No Picture - Sanyo PLC-XE31 Service Manual

Troubleshooting

No Picture

Check following steps.
No picture with all of
input sources
No
No picture with PC1
input source only
No
No picture with PC2
input source only
No
No picture with all of
computer input sources
No
No picture with video
input sources
Yes
Check signal processing stage and LCD driving stage;
Check RGB S&H signals at test points TPB1, TPG1, TPR1.
Check power supply circuit 15.5V and peripheral circuit.
Check ICs IC501, IC531, IC561, IC401, IC301 and peripheral circuits.
Yes
Check PC1/PC2-switching stage;
Check IC5201<PC1/PC2-SW> and peripheral circuit.
PC1/PC2_SW signal (PC1: L) is output from pin 98 of IC1801<I/O
EXPANDER> and applied to pin 26 of IC5201.
Yes
Check PC1/PC2-switching stage;
Check IC5201<PC1/PC2-SW> and peripheral circuit.
PC1/PC2_SW signal (PC2: H) is output from pin 98 of IC1801<I/O
EXPANDER> and applied to pin 26 of IC5201.
MONIT_OUT signal (Monitor-Out:H) is output from pin 139 of
IC301<System Control> and applied to pins 1 and 7 of IC4071<Sync
SW> and pins 3, 6, 16 of IC 4001.
Yes
Check PC/AV source selecting stage and processing stage;
Check IC5201<PC1/PC2_SW> and
peripheral circuit.
Check AV source selecting and decoding stage;
S-Video source
Check S-video signal (Y/C).
S-C signal is applied to pin 128 of IC101<Video Decoder>, and S-Y
signal is applied on pin 121 of IC101.
S_SW signal (S-VIDEO:L) is input to pin 8 of IC1801<I/O EXPANDER>.
Check component signal (Y/Cr,Pr/Cb,Pb).
Component video source
The component signals are applied to pins 139, 132, 123 of
IC101<Video Decoder>.
The component mode is selected by the SCL0 and SDA0 signal
applied to pins 67 and 68 of IC101.
Composite video source
Check composite video signal (Video).
The composite video signal is applied to pins 119 of IC101<Video
Decoder>.
PC1:L, PC2:H
PC1:L, PC2:H
Monitor-Out: H
-46-
IC8201<A/D Conversion> and