Sharp LC-32GD8EE Service Manual page 56

LC-26GA5E
LC-32/37GD8E/RU
LC-32GA5E
LC-32/37BT8E/RU LC-32/37GD8E/RU
LC-32/37BT8E/RU
Troubleshooting Table (continued)
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Do all the fluorescent tubes light up?
YES
Is the power supplied to CN7501 on
the inverter unit?
YES
Is the F7501 fuse in the inverter unit
circuit functioning?
YES
Is the VCC power supplied to the
inverter control IC (IC7501) on the
inverter unit?
YES
Are there control signals (INV-OFL,
INV-BRT, INV-OSC, INV-STB (ON))
at CN7502 on the inverter unit?
YES
Is the specified control signal
inputted at IC7501 (INV-CTL) on the
inverter unit?
YES
Are the Q7528 and Q7525
transistors at the primary side of
T7501 functioning?
YES
Is the secondary circuit of T7501
functioning?
TROUBLESHOOTING TABLE
Backlight failure to light up
NO Check the individual fluorescent
tubes for light-up failure.
NO
Check the connection between
power unit and inverter unit.
Replace the blown-out F7501 fuse on
NO
the inverter unit. Turn on the power
again. If the fuse gets blown out
again, check the short-circuited spot.
Check the circuit connected with the
NO
VCC terminal on the inverter control
IC (IC7501).
Are there the INV-OFL, INV-OSC,
NO
INV-STB (ON/OFF) signals at P1701
on the main PWB?
NO
Check the line between CN7502 and
IC7501.
NO
Replace IC7501 (INV-CTL) or check
its peripheral circuits.
Replace T7501 or the T75**
NO
transformer for the fluorescent tubes,
or check their peripheral circuits.
(Continued)
YES
YES
NO
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56
Replace any defective fluorescent
tube (s) with new one (s).
Check T7501 and T7502 and their
peripheral circuits as well as IC7501
and their peripheral circuits.
Check pins (5), (7) and (8) of IC1710
(main PWB).