Trouble Shooting; Flow Chart No.1; Flow Chart No.2 - Denon DCD-720AE Service Manual

TROUBLE SHOOTING

FLOW CHART NO.1

The power cannot be turned on.
Is Power LED lit?
YES
Is the MCU +3.9V line voltage normal?
YES
Is normal state restored when once unplugged power cord is plugged
again after several seconds?
YES
Is the USB+5V line voltage normal?
YES
Check each voltage regulator circuit and service it if defective.

FLOW CHART NO.2

D+3.3V is not outputted.
Is USB+5V voltage supplied to Pin(3) of IC22?
YES
Check IC22 and the periphery circuit, and service it if defective.
NO
Check if there is any leak or short-circuiting rectiier
circuit of SUB Power transformer, and service it if
defective.
NO
(T901,D903,D904,D905,D906,IC91,Q904,Q905)
NO
Check if there is any leak or short-circuiting on rectiier
circuit of MAIN Power transformer, and service it if
defective.
(MAIN TRANS,D951,IC51)
NO
NO
Check IC51 and the periphery circuit, and service it if
defective.
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