Denon DVD-900 Service Manual page 4

FLOW CHART NO.4
When the output voltage fluctuates.
Does the photo coupler circuit on the secondary
side operate normally?
Does the photo coupler circuit on the primary side
operate normally?
FLOW CHART NO.5
When buzz sound can be heard in the vicinity of the power circuit.
Check if there is any short-circuit on the rectifying diode and the circuit in each rectifying circuit of the secondary side.
(D1003, D1008, D1009, D1013, D1016, D1030, IC1002, Q1002, Q1004, Q1007, Q1011, Q1014)
FLOW CHART NO.6
The fluorescent display tube does not light.
Is the voltage of 5V supplied to Pins(6, 24)
of IC2001?
Is the voltage of -24V supplied to Pin(15) of
IC2001?
Is there 500kHz oscillation to Pin(26) of IC2001?
Check the signal lines of FP-DIN, FP-DOUT,
FP-CLK, FP-STB of IC2001 and CN1001?
Are the filament voltage applied between (1, 2)
and (34, 35) of the fluorescent display tube?
Also negative voltage applied between these pins
and GND?
Replace the fluorescent display tube.
FLOW CHART NO.7
The key operation is not functioning.
Are the contact point and the installation state of the
key switches(SW2204-2210, 2901-2907) normal?
Is the control voltage normally supplied to
Pins(3, 4, 7, 8, 9, 10, 11, 12, 13, 14) of IC2001?
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Check the circuit and replace the parts.
(IC1001, IC1006, D1048, D1015)
No
Check the circuit and replace the parts.
(IC1001, D1020, D1024)
No
Check the EV 5V line.
No
Check the -FL (-24V) line.
No
Check R2001, IC2001 and their periphery.
No
Check or replace IC2001 and DVD Main CBA unit.
No
Check or replace the power circuit, D1016, D1017
and R1042, and their periphery.
No
Check the key switches (SW2204-2210,
2901-2907), and their periphery circuit.
- 4 -