Sharp LC-42SB45U - No Picture on the Display

LC-42SB45U
36
No picture on the display (1)
↓
The picture doesn't appear in all modes.
MAIN UNIT: ↓
↓NO
YES
↓YES
PANEL_UNIT:
↓YES
↓YES
No picture on the display (2)
↓
Does not the picture come out when VHF/UHF is received?
TERMINAL UNIT: ↓
MAIN_UNIT: ↓YES
↓YES
No picture on the display (3)
↓
Does not the picture come out when DTV is received?
TERMINAL UNIT: ↓
↓YES
TERMINAL UNIT: ↓YES
MAIN_UNIT: ↓YES
Is LCD controller's control signal normal?
Is the above-mentioned LVDS signals output to connector CN750?
NO
Check the line between IC U400 and CN750.
NO
Control signals BRIGHT_ADJ, INVERTER_ON_OFF,
PANEL_VCC_ON/OFF, and it peels off and whether normality is
checked.
Check the panel module.
Similarly, is the LVDS signal input to connector of the panel
module?
NO
Wire harness is checked.
Is LVDS signal output from 1st_channel and 2nd_channel of IC U400 in each mode?
(A0N/A0P),(A1N/A1P),(A2N/A2P),(A3N/A3P),(CLK1N/CLK1P),(A4N/A4P),(A5N/A5P),(A6N/A6P),(A7N/A7P),(CLK2N/CLK2P)
Check IC U400 and its peripheral control circuits.
Is picture signal input from pin (4) of TUNER (TU201) to pin (AC26)
of IC U400?
Is TUNER_CVBS signal output from pin (4) of TUNER (TU201)?
NO
Check whether I2C is normally accessed between TU201 and IC
U400.
NO
Check the line between IC U400 and TU201.
Refer to “The picture doesn't appear in all modes.”
Is IF signal output from pin (18), (19) of TUNER (TU201) to pin
(AB24), pin (AC24) of IC U400?
Is the voltage of regulation for a TUNER circuit and the power
supply terminal of Q103 supplied?
NO
Each power supply circuit is checked.
NO
Check the tuner, IC U400 and their peripheral circuits. Replace
as required.
Similarly, is communication control carried out between pin
(12)(SCL), pin(13)(SDA), pin(16)(AGC) of TU201?
NO
NO
Do X300 (60.00MHz) oscillate?
Check X300 and its peripheral circuits.