Denon AVR-1712, Service Manual

Page: 62 / 161

62
4.2. Power AMP (MAIN UNIT)
No sound is output.
The protector operates.
Is the power transistor open or short-
circuited?
2SB1560/2SD2390
Is the emitter resistance of the power
transistor open?
0.47Ω
Is the base resistance of the power
transistor open?
22Ω
Is the trimmer potentiometer between the
base of the power transistor open?
1kΩ
Are the zener diode and diode which
are connected with the base of a power
transistor short-circuited?
MTZJ3.3B
1SS133
Is other transistor trouble?
Is other resistance trouble?
Turn on the power, check that voltage of the section is normal and that idling electric current is
flowing.
Replace the power transistor.
Replace the transistor.
Replace the resistance.
Replace the emitter resistance.
Replace the base resistance.
Replace the trimmer potentiometers.
Replace the zener diode and the diode.
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
YES