BOXLIGHT MP-45, Руководство по обслуживанию

Страница: 50 / 130

-50-
Troubleshooting
No Sound
1. No audio signals at AV input circuit.
Check audio signals at pins 1, 12 (CG1), 5, 14 (CG2) and
2, 15 (VIDEO) of IC5001 on AV Board. Check IC5001 and
peripheral circuits.
2. Incorrect operation of Input mode switching.
Check AUDIO_SW1/AUDIO_SW2 switching signals at pins
9 and 10 of IC5001. The AUDIO_SW1/AUDIO_SW2 sig-
nals are output from pins 4 and 5 of IC1801. See the truth
table below for input mode selection.
3. No audio output signal at speakers.
Check audio signals at pins 3, 4 and 1, 2 of K16S on M
Drive Board.
Check MUTE signal at pin 8 of K16R/K8T.
The MUTE signal is output from pin 49 of IC1801.
Mute On : High
Check MUTE signal at pins 3 and 14 of IC1652.
Check SP OFF signal at pin 9 of K16R/K8T.
The SP OFF signal is output from pin 8 of IC1801 and sent
to pin 7 of IC1631/IC1632 through Q1681/Q1682.
SP OFF signal from IC1801 : High
Check SP OFF signal at pin 7 of IC1631/IC1632.
SP OFF signal to IC1631/IC1632 : Low
Check sound volume signal at pin 7 of K16R/K8T.
The VOLUME signal is output from pin 8 of IC9405 and it
is controlled by IC801 via the IIC bus.
Volume Min.: Low
Check audio signals at IC1651,IC1631, IC1632 and periph-
eral circuits.
4. No power supply at audio circuit.
Check 9VA(9V AUDIO) power supply line.
Logic Table of IC5001
Pin 10 Pin 9 Mode
L L COMPUTER 1
H L COMPUTER 2
L H VIDEO
Q5002
Q1681/Q1682
Q5001
Q5005
Q5006
Q5007
2
15
2
5
3
15
5
14
1
12
2
3
3
6 5
1 2
10
9
10
3,14
7
7
1
12
7
7
5
5
14
17
14
17
13
4
5
8
49
Mute: H
Mute: H
Mute: L
Monitor out ON : L
Monitor out OFF : H
8
43 45 41
3
4
1
2
K10T
K30P
K16R
K10A
K30Q
K10B
K8T
K16N
K16S
IC801
CPU
IICSCL
IICSDA
AU SW1
A MUTE
SP OFF
VO
LUME
VOLUME
AU SW2
A SW1
A SW2
SP OFF
29
30
31
30
WRL CPU
READ CPU
48
43
MAIN BOARD
M DRIVE BOARD
AV BOARD
IC1652
A
UDIO-CONTR
OL
<BH3540>
IC1631
L-AMP.
<TDA7056>
IC1632
R-AMP.
<TDA7056>
IC1651
PRE AMP.
<EL2244>
L
R
L
L
R
L
R
L
R
VIDEO
AUDIO-IN
PC2
AUDIO-IN
PC1
AUDIO-IN/OUT
(VARIABLE
OUTPUT
for PC2 only)
SP901
SP902
L
R
IC1801
I/O EXP
ANDER
<M66500>
IC9405
DAC
3 18
DATA 1
91
IC9883
F.F.
IC5002
SW
R
A MUTE
9 8
7
IC5001
A
UDIO-SW
<4052>
A MUTE
M OUT
3
1
5
6
23
Audio signal processing circuit