BOXLIGHT CP-300t, Руководство по обслуживанию

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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 45 and 46 of K10U
on AV Board and K3U on Main Board.
Check Y, C signals at pins 7 and 9 of IC2101.
Check Y, C signals at pins 5 and 7 of IC1101
S-Video Input
Check S-video signals at pins 39, 40 (Y), 41, 42 (C) of
K10U and K3U.
Check Y, C signals at test points TP11SC and TP11SY.
Check Y, C signals at pins 43 and 44 of IC1101.
Component Input
Check component signals at pins 49, 50(Pb), 51, 52 (Pr)
of K10U and K3U.
Check component signals (Y, Pr, Pb) at test points
TP11CV, TP11PB and TP11PR.
All of video signals
Check component signals (Y, Cr, Cb) at pins 21, 22 and
23 of IC1101.
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 IC1101.
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 14, 4 and 15 of IC3101.
Check blanking signal at pin 9, 10, 11 of IC3101.
Check RGB signals at pins 1, 3 and 5 of IC5241.
Check Sync signals (AV_HSYNC, AV_VSYNC) at pins 2
and 12 of IC6261.
Check AV/PC switching signal at pin 22 of IC5241 and
pins 10 and 11 of IC6261.
AV : Low, PC : High
2. No picture from Computer source
Check RGB signals at pins 3-4, 7-8 and 11-12 of K10T on
AV Board and K3T on Main Board.
Check Sync signals (PC_HSYNC, PC_VSYNC) at pins
15-16 and 19-20) of K10T on AV Board and K3T on Main
Board.
Check RGB signals at pins 12, 10 and 8 of IC5241.
Check Sync signals at pins 1 and 13 of IC6261.
Check AV/PC switching signal at pin 22 of IC5241 and
pins 10 and 11 of IC6261.
AV : Low, PC : High
3. No picture from both of Video and Computer
sources.
Check RGB signals at test points TP52R, TP52G and
TP52B.
Check RGB signals at test points TP201R, TP5201G and
TP201B.
Check HSYNC signal at test point TP205.
Check Sync signals at test points at TP62H and TP62V.
4. No picture from DVI source.
Check 9V power supply(9VMCI) at pins 33-36, (3.3V) at
pins 39-40 of K10W and K2W, and (5VD) at pins 3-4 of
K10V and K3V.
Check Sync signal at pins 16 and 18 of IC8081.
Check ICs IC8001, IC7021, IC7031 and peripheral cir-
cuits.
5. No picture from all of sources
Check RGB S&H signals at test points TP25B1, TP25B2,
TP25G1, TP25G2, TP25R1 and TP25R2.
Check NRS signals at test points TP3551 and TP3581.
Check power supply circuit 15.5V and 15VL and peripher-
al circuit.
Check ICs IC501, IC531, IC561, IC1501, IC1531, IC1561,
IC3501, IC3531, IC3561, IC801, IC301, IC401and periph-
eral circuits.
Troubleshooting
No Picture
SIGNAL K10T/K3T
V-Sync 19-20
H-Sync 15-16
B 11-12
G 7-8
R 3-4
SIGNAL K10U/K3U
Video 45-46
S-C 41-42
S-Y 39-40
PB 49-50
PR 51-52