Sharp LC-37HV4M Service Manual page 24

LC-37HV4M
LC-37HV4H
TROUBLE SHOOTING TABLE (Continued)
Noise appears on the moving image when the QS drive is turned ON.
Is OSTEMP.AD on the 3rd page
of the process adjustment
mode set to 255?
YES
Are the audio unit and the
inverter 4 unit connected
properly by the harness?
YES
Are the inverter 3 unit and the
inverter 4 unit connected
properly by the board-to-board?
YES
Are the main unit and the
inverter 3 unit connected
properly by the harness?
YES
Is the input voltage at pin (2) of
IC2004 (micro-processor) 5V?
YES
Failure of thermistor of TH3801.
The backlight does not light up.
Is any of the fuses of
NO
F7501- F7504, F7551-
F7553, F7611-F7614 and
F7641-F7643 burned out?
YES
Check the inverter circuit
downstream from the
burned-out fuse.
NO
Check IC4701, IC4901 and
the circuits around them.
NO
Check IC4701, IC4901 and
the circuits around them.
NO
Connect securely or replace
the board-to-board.
NO
Connect properly or replace
the harness.
NO
Failure of pin (2) of IC2004
(micro-processor)
Is a control signal
NO
appearing at pin (2)
(OFL1) and pin (3) (OFL2)
of P7506 and P7616?
YES
NO
Is power supplied to each
unit?
YES
Check the wire connected between the inverter 1 and 3 units, the board-
to-board between the inverter 1 and 2 units and the board-to-board
between the inverter 3 and 4 units.
Check the opposite
inverter circuit of the pair.
24
Are the main unit and the inverter
1 and 3 units connected properly
by the harness.
YES
Check the circuits around IC4501
in the main unit and check the
operation of Q7704 and Q7705.
Check for 15V output in the power
unit.
Check the connection of the
high-voltage (pin 2) wire on the
side of the burned-out fuse and
check the connection of the high-
voltage (pin 2) wire of the
opposite fluorescent lamp of the
pair.