output transistors in each amplifier channel should be checked for damage before applying power to this
unit.
• Amplifier current should be monitored by measuring DC voltage across the emitter resistors for each channel.
PS PRT:xxx
xxx: A/D conversion value of voltage at the moment when the protection function worked
(Reference voltage: 3.3 V=255)
PS1/PS2/PS3
DC PRT:xxx
xxx: A/D conversion value of voltage at the moment when the protection function worked
(Reference voltage: 3.3 V=255)