Read Panasonic KX-AT7730RU Service Manual online
11
KX-AT7730 Series
4.2.5.
HANDSET CIRCUIT
1) Transmission Signal Path
The input signal for the handset microphone is sent through the telephone line via the following path:
Handset MIC(JK2)
Handset MIC(JK2)
→ JK3 → C24 → R26 → C34 → Q5 → C21 → R21 → Q3 → C4 → T1 → C3 → Q1 → D1 → Telephone Line
2) Reception Signal Path
The input signal from the telephone line is sent to the receiver through the following path:
Telephone Line
Telephone Line
→ D1 → Q1 → C3 → T1 → C4 → Q3 → R10 → C8 → R12 → Q4 → C26 → R32 → IC10 → C32 → R34 → C27 →
R208
→ Q8 → C31 → JK3 → JK2 → Handset Speaker
C21
T1
1
3
4
6
C3
C2
R4
R1
R2
JK1
1
H
2
T
3
R
4
L
D1
4
3
1
2
R21
R41
R8
R9
R15
R16
R14
+6V
R13
C8
R12
R10
C9
PC1
1
2
3
4
R3
R5
NC
C1
R7
R6
C4
C41
AG
AG
AG
AG
H
T
R
L
NC
C11
NC
C10
C6
NC
C5
Q3
Q4
Q2
Q1
DG
R17
NC
C13
C12
C7
C14
D9
Q11
1
B1
2
E
3
B2
4
C2
5
C1
Q12
1
B1
2
E
3
B2
4
C2
5
C1
IC5
1
I/O1
2
O/I1
12
CONT4
13
CONT1
3
O/I2
14
VDD
4
I/O2
11
I/O4
5
CONT2
10
O/I4
6
CONT3
9
O/I3
7
VSS
8
I/O3
C24
C27
C34
C208
C213
C22
C29
C84
C23
C209
C28
C30
R31
R30
R73
R23
R36
R37
R208
R24
R22
R84
R26
R25
R29
R27
R74
C207
NC
AG
R19 NC
R20 NC
AG
AG1
AG
AG
C214 NC
D3.3V
AG
G
A
G
A
AG
R38
AG
JK2
1
2
3
4
2
3
4
5
JK3
1
2
5
3
4
4
C211
N5
N6
N7
N8
SP1
SP2
M2
M1
AG1
R28
CN8-3
CN8-6
CN8-4
CN8-7
CN7-5
CN7-4
CN7-1
CN7-2
Q6
Q10
Q21
Q22
AG
A5V
J2
NC
J3 NC
Q5
Q8
R39
R40
C250
L1
L7
NC
L6 NC
C25
C31
L5
D41
NC
CN8
CN7
Split PCB 1
D30
C131
C32
C33
C130
R240
R231
C26
R32
R289
R76
R238
R234
R230
R233
R237
R236
R77
AG
AG
AG
R235
N
C
C133
NC
AG
AG
AG
AG
AG
AG
R34
IC10
1
AOUT
2
A-IN
3
A+IN
4
GND
5
B+IN
6
B-IN
7
BOUT
8
V+
Q9
C132
C35
C36
R232
L2
Circuit Diagram
HEAD SET
HS_VOL2
HS_VOL1
HS_MUTE
T_CONT2
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