BOXLIGHT MP-45, Service Manual

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Troubleshooting
No Picture
The possible causes of No Picture are listed below. Please
check following and refer to video signal processing dia-
grams in the figure.
1. No picture from Video source
Composite Video Input
Check composite video signal at pins 3 (Input 2) and 5
(Input 3) of IC4104.
Check AV SEL0/1 switching signals at pins 2 and 4 of
IC4104. (refer to the block diagram)
Check composite video signal at pins 45 and 46 of K30R
on AV Board and K10C 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.
S-Video Input
Check S-video signals at pins 49-50 (Y), 53-54(C) of
K30R and K10C.
Check Y, C signals at pins 43 and 44 of IC3101.
Component Input
Check component signals at pins 41 (Pr), 42 (Pb) and 43
(Y) of IC4101.
Check component signals at pins 3-4 (Y), 7-8 (Pb) and
11-12 (Pr) of K30R and K10C.
Check component signals at pins 2 (Pb), 5 (Y) and 12
(Pr) of IC4531.
All of video signals
Check component signals (Y, Cb, Cr) at test points
TP13GY, TP13BCB and TP13RCR.
Check Sync signals (AV_HSYNC, AV_VSYNC) at pins 4
and 9 of IC3101.
Check Sync signals (AV_HSYNC, AV_VSYNC) at pins 16
and 28 of IC7301.
Check RGB signals at pin 21, 22 and 23 of IC3101.
Check RGB signals at pins 15, 14 and 4 of IC4531.
Check Sync signals (AV_HSYNC, AV_VSYNC) at pins 5
and 7 of IC4281.
2. No picture from Computer source
RGB (Analog) Input
Check RGB(Input 1) signals at pins 1, 3 and 5 of IC1201
and at pins 33, 34 and 35 of IC4101.
( IC4101 is for RGB Video source. )
Check RGB(Input 2) signals at pins 12,10 and 8 of
IC1201.
Check CG1/CG2 signal at pin 22 of IC1201.
IN1 : Low, IN2 : High
Check RGB signals at pins 3-4, 7-8 and 11-12 of K30Q
on AV Board and K10B on Main Board.
Check RGB signals at pins 1, 3 and 5 of IC201.
Check RGB signals at test point TP21R,TP21G and
TP21B.
Check Sync signals (CG_H/VSYNC) at pins 15-16and 17-
18 of K30Q on AV Board and K10B on Main Board.
Check Sync signals (CG_H/VSYNC) at pins 2 and 4 of
IC3224.
RGB (Scart) Input
Check RGB(Scart) signal at pins 1, 3 and 5 of IC1201.
Check RGB signals at pins 3-4, 7-8 and 11-12 of K30Q
on AV Board and K10B on Main Board.
Check RGB signal at pins 25,26 and 27 of IC3101.
Check Scart Sync signal at pins 33 and 34 of K30Q on
AV Board and K10B on Main Board.
Check Scart (composite video signal )Sync signal at pin
41 of IC3101.
RGB (Network) Input
Check RGB signals at pins 8, 10 and 12 of IC201.
Check RGB signals at test point TP21R,TP21G and
TP21B.
Check Sync signals (NET_H/VSYNC) at pins 2 and 4 of
IC3251.
Check CG-OUT signal at pin 22 of IC201.
Network : High, PC Analog : Low
3. No picture from DVI source.
RGB (Digital) Input
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.
4. No picture from all of sources
Check HSYNC signal at test point TPGHS and VSYNC
signal at TPGVS.
Check RGB S&H signals at test points TP501, TP531 and
TP561.
Check PSIG signals at test point TP503 and TP533.
Check power supply circuit 15.5V and 15VP and peripher-
al circuit.
Check ICs IC501, IC531, IC561, IC1501, IC1531, IC1561,
IC9401, IC401 and peripheral circuits.
SIGNAL K30Q/K10B
R 3-4
G 7-8
B 11-12
CG_H-Sync 15-16
CG_V-Sync 17-18
CG1/CG2-SW 25-26
Scart-Sync 33-34
SIGNAL K30R/K10C
AV_Y 3-4
AV_PB 7-8
AV_PR 11-12
AV_H-Sync 15-16
AV_V-Sync 17-18
S_SW-IN 37-38
AV SEL-SW 39-42
C-Video 45-46
S-Y 49-50
S-C 53-54