Sanyo PLC-XP41, Service Manual

Page: 37 / 122

-37-
The possible causes of No Picture are listed below. Please
check following and refer to video signal processing dia-
grams in the figure opposite.
1. No picture from Video source
Composite Video Input
Check composite video signal at pins 3 and 4 of K10R on
AV Board and K8A on Main Board.
Check Y, C signals at pins 15 and 14 of IC1141.
Check Y, C signals at pins 5 and 7 of IC3101.
Check IN2/IN3 signal at pin 22 of IC101.
IN2 : Low, IN3 : High
S-Video Input
Check S-video signals at pins 47-48 (Y), 51-52(C) of
K10R and K8A.
Check Y, C signals at pins 43 and 44 of IC3101.
Component Input
Check component signals at pins 7-8 (Pb), 11-12 (Pr) and
3-4 (Y) of K10R and K8A.
Check component signals (Y, Pr, Pb) at test points
TP4111PB, TP4111PR and TP4111Y.
Check IN2/IN3 signal at pin 22 of IC101.
IN2 : Low, IN3 : High
All of video signals
Check component signals (Y, Cr, Cb) at test points
TP401CR, TP401CB and TP401Y.
Check component signals (Y, Cr, Cb) at pins 67, 68 and
69 of IC4101.
Check component signals (Y, Pr, Pb) at pins 73, 74 and
75 of IC4101.
Check Sync signals (AV_HSYNC, AV_VSYNC) at pins 4
and 9 of IC3101.
Check Sync signals (AV_HSYNC, AV_VSYNC) at pins 65
and 66 of IC4101.
Check RGB signals at pin 35, 37 and 39 of IC4101.
Check RGB signals at pins 15, 14 and 4 of IC4181.
Check RGB signals at pins 8, 10 and 12 of IC201.
Check Sync signals (AV_HSYNC, AV_VSYNC) at pins 1
and 3 of IC3231.
Check CG/HD switching signal at pin 22 of IC201 and
pins 9, 10 of IC3231.
CG : Low, HD : High
2. No picture from Computer source
Check RGB signals at pins 19-20, 23-24 and 27-28 of
K10Q on AV Board and K8B on Main Board.
Check Sync signals (CG_HSYNC, CG_VSYNC) at pins
11-12 and 13-14) of K10Q on AV Board and K8B on Main
Board.
Check RGB signals at test points TP20R, TP21R, TP20G,
TP21G, TP20B and TP21B.
Check sync signals at test point TPHS and TPVS.
Check CG1/CG2 switching signal at pin 22 of IC5201 and
pins 16 of IC5204. The CG1/CG2 switching signal is out-
put from pin 50 of IC1801.
CG1 : Low, CG2 : High
Check CG/HD switch signal at pin 22 of IC201 and pins 9,
10 of IC3231. The CG/HD signal is out put from pin 52 of
IC1801.
CG : Low, HD : High
3. No picture from both of Video and Computer
sources.
Check RGB signals at test points TP20R, TP21R, TP20G,
TP21G, TP20B and TP21B.
Check HSYNC signal at test point TPHS and VSYNC sig-
nal at TPVS.
Check clamping signals at IC211 and IC212.
4. No picture from DVI source.
Check 5V power supply(5VDVI) at pins 1 and 2 of K10P.
Check Sync signal at pins 47 and 48 of IC8001.
Check ICs IC8001 and peripheral circuits.
5. No picture from all of sources
Check RGB S&H signals at test points TP501, TP1501,
TP531, TP1531, TP561 and TP1561.
Check NRS signal at test point TP2551.
Check power supply circuit 15.5V and 15VP and peripher-
al circuit.
Check ICs IC501, IC531, IC561, IC1501, IC1531, IC1561,
IC9401, IC401, IC3301 and peripheral circuits.
Troubleshooting
No Picture
SIGNAL K10Q/K8B
CG1/CG2-SW 5-6
H-Sync 11-12
V-Sync 13-14
B 19-20
G 23-24
R 27-28
SIGNAL K10R/K8A
AV_Y/Video 3-4
AV_PB 7-8
AV_PR 11-12
S_SW-IN 15-16
IN2/IN3-SW 33-34
S-Y 47-48
S-C 51-52