Sanyo PLC-XT10, Service Manual

Page: 47 / 104

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The possible causes of No Picture are listed below. Please
check following and refer to the chapter “Inputs & video sig-
nal processing stage”, “LCD panel driving stage” in the
Chassis Block Diagrams on the previous page.
1. No picture from Video source
Composite Video Input
Check that the composite video signal is observed at the
following points;
Pin 16 of K8D, pins 4, 3 of IC141, pin 4 of IC1141, pin 88
of IC1101 (NTSC), pin 7 of IC2101 (PAL) on the Main
Board.
Check that the Y/C signals are observed at the following
points;
Pins 83, 84 of IC1101, pins 1, 13 of IC1141(NTSC), pins
25, 27 of IC2101, pins 2 12 of IC1141 (PAL), pins 15, 14
of IC1141, pins 5, 7 of IC3101.
S-Video Input
Check that the Y/C signals are observed at the following
points;
Pins 14 (Y), 12(C) of K20Q and K8D, pins 43, 44 of
IC3101.
Component Input
Check that the component signals are observed at the
following points;
Pins 4 (CR), 6 (CB), 8 (Y) on K20Q and K8D, pins 17, 18,
19 of IC3101, pins 73, 74, 75 of IC4101.
All of video signals
Check that the RGB signals are observed at the following
points;
Pin 35, 37, 39 of IC4101, TP13R, TP13G, TP13B, pins
11, 13, 15 of IC3201.
Check that the SYNC signals are observed at the follow-
ing points;
Pins 28, 29 of IC4101, pins 1, 2 of IC6181, test points
TPVD, TPHD, pins 13, 15 , 7, 5 of IC4281.
2. No picture from Computer source
Check that the RGB signals are observed at the following
points;
Pins 1, 3, 5 of IC3001 for Computer2 mode, pins 8, 10, 13
of IC3001 for Computer1 mode, pins 20, 18, 16 of
IC3001, test points TP21R, TP21G, TP21B, pins 5, 13, 20
of IC201.
Check PC1/PC2 switching signal is correct. Computer1:
Low, Computer2 High on pin 22 of IC3001.
Check that the SYNC signals are observed at the follow-
ing points;
Pins 8, 3, 1, 6 of IC3021 and IC3022, pins 2, 5, 13, 11 of
IC7201, test points TP814, TP815, pins 2, 4, 18, 16 of
IC8041, test points THGHS, TPGVS, pins 34, 133 of
IC301.
Check PC1/PC2 switching signal is correct. Computer1:
Low, Computer2 High on pin 2 of IC3021 and IC3022.
3. No picture from DVI source.
Check 5V power supply(5VDVI) at pins 6 and 7 of K10R
and K26D on the power DC board.
Check Sync signal at pins 2, 4, 16, 18 of IC8001.
Check ICs IC8001, IC8061, IC8071, IC8081 and peripher-
al circuits.
4. No picture from all of sources
Check RGB S&H signals at test points TP501, TP531,
and TP561.
Check that the SYNC signals are observed at test point
TPDHS and TPDVS, pins 7 and 8 of IC401.
Check NRS signal at test point TP2531, TP2561.
Check power supply circuit 15.5V and 15VP and peripher-
al circuit.
Check ICs IC501, IC531, IC561, IC3501, IC3531, IC3561,
IC2531, IC2561, IC401 and peripheral circuits.
Troubleshooting
No Picture