Denon DCD-520AE, Service Manual

Page: 41 / 104

41
Is +3.3V_D2. voltage supplied to Pins(37) of F701?
Is the voltage of approxi42V supplied to Pin(38) of F701?
The luorescent display tube does not light up.
Is the voltage of approxi6V supplied to
Pin(1),(43) of F701?
Check the luorescent display tube control signal of ab microcomputer.
(VFD_RSTI,VFD_CE,VFD_CLK,VFD_DI)
+42V is not outputted.
The key operation is not functioning.
Check if there is any leak or short-circuit on the loaded circuit, and
service it if defective.
When pressing each switches (S701-706), do the voltage of pin
(91),(92) of IC11 decrease?
Is approxi42V voltage supplied to the kathode of D973?
Are the contact point and the installation state of the key switches
(S701-706) normal?
Replace IC11.
Check the +3.3V_D2. line and service it if defective.
Check the +42V line and service it if defective.
NO
NO
Check the FL1/FL2 line and service it if defective.
Check D973, D974, Q971 and periphery circuit, and
service it if defective.
Re-install the switches (S701-706) correctly or replace
the poor switch.
Check the switches (S701-706) and their periphery, and
service it if detective.
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
FLOW CHART NO.3
FLOW CHART NO.4
FLOW CHART NO.5