Denon DVD-1720/556 Service Manual page 21

FLOW CHART NO.14
The disc tray cannot be opened and closed. (It can be done using the remote control unit.)
Is the normal control voltage inputted to Pin(4) of
IC2001? Refer to "FLOW CHART NO.12" <The key
operation is not functioning.>
Refer to "FLOW CHART NO.15" <The disc tray
cannot be opened and closed.>
FLOW CHART NO.15
The disc tray cannot be opened and closed.
Replace the DVD Main CBA Unit.
No improvement can be found.
Replace the DVD Mechanism.
FLOW CHART NO.16
[No Disc] indicated. (When the focus error occurs.)
Replace the DVD Main CBA Unit.
No improvement can be found.
Replace the DVD Mechanism.
FLOW CHART NO.17
[No Disc] indicated. (When the focus servo is not functioning.)
Replace the DVD Main CBA Unit.
No improvement can be found.
Replace the DVD Mechanism.
FLOW CHART NO.18
[No Disc] indicated. (When the laser beam does not light up.)
Replace the DVD Main CBA Unit.
No improvement can be found.
Replace the DVD Mechanism.
Yes
Yes
Yes
Yes
Yes
No
Replace the "OPEN/CLOSE" button (SW2108).
No
Original DVD Main CBA Unit is poor.
No
Original DVD Main CBA Unit is poor.
No
Original DVD Main CBA Unit is poor.
No
Original DVD Main CBA Unit is poor.
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DVD-1720/556