Maintenance And Inspection; Troubleshooting; Power Supply Section - Hitachi DV-PF73U Service Manual

3

MAINTENANCE AND INSPECTION

3-1 TROUBLESHOOTING

Troubleshooting is how to service for the specifying malfunction or poor parts.
Detect malfunction or poor parts and service as the following charts.

3-1-1 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+5V line voltage normal?
Check each rectifying circuit of secondary circuit
and service it if defective.
FLOW CHART NO.2
The fuse blows out.
Check the presence that the primary component
is leaking or shorted and service it if defective.
After servicing, replace the fuse.
FLOW CHART NO.3
When the output voltage fluctuates.
Does the secondary side photo coupler circuit
operate normally?
Check the circuit and service it if defective.
(IC1001, D1012, D1024)
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
service it if defective. (D013,D015,D016,D1008,D1010,D1016,D1020,IC1002,IC1004,Q055,Q056,Q057,Q1004,Q1006,Q1011)
FLOW CHART NO.5
-FL is not outputted.
Is the supply voltage of -24V fed to the anode of
D1010?
Check for load circuit short-circuiting or leak, and
service it if defective.
Yes
Yes
Yes
Yes
Yes
No
See FLOW CHART No.2 <The fuse blows out.>
No
Check for lead or shor-circuiting of primary
circuit component and service it if defective.
(Q1001,Q1003,T1001,D1001,D1002,D1003,
No
D1004,D1011,C1003,C1005)
Check the presence that the rectifying diode or circuit
is shorted in each rectifying circuit of secondary side
and service it if defective.
Check the circuit and service it if defective.
No
(IC1001, IC1006, D1018)
No
Check D1010 and their periphery, and service it if
defective.
3-1