Denon AVR-791 Service Manual

44
4.2. Power AMP (7CH AMP B'D)
No sound is output.
The protector operates.
Is the power transistor open or short circuit?
2SB1560/2SD2390
Is the emitter resistance of the power
transistor open?
0.47Ω
Is the base resistance of the power
transistor open?
22Ω
Is trimmer potentiometer between the base
of the power transistor open?
1kΩ
Is 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 power, check that voltage of the section is normal and that idling electric current is owing.
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
YES

Denon AVR-791 Specifications

General

Number of Channels	7.1
HDMI Inputs	4
HDMI Outputs	1
Audyssey Technologies	Audyssey MultEQ, Audyssey Dynamic Volume, Audyssey Dynamic EQ
4K Pass-Through	No
Signal-To-Noise Ratio	100 dB
HDMI Switching	Yes
Input Sensitivity	200 mV
THD	0.08%
Surround Sound Effects	Yes
Digital Sound Processor (DSP)	Yes
DSP Preset Qty	7
Tuner Bands	AM/FM
Preset Station Qty	56
Auto Preset Memory	Yes
HDMI Pass-Through	Yes
Frequency Response	10Hz-100kHz
Power Output	90 W per channel (8 ohms, 20Hz-20kHz, 0.08% THD)
Dolby Technologies	Dolby Digital Plus, Dolby TrueHD
DTS Technologies	DTS, DTS-HD Master Audio, DTS-HD High Resolution Audio, DTS Neo:6
Response Bandwidth	10 - 100000 Hz
Input Impedance	47 kΩ
Audio D/A Converter	24-bit / 192kHz
DSP Presets	Rock Arena, Jazz Club, Mono Movie, Matrix, Virtual, Game
Tuning Range	AM: 520 - 1710 kHz, FM: 87.5 - 108 MHz
Connector Type	HDMI
Amplifier Output Details	90W x 7 (8 ohms, 20Hz-20kHz, 0.08% THD)
Video Conversion	Yes (Composite to HDMI)