Troubleshooting - Toshiba D-VR7KC Service Manual

1 Power Supply Section
FLOW CHART NO.1
The power cannot be turned on.
Is the fuse normal?
Is normal state restored when once unplugged
power cord is plugged again after several seconds.
Is the AL+12V line voltage normal?
Check each rectifying circuit of secondary circuit
and replace P1 (BOARD MCV) if defective.
FLOW CHART NO.2
The fuse blows out.
Check the presence that the primary component
is leaking or shorted and replace P3 (BOARD
POWER SUPPLY) if defective.
After servicing, replace the fuse (F1001).
FLOW CHART NO.3
When the output voltage fluctuates.
Does the secondary side photo coupler circuit
operate normally?
Check the circuit and replace P3 (BOARD
POWER SUPPLY) if defective.
(IC1010, D1006, D1010, D1029)
FLOW CHART NO.4
When buzz sound can be heard in the vicinity of power circuit.
Check if there is short circuit on the rectifying diode and the circuit in each rectifying circuit of secondary side and
replace P1 (BOARD MCV) or P3 (BOARD POWER SUPPLY) if defective.
P1 (BOARD MCV) : IC2503, IC2504, IC5004, Q1055, Q1056, Q1057, Q1101, Q1102, Q1104
P3 (BOARD POWER SUPPLY) : D1012, D1013, D1014, D1015, D1016, D1018, D1021, D1022, D1023, D1034
FLOW CHART NO.5
AL-30V is not outputted.
Is the supply voltage of -30V fed to the anode of
D1018?
Check for load circuit short-circuiting or leak, and
replace P1 (BOARD MCV) if defective.

TROUBLESHOOTING

NOTE: BOARD MEANS PRINTED CIRCUIT BOARD.
Yes
Yes
Yes
Yes
Yes
No
See FLOW CHART No.2 <The fuse blows out.>
No
Check for lead or short-circuiting of primary
circuit component and replace P3 (BOARD
POWER SUPPLY) if defective.
No
(Q1001, Q1003, Q1008, T1001, D1001, D1002,
D1003, D1004, D1011, D1028, C1003, C1035,
C1036)
Check the presence that the rectifying diode or circuit
is shorted in each rectifying circuit of secondary side
and replace P1 (BOARD MCV) if defective.
Check the circuit and replace P3 (BOARD POWER
No
SUPPLY) if defective.
(IC1010, Q1031, D1017, D1025, D1036)
No
Check D1018 and their periphery, and replace
P3 (BOARD POWER SUPPLY) if defective.
1-10-1 E9KG0TR