Read Sharp LC-32D44E (serv.man5) Service Manual online
LC-32D44E/S/RU-BK/GY
4 – 2
The backlight does not light
Are all fluorescent lamps on?
NO
Check each fluorescent lamp, and replace if defective.
(CN7503-12, etc.)
(CN7503-12, etc.)
NO
Is F7501 normal?
NO
Check if the peripheral circuits are short-circuited or parts are faulty.
(Q7501, Q7503, etc.)
(Q7501, Q7503, etc.)
YES
Is 60V applied to both ends of C7501?
NO
Refer to "No power supply (Front LED does not light up)" and "No
power-up even if turned on (Front LED light up)".
power-up even if turned on (Front LED light up)".
YES
Is a voltage of 13V applied to PIN(20) of IC7501?
NO
Check the 13V line and the peripheral circuits.
YES
Is the STB_ON/OFF signal supplied from PIN(2) of
CN7502?
CN7502?
NO
Check the STB signal line on the MAIN_UNIT side and the peripheral
circuits.
(P2303/CN7502, etc.)
circuits.
(P2303/CN7502, etc.)
YES
Is each control signal of connector CN7502 normally func-
tion?
tion?
NO
Check each control circuit.
PIN(3) OFL (PWM light control signal input)
OFL (PWM light control signal input)/H: Lamp ON, L: Lamp OFF
PIN(5) ERR (Error output)
ERR (Error output)/H: Normal, L: Error
PIN(7) REG2 (Light control method identification)
REG2 (Light control method identification)/H: External PWM input, L:
Analog voltage input
Analog voltage input
PIN(9) ADIM (Tube current setting)
ADIM (Tube current setting)/H: Tube current 12mA, L: Tube current
8.5mA
8.5mA
YES
Is [0] displayed as the number of [LAMP_ERROR] in the
process mode?
process mode?
NO
Reset the number of [LAMP_ERROR] to the default value in the pro-
cess mode.
cess mode.
YES
Is the drive output signal sent from PIN(16) and (15) of
IC7501?
IC7501?
NO
Check IC7501and the peripheral circuits.
YES
Does the drive output circuit normally work?
NO
Are Q7509-10, Q7501-4, etc. faulty? Check the peripheral circuits.
YES
Does the secondary side of T7501-5 normally work?
NO
Is T7501-5, etc. faulty? Check the peripheral circuits.
YES
Check if the feedback circuit is normal.
(D7501-5, D7507-11, D7513-17, etc.)
(D7501-5, D7507-11, D7513-17, etc.)
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