Kenwood TH-K4AT Service Manual page 56

U
TH-K4AT/K4E
TX-RX UNIT (X57-675X-XX)(A/3)
5T
+B
RF AMP
Q9
RF SW
2SC5488
D8
R347
150
HSC277
2.03V
D9
HSC277
RF SW
4.91V
5T
VGG
5T
TEMP
FINAL
Q13
2SK1830
5T
APC
CIRCUIT
OPERATION
5R SWITCH
KAPC
L28 L29
12n
15n
C136
38.85MHz
1st IF
XF1
L71-0619-05
L27
R90 C128 R88
680n
330 0.01u 330
5R
BPF/APC
X57-675X-XX D44
2-71 TH-K4E E NO
0-21 TH-K4AT M2 B30-2205-05 B30-2205-05
Reference voltage value are measured when the power supply voltage is 13.8V(DC IN).
X57-675 5/5
V
T:4.31V T:4.86V
R:0V R:0V
C65 10p
DRIVE
1.43V
AMP
Q10
2SC4926YD
Q15
2SC4617(R)
Q10 OPERATION SW
10.56V
Q12
POWER
2SK3476
AMP
T:0V
R:0V
CN10
Q12 GATE
VOLTAGE SW
Q58
2SK1830
2.30V
(HIGH POWER)
R76 150k
(D)
APC
DIFFERENTIAL
C108
R74 100k
AMP
(D) 100p
IC2 NJM2904V
1 8
AOUT V+
2 7
A-IN BOUT
3
6
R75 A+IN B-IN
4 5
GND B+IN
100k (D)
R79
470p
C110
150k (D)
C356 0.01u
+B
C137
7p
5p
1st MIXER
4.56V
RX BPF TUNING
Q16
3.10V
3SK318 C140
2.80V
C142 4p (B)
470p
5R
D47 D60 D62 D63 R230
NO MA2S111 MA2S111 NO NO
NO NO MA2S111 220
W
SCHEMATIC DIAGRAM
C326
C68 R271
1.98V
12
10p
470p
C363
10p
R34
3.3k
VOLTAGE
DROP
5T
VGG
ANTENNA SW
L17 C89
2.5n
33p
HVC131
HVC131
ANTENNA SW
R61 270
R62 270
APC OUTPUT SW
Q14
RN4902
R85
R81 390k
C112 470p
R83
APC
56k
KAPC(APC KILL)
D14
REVERSE CURRENT PREVENTION
D18,19
C146
4.56V
3.14V
4p (B) L36
4.30V
56n
Q17
3SK318
RX 1st AMP
C374 C512
100p 100p
NO NO
X Y
10.37V
C329
C364 C75
18p 470p
12p
Q11
2SK2596
DRIVE
AMP
VDD
D10
L20 L21 L22 L30
4T 4T 4T
4T
C94
470p C96 1p C98 2p C100 2p
D11
(B) (B) (B)
OVER INPUT
PROTECTION
D12,13
ANTENNA SW
5T
560
TEMP COMPENSATION
D15
APC OUTPUT
VOLTAGE LIMITTER
D20,21
RX BPF TUNING
C159 3p C165 3p
C156
470p
(B) (B)
C162
470p
5R
Note : The components marked with a
dot ( ) are parts of layer1.
1
L15
4.7n
2
ANT
R289
0
3
4
5
R353 R352
0 0
6
7