1.2 No Sound

1) Main board

1. Check that the PC/AV switching signal is correct.

Pins 10 and 11 of IC5001...................AV : L, PC : H

2. Check that audio signal is observed at following points.

Pins 11-12(PC)/13-14(AV) of K10B/K50B

3. Check that the MUTE signal is correct.

Pin 5 of K5A.......................................Mute-On: H

4. Check that the MUTE signal is correct.

Pin 12 of IC1803 ................................Mute-On: L

5. Check that the PC/AV switching signal is correct.

Pin 16 of IC1804 ................................AV : L, PC : H

2) Audio board

1. Check that sound volume control signal is correct.

Pin 4 of IC001

2. Check that audio signal is observed at pin 2 of IC001.

3. Check the MUTE signal at pin 3 of IC001.

Pin 3 of IC001....................................Mute-On: H

4. Check that Vcc-voltage(+12V) is applied at pins 1 and 9 of IC001.

Part 4: Troubleshooting

4-6

Fig. 4-2

PC/AV
SUDIO
SW
IC5001
AV BOARD
AUDIO BOARD
MAIN BOARD
Q5007
SP901
SPEAKER
L
R
15
3
2
4
16
12
16
13
12
16
144
12
4
6
8
1
3
2
8
10,11
1
13
2
12 14
Q5008
PC/AV-SW
Q1801
AUDIO
OUTPUT
IC001
BUFFER
IC851
DAC
IC431
I/O
EXPAND.
IC1804
I/O
EXPAND.
IC1803
I/O
EXPAND.
IC1806
SYSTEM
CONTROL
&
SCAN CONV.
IC301
AUDIO INAUDIO
OUT
PC LPC RAV LAV RLR
VOL
AUDIO
DAC
SDATA
SCLK
DAC
SDATA
SCLK
MUTE MUTE
Q5041
Q5001
Q5003
Q5002
Q5004
Q5042
BUS