LC-46XL2E (serv.man4). Troubleshooting Table - Sharp TV Service Manual (repair manual). Page 9

LC-42XL2E/S/RU, LC-46XL2E/S/RU, LC-46X20E/S/RU, LC-52XL2E/S/RU, LC-52X20E/S/RU

4 – 9

                                             
The picture doesn't appear in all modes.

MAIN UNIT:                          
Is LVDS signal output from 1st_channel and 2nd_channel of IC3301(VIDEO PROCESSER) in each mode?
TA1_P/M (A14/B14), TB1_P/M (A15/B15), TC1_P/M (A16/B16), TD1_P/M (A18/B18), TE1_P/M (A19/B19), TCLK1_P/M (A17/B17), TA2_P/M 
(A20/B20), TB2_P/M (C20/D19), TC2_P/M (D20/E19), TD2_P/M (F20/G19), TE2_P/M (G20/H19), TCLK2_P/M (E20/F19)

YES

NO

Check IC3301 and its peripheral control circuits.
(IC2002, IC8101, IC3501, IC3502, etc.)

Is the above-mentioned LVDS signal output to connector P2601?

NO

Check the line between IC3301 and P2601.

                                             

YES

Is LCD controller's control signal normal? 

NO

control signals R/L_LINE, U/D_LINE, TEMP1/2/3_LINE, 
DET_PNL12V, ROMSEL0_LINE, ROMSEL1_LINE, and it peels 
off and whether normality is checked.

PANEL_UNIT:                       

YES

Similarly, is the LVDS signal input to connector SC4801 (XL2E)/
CN4804 (X20E) of the panel module?

NO

Wire harness (LW) is checked. 

 YES

Check the panel module.

                                            
Does not the picture come out when VHF/UHF is received?

TERMINAL UNIT:                 
Is IF signal output from pin (17) of TUNRE (TU7501)?

NO

Check whether I2C is normally accessed between named 
TU7501 and IC7507 (COFDM).

YES

Is IF signal input to pin (1) and (2) of IC7504 (IF-DEMO)?

NO

Check the FL7502 (VIF_SAW) and their peripheral circuits.

YES

Is picture signal input from pin (17) of IC7504 to pin (9) of IC506 
(VIDEO_SELECTOR)?

NO

Check the line between IC7504 and IC506.
(Q7505, IC7508, etc.)

YES

Is CVBS signal (MAIN_Y/V) output from pin (52) of IC506 to pin 
(2) of connector SC501?

NO

Check the line between IC506 and SC501.

MAIN UNIT:                          

YES

Is CVBS signal (MAIN_Y/V) input to pin (2) of connector 
SC1101?

NO

Check the connector SC501/SC1101.

YES

Is CVBS signal (MAIN_Y/V) input to pin (Y4) of IC3301 
(VIDEO_PROCESSOR)?

NO

Check the line between SC1101 and IC3301.

YES

Refer to “The picture doesn't appear in all modes.”