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LC-30AA1M
LC-30AA1H
The backlight does NOt go on.
Is any of the fuses of
F6551-F6556
blown?
YES
Check the inverter
circuit downstream
from the blown fuse.
NO sound comes out. (Checking with the AVC
system connected)
Is power supplied to each IC
on the AUDIO PWB?
YES
Is the audio signal applied to
pin (7) (L-IN) and pin (9) (R-
IN) of P3804?
YES
Is the audio signal applied
to pin (13) and pin (15) of
P3803?
YES
Is the output signal from the
1-bit amplifier applied to
P3903?
YES
Check if the internal/external
switching relay (RY3901)
functions correctly.
Is the control signal applied to
NO
pin (8) (OFL1) and pin (9)
(OFL2) of P6564?
YES
Is power supplied to
Inverter PWB?
YES
Check the Lamp error detection circuit on the Inverter-GND
PWB.
Check the connection of the high-voltage
(pin (2)) wire on the side of the blown
fuse and check that of the counterpart
high-voltage (pin (2)) wire of the
fluorescent lamp on the opposite side.
NO
Check if 5V is supplied to the power
regulator circuit (IC3810, IC3812 and
IC3816) and pin (2) of P3804.
NO
Is the audio signal applied to
pin (13) and pin (20) of
SC2202 on the Monitor PWB?
YES
Perform checking around Q2012 and
Q2014 and check the wire between
Monitor PWB and Audio PWB.
Are the MUTE circuits
NO
(Q3804 and Q3805)
operating?
Perform checking around
NO
IC2004, IC3804 and the
1-bit amplifier.
Is the cord connected correctly
NO
between the LCD Control PWB
and Inverter PWB?
YES
Check the peripheral circuitry of
IC4501 of the LCD Control PWB
and check the operation of
Q7701 and Q7702.
NO
Check the 15V output on the
Power PWB.
NO
NO
26
Check for the AVC
System side for output.
Perform checking
around IC3803 and
IC3808.
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