LC-37HV4E (serv.man8). Troubleshooting table - Sharp TV Service Manual (repair manual). Page 3

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?

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

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.

Are the main unit and the 
inverter 3 unit connected 
properly by the harness?

YES

NO

Connect properly or replace 
the harness.

Is the input voltage at pin (2) of 
IC2004 (micro-processor) 5V?

YES

Failure of thermistor of TH3801.

YES

NO

Failure of pin (2) of IC2004 
(micro-processor).

The backlight does not light up.

Is any of the fuses of 
F7501- F7504, F7551- 
F7553, F7611-F7614 and 
F7641-F7643 burned out?

Check the inverter circuit 
downstream from the 
burned-out fuse.

YES

YES

NO

Is a control signal 
appearing at pin (2) 
(OFL1) and pin (3) (OFL2) 
of P7506 and P7616?

Is power supplied to each 
unit?

Check the opposite 
inverter circuit of the pair.

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 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.

NO

NO

Are the main unit and the inverter 
1 and 3 units connected properly 
by the harness.

YES

YES

Check the circuits around IC4501 
in the main unit and check the 
operation of Q7704 and Q7705.