Read Sharp LC-37GE1E (serv.man7) Service Manual online
LC-37GE1E
7 – 22
Backlight failure to light up
Do all the fluorescent tubes light up?
NO
Check the individual fluorescent
tubes for light-up failure.
tubes for light-up failure.
YES
Replace any defective fluorescent
tube (s) with new one (s).
tube (s) with new one (s).
Is the power supplied to CN7501 on
the inverter unit?
the inverter unit?
NO
Check the connection between power
unit and inverter unit.
unit and inverter unit.
YES
Iis the F7501 fuse in the inverter unit
circuit functioning?
circuit functioning?
NO
Replace the blown-out F7501 fuse on
the inverter unit. Turn on the power
again.
If the fuse gets blown out again,
check the short-circuited spot.
the inverter unit. Turn on the power
again.
If the fuse gets blown out again,
check the short-circuited spot.
YES
Check T7501 and T7502 and their
peripheral circuits as well as IC7501
and their peripheral circuits.
peripheral circuits as well as IC7501
and their peripheral circuits.
YES
Is the VCC power supplied to the
control IC (IC7501) on the inverter
unit?
control IC (IC7501) on the inverter
unit?
NO
Check the circuit connected with the
VCC terminal on the inverter control
IC (IC7501).
VCC terminal on the inverter control
IC (IC7501).
YES
Has each control signal come to
CN7502?
(INV-OFL,INV-OSC,INV-STB,INV-
BRT)
CN7502?
(INV-OFL,INV-OSC,INV-STB,INV-
BRT)
NO
Have INV-OFL/OSC and the INV-STB
signal come to P1701(LB) in the
MAIN substrate?
signal come to P1701(LB) in the
MAIN substrate?
NO
Check pins (19),(17) and (89) of
IC1710 (main PWB) .
IC1710 (main PWB) .
YES
Is the specified control signal input-
ted at IC7501 (INV-CTL) on the
inverter unit.
ted at IC7501 (INV-CTL) on the
inverter unit.
NO
Check the line between CN7502 and
IC7501.
IC7501.
YES
Are the Q7501 and Q7502 transis-
ters at the primary side of T7501
functioning?
ters at the primary side of T7501
functioning?
NO
Check the power line of IC7501,its
peripheral circuits or replace IC7501.
peripheral circuits or replace IC7501.
YES
Is the secondary circuit of T7501
functioning.
functioning.
NO
Replace T7501 or the T75** trans-
former for the fluorescent tubes, or
check their peripheral circuits.
former for the fluorescent tubes, or
check their peripheral circuits.
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