Sanyo PLC-XL45, Service Manual

Page: 45 / 102

-45-
troubleshooting
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 TP_B1, TP_G1, TP_R1.
Check power supply circuit 15.5V and peripheral circuit.
Check ICs IC501, IC531, IC561, IC501, IC531, IC561, IC401,
IC301 and peripheral circuits.
Check PC1/PC-switching stage;
Check IC501<PC1/PC-SW> and peripheral circuit.
PC1/PC_SW signal (PC1: L) is output from pin 98 of IC1801<I/O
EXPANDER> and applied to pin 6 of IC501.
PC1:L, PC:H
No picture with PC1
input source only
No picture with PC2
input source only Check PC1/PC-switching stage;
Check IC501<PC1/PC-SW> and peripheral circuit.
PC1/PC_SW signal (PC: H) is output from pin 98 of IC1801<I/O
EXPANDER> and applied to pin 6 of IC501.
PC1:L, PC:H
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.
Monitor-Out: H
Check PC/AV source selecting stage and processing stage;
Check IC501<PC1/PC_SW> and IC801<A/D Conversion> and
peripheral circuit.
No picture with all of
computer input sources
Yes
Yes
Yes
No
No
No
No
Check following steps.
Check AV source selecting and decoding stage;
S-Video source
Check S-video signal (Y/C).
S-C signal is applied to pin 18 of IC101<Video Decoder>, and S-Y
signal is applied on pin 11 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, 13, 13 of
IC101<Video Decoder>.
The component mode is selected by the SCL1 and SDA1 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>.
No picture with video
input sources
Yes