Read Sharp LC-46DH77E (serv.man5) Service Manual online
LC-42DH77E/RU/S/V, LC-46DH77E/RU/S/V
4 – 8
[External input EXT1, EXT2] No picture on the display (4)
Does not the picture of the CVBS signal input to EXT1 go out?
Does not the picture of the CVBS signal input to EXT2 go out?
Does not the picture of the CVBS signal input to EXT2 go out?
Is CVBS signal sent to pin (20) of EXT1 (SC502)?
NO
Check the setting of an external input device that connects with
EXT1.
EXT1.
Is CVBS signal sent to pin (20) of EXT2 (SC501)?
NO
Check the setting of an external input device that connects with
EXT2.
EXT2.
YES
Is CVBS signal from EXT1 (SC502) sent to pin (100) of IC503
(AV_SW.)?
(AV_SW.)?
NO
Check the line between SC502 and IC503.
Is CVBS signal from EXT2 (SC501) sent to pin (6) of IC503
(AV_SW.)?
(AV_SW.)?
NO
Check the line between SC501 and IC503.
YES
Is CVBS signal output from pin (71) of IC503?
NO
Check the IC503 and their peripheral circuits.
YES
Is CVBS signal sent to pin (V4) of IC8101 (DIGITAL AV
DECODER & MAIN CPU & VIDEO PROCESSER) from pin (71)
of IC503?
DECODER & MAIN CPU & VIDEO PROCESSER) from pin (71)
of IC503?
NO
Check the line between IC503 and IC8101.
YES
Refer to “The picture doesn't appear in all modes.”
[External input EXT1, EXT2] No picture on the display (5)
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?
Does not the picture of the Y/C video signal input to EXT2 go out?
Is Y/C video signal sent to pins (20)/Y and (15)/C of EXT1
(SC502)?
NO
Check the setting of an external input device that connects with
EXT1.
EXT1.
Is Y/C video signal sent to pins (20)/Y and (15)/C of EXT2
(SC501)?
(SC501)?
NO
Check the setting of an external input device that connects with
EXT2.
EXT2.
YES
Is Y/C signal from EXT1 (SC502) sent to pins (2)/Y, (86)/C of
IC503 (AV_SW.)?
IC503 (AV_SW.)?
NO
Check the line between SC502 and IC503.
Is Y/C signal from EXT2 (SC501) sent to pins (8)/Y, (92)/C of
IC503 (AV_SW.)?
IC503 (AV_SW.)?
NO
Check the line between SC501 and IC503.
YES
Is Y/C signal output from pins (71)/Y, (70)/C of IC503?
NO
Check the IC503 and their peripheral circuits.
YES
Is Y/C signal sent to pins (V4)/Y, (P4)/C of IC8101 (DIGITAL AV
DECODER & MAIN CPU & VIDEO PROCESSER) from pins
(71)/Y, (70)/C of IC503?
DECODER & MAIN CPU & VIDEO PROCESSER) from pins
(71)/Y, (70)/C of IC503?
NO
Check the line between IC503 and IC8101.
YES
Refer to “The picture doesn’t appear in all modes.”
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