3-18
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Only for training and service purposes.
PGND
C744
100nF
IC701
1
VAA
2
GND
3
IN-
4
COMP
5
CSD
6
VSS
7
VREF
8
OCSET
9
DT
10
COM
11
LO
12
VCC
13
VS
14
HO
15
VB
16
CSH
C733
NC
+5V_AMP
-5V
R7A1
10
R7B1
10
R751
47K
R755
NC
R750
2.2K
C7A3
100nF
C7A4
100nF
C742
2.2nF
C743
2.2nF
C735
10uF
C745
10uF
C754
10uF
C736
1nF
R765
100
R771
6.8K
R756
200
R776
2.7K
ONE POINT REPAIR GUIDE
9. SPEAKER NO AUDIO
Speaker No Audio
9-1. AMP IC (IC700 ~ IC703)
9-1-1. Solution
Replace IC700 ~ IC703 on MAIN board.
9-1-2. How to troubleshoot (Countermeasure)
1) Check supply voltage of AMP(CN702) & PWM signal
Normal supply voltage and signal
Check AMP IC.
Poor supply voltage
Check SMPS Assy.
Poor signal
Check PWM IC601.
2) Check CSD of FET driver IC (IRS2092).
CSD has about 5 V on normal state.
When AMP has problem, CSD is LOW state or keep change LOW to HIGH.
9-1-3. Service hint (Any picture / Remark)
< MAIN board top view >
< MAIN board top view >
< MAIN - AMP circuit >
CN702
CN702
pin1, 2 : +66 V
pin1, 2 : +66 V
pin3, 4 : PGND
pin3, 4 : PGND
pin5, 6 : -66 V
pin5, 6 : -66 V
pin5 of ICs
pin5 of ICs
CSD
CSD
IC701
IC701