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Power source system 1
Has the FUSE (F901)
blown?
PCB-INLET
PCB-POWER
PCB-MAIN
NO
YES
YES
Replace the lead wire.
Malfunction of PCB-MAIN.
NO
NO
YES
YES
YES
YES
NO
NO
LED does't illuminate.
Check the STBY5.
thermal protector : on the lamp box
Replace the PCB-
MAIN. Check that the
product enters the
stand-by mode.
Replace the PCB-
TERMINAL. Check that
the product enters the
stand-by mode.
Replace the PCB-
AUDIO. Check that the
product enters the
stand-by mode.
Replace the PCB-
PREAMP. Check that the
product enters the stand-
by mode.
IC950
: Primary side SW-IC
PC950
: Photo coupler for feedback
IC951
: Shunt regulator for feedback
Z954, Z955 : Circuit protector
Using the Terminal Shield as GND is allowed when checking the voltage waveform or terminal voltage on the secondary side.
NO
The product does not
enter the stand-by mode.
Check the failure on the PCB-
POWER, then replace the parts.
Is the thermal
protector
conducting?
Reset the thermal protector
and check the dust on the
filter.
Is the lead wire
to the RB
connector cut?
Is the pin No. 8
of the SF
connector 5V?
Remove the
SF connector
from the PCB-
MAIN.
Is the pin No. 9
of the RF
connector 5V?
Check the circuit around
IC950, IC951 and PC950,
then replace the parts.
Replace the PCB-
MAIN and check if the
product enters the
stand-by mode.
Malfunction of the PCB-MAIN.
Malfunction of the PCB-TERMINAL.
YES
YES
Malfunction of the PCB-AUDIO.
Malfunction of the PCB-PREAMP.
NO
NO
NO
NO
YES
YES
Malfunction of MEMBRANE
switch.
Replace MEMBRANE switch.
Malfunction of MEMBRANE
switch. Replace MEMBRANE
switch.
(Don't use a heat dissipation board as GND.)