-37-
Troubleshooting
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No Picture
No picture with all of
input sources
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.
No picture with Computer
RGB input source
Check PC source selecting stage;
Check IC5201 and peripheral circuit on the AV board.
RGB signals are selected at RIN1/GIN1/BIN1 of IC5201 and sent to
IC8201, A/D converter IC.
Check RGB signals at test points TP6202R/G/B.
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 separated 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.
Check H/V_SYNC signal at test points TPGHS/TPGVS.
No picture with Computer
RGB(Scart) input source
Yes
Yes
Yes
No
No
No
Check following steps.
Check AV source selecting stage;
Check composite video signal (Video) on the AV and Main board.
Check IC101, Video decoder, and peripheral circuit.
No picture with video
input source
Yes
Check PC source selecting stage;
RGB(Scart) signals are sent to IC101, Video decoder IC.
Check RGB signals at pin 3, 2 and 1 of IC101.
CV_SCART signal for sync is sent to pin 72 of IC101.
Check CV_SCART signal and test points TPVHS/TPVVS.
Check AV source selecting stage;
Check S-video signal (Y/C) on the AV and Main board.
Check IC101, Video decoder, and peripheral circuit.
S_SW signal (S-Video cable is connected:L) is applied on pin 9 of
IC1811.
No picture with S-VIDEO
input source
Check AV/PC source selecting stage;
Check component signal (Y/Cr,Pr/Cb,Pb) on the AV and Main board.
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 select-
ed at RIN1/GIN1/BIN1 of IC5201, and then sent to IC8201.
Check IC5201, IC8201, IC101 and peripheral circuit.
Sync signals of 480i/575i format signal are output from IC101.
Sync signals of other format signals are output from IC5302.
Check H/V_sync signal at test points TPGHS/TPGVS/TPVHS/TPVVS.
No picture with
Component input source
No
Yes
Yes
No
