Mitsubishi SL1U Service Manual page 36

Power source system 3
Abnormal power source for SW
(SW3.3, SW15.5, SW5A, SW9AU)
Are RD-SD, RF-SF,
RN-GN and GV-SV
lead wires OK?
YES
Remove the PCB-MAIN
and connect the PCB-
POWER TEST.
Is the abnormality
caused by SW3.3
error?
NO
Is the abnormality
caused by
SW15.5 error?
NO
Is the abnormality
caused by SW5A
error?
NO
SW9AU power source
abnormality
Is the voltage of
pin the No. 2 of the
SV connector 9V?
PCB-MAIN
YES
Malfunction of the
PCB-MAIN.
Malfunction of IC3A1 or
short circuit around IC3A1.
NO
Turn on FAN and POWER
on the PCB-POWER TEST.
Is the voltage of
the pin No. 6 of
YES
the RF connector
3.3V?
YES
Is the voltage of
the pin No. 4 of
YES
the RD connector
15.5V?
YES
Is the voltage of
the pin No. 2 of
YES
the RD connector
5V?
YES
Remove the SV
connector from
NO
the PCB-MAIN.
NO
NO
PCB-POWER
NO
PCB-POWER
NO
PCB-POWER
Is the voltage
of the pin No. 2
of the GV
connector 9V?
PCB-AUDIO
NO
Remove the GN
connector form
the PCB-AUDIO.
Is the voltage
of the pin No.
2 of the RN
connector 9V?
PCB-POWER
- 4 -
Insert the lead wire.
Malfunction of IC953 or short
circuit around IC953.
Malfunction of Z950, Z951
or IC904, or short circuit
around them.
Malfunction of Z950, Z951
or IC906, or short circuit
around them.
Malfunction of the
YES
PCB-MAIN.
Malfunction of the
YES
PCB-AUDIO.