LC-46XL2E (serv.man4). Troubleshooting Table - Sharp TV Service Manual (repair manual). Page 13

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

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Does not the picture of the Y/C video signal input to EXT1 go out?
Does not the picture of the Y/C video signal input to EXT2 go out?

TERMINAL UNIT:                 
<EXT1>
Is Y/C video signal sent to pins (20) and (15) of SCART1 
(SC502)?

NO

Check the setting of an external input device that connects of 
SC502.

<EXT2>
Is Y/C video signal sent to pins (20) and (15) of SCART2 
(SC503)?

NO

Check the setting of an external input device that connects of 
SC503.

YES

<EXT1>
Is Y/C signal sent to pins (67), (69) of IC506?

NO

Check the line between SC502 and IC506.

<EXT2>
Is Y/C signal sent to pins (73), (75) of IC506?

NO

Check the line between SC503 and IC506.

YES

Is Y/C signal output to pin (2), (4) of connector SC501 from pin 
(52/Y), (50/C) of IC506?

NO

Check the line between IC506 and SC501.

MAIN UNIT:                          

YES

Is Y/C signal sent to pins (2), (4) of connector (SC1101)?

NO

Check the connector (SC501/SC1101)

YES

Is Y/C signal sent to pins (Y4), (V9) of IC3301 
(VIDEO_PROCESSOR)?

NO

Check the line between SC1101 and IC3301.

YES

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