Troubleshooting - Denon DVD-900 Service Manual

FLOW CHART NO.1
The power cannot be turned on.(1)
Is the fuse normal?
Is normal state restored when once unplugged
power cord is plugged again after several seconds?
Is the EV 5V line voltage normal?
Is the voltage of secondary side normal?
FLOW CHART NO.2
The power cannot be turned on.(2)
Does the change from STANDBY LED indicate
turn-off?
Is the voltage of 3.3V supplied to Q2021?
Is the "H" signal inputted to the base of Q2021,
when the POWER button activated on the DVD?
Is the "H" signal inputted at base of Q2021,
when the POWER button activated on the remote
control unit?
Replace Q2021.
The STANDBY LED indicate is flashing after 0.5 sec.
Are the "P-ON-H" pulse outputted from the
pin(20) of CN1001?
Is the P-CON switch circuit operated normally?
(Q1002, Q1005, Q1006, IC1002, D1036, D1046)
FLOW CHART NO.3
The fuse blows out.
Check the presence that the primary component
is leaking or short then service it if defective.
After servicing, replace the fuse.

TROUBLESHOOTING

Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes (below, confirmed operating at LED turn-off of 0.5 sec. interval.)
Yes
No
See FLOW CHART No.3 <The fuse blows out.>
Check if there is any leak or shor-circuit on the
No
primary circuit component?
(Q1001, Q1003,T1001, D1001, D1002, D1004,
No
D1005, D1011, C1003, C1005)
No
Check each rectifying circuit of secondary circuit.
No
No
Check the EV 3.3V line.
No
Check the POWER button line.
No
Check the line between the remote control
receiver and Pin(26) of CN1001.
Replace the DVD Main CBA Unit.
No
No
Check each component, and replace.
Check the presence that the rectifying diode or
circuit is shorted in each rectifying circuit of
secondary side then service it if defective.
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