No Picture - Canon LV-S4 Service Manual

Troubleshooting
● No Picture
Check following steps.
No picture with all of
input sources
No
No picture with Computer
RGB input source
No
No picture with Computer
RGB(Scart) input source
No
No picture with S-VIDEO
input source
No
No picture with
Component input source
No
No picture with video
input source
Yes
Check signal processing stage and LCD driving stage;
Check RGB S&H signals at test points TPR1, TPG1, TPB1.
Check NRS signals at test points TP2531 and TP2561.
Check power supply circuit 15VP and peripheral circuit.
Check ICs IC501, IC531, IC561, IC3531, IC401, IC9401, IC301 and
peripheral circuit.
Yes
Check PC source selecting stage;
Check IC5201 and peripheral circuit on the AV board.
Check RGB signals at test points TP6202R/G/B.
Check H/V_SYNC signal at test points TPGHS/TPGVS.
Yes
Check PC source selecting stage;
Check RGB signals at pin 3, 2 and 1 of IC101.
Check CV_SCART signal and test points TPVHS/TPVVS.
Yes
Check AV source selecting stage;
Check S-video signal (Y/C) on the AV and Main board.
Check IC101, Video decoder, and peripheral circuit.
Yes
Check AV/PC source selecting stage;
Check component signal (Y/Cr,Pr/Cb,Pb) on the AV and Main board.
Check IC5201, IC8201, IC101 and peripheral circuit.
Check H/V_sync signal at test points TPGHS/TPGVS/TPVHS/TPVVS.
Yes
Check AV source selecting stage;
Check composite video signal (Video) on the AV and Main board.
Check IC101 and peripheral circuit.
* Following information differs from the model LV-S3 ;
- S-video input source
RGB signals are selected at RIN1/GIN1/BIN1 of IC5201 and sent
to IC8201, A/D converter IC.
H/V sync signal is output from IC5201 and sent to IC301 through
IC5301 and IC5303.
GSYNC signal of the source without H/V sync signals is output
from IC5201, and sent to IC5301 and IC5302, then sync separat-
ed signals are sent to IC301 through IC5303.
PC/AV_SW signal is applied on IC5303, output from pin 14 of
IC3551 for selecting sync signals.
RGB(Scart) signals are sent to IC101, Video decoder IC.
CV_SCART signal for sync is sent to pin 72 of IC101.
S_Y/C signal are sent to pin 73 and 71 of IC101 and they are con-
verted to the component signal in IC101.
Component signals (480i/575i format) are sent to IC101 directly.
Component signals (480p/575p format) are selected at
RIN2/GIN2/BIN2 of IC5201 and other HDTV format signals are
selected at RIN1/GIN1/BIN1 of IC5201, and then sent to IC8201.
Sync signals of 480i/575i format signal are output from IC101.
Sync signals of other format signals are output from IC5302.
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