Analog Audio - Marantz SR7013 Service Manual

4.2. Power AMP (AMP PCB)
When using the protection pass mode, do not connect speakers to the speaker terminals.
No audio output.
Protection is activated.
YES
Is the power transistor open or short circuited?
2SB1647 / 2SD2560
NO
Is the emitter resistor of the power transistor
open?
0.47 Ω
NO
Is the base resistor of the power transistor open?
22 Ω
NO
Is the trimmer potentiometer between the base of
the power transistor open?
1 k Ω
NO
Are any other transistors faulty?
NO
Are any other resistors faulty?
NO
Turn on the power and, check that the voltage of each part is correct and that there is an idling current.
YES
Replace the power transistor.
YES
Replace the emitter resistor.
YES
Replace the base resistor.
YES
Replace the trimmer potentiometers.
YES
Replace the transistor.
YES
Replace the resistor.

4.3. Analog audio

No audio output.
Is a voltage of ± 7V supplied to INPUT PCB [BN64]?
YES
Is there an audio signal in INPUT PCB [BN461,
BN462]?
NO
Is the connector correctly connected to the DIGI-
TAL PCB?
YES
Reconnect the connectors correctly.
If the malfunctioning channel and function can be identified, check the corresponding signal path.
94
NO
Repair the ± 7V power supply.
YES
Repair the power amplifier.
NO
Connect the connectors correctly.
YES
Repair the DIGITAL PCB.