Troubleshooting - Denon DVD-1720/556 Service Manual

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 EV +3.3V line voltage normal?
Check each rectifying circuit of the 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 photo coupler circuit on the secondary
side operate normally?
Check IC1001, D1012, D1024 and their periphery,
and service it if defective.
FLOW CHART NO.4
When buzz sound can be heard in the vicinity of power circuit.
Check if there is any short-circuit on the rectifying diode and the circuit in each rectifying circuit of the secondary
side, and service it if defective. (D1003, D1006, D1008, D1016, D1030, IC1002, Q1002, Q1004, Q1005, Q1011, Q1014)
FLOW CHART NO.5
-FL is not outputted.
Is approximately -23V voltage supplied to the
anode of D1003?
Check if there is any leak or short-circuit
on the loaded circuit, and service it if defective.

TROUBLESHOOTING

Yes
Yes
Yes
Yes
Yes
No
See FLOW CHART No.2 <The fuse blows out.>
No
Check if there is any leak or short-circuiting on the
primary circuit component, and service it if defective.
(Q1031, Q1003, Q1008, T1001, D1001, D1002,
No
D1004, D1005, 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.
No
Check IC1001, IC1006, D1048 and their
periphery, and service it if defective.
Check D1003 and periphery circuit, and service it
No
if defective.
18
DVD-1720/556