Kenwood TH-K20A Service Manual page 28

K
TH-K20A/K20E
SHIFT
D3
THERM
CV RF SWITCH
L1 D2
220n
1SV325F
D1,2
FREQUENCY
CONTROL
D 11
VCO
SPEED UP
C3
MOD R4
1u 15k
C2
R3
0.033u 1k
R48
1k
D1 1
DA2S101
CURRENT
VDCSW
R27
2.2k
5MS
R31
PLPS
10k
PLLD
Q6
LTC014EEBFS8
DC SW
CURRENT
STEERING
DAT
CLK
PLLE
5C
LSDI
VOLCS
D/A CONVERTER
+B
1
VIN2
2
VDD
R300
1k
3
LD
R301 1k
4
CLK
R302
1k
5
DI
6
VIN3
LSDO
C304
0.047u
CVDET
5VC
VOX
R308
1k
5R
W/N
RSSI
5T
SQL
28
X57-821 1/1 X57-821 3/4
L
SCHEMATIC DIAGRAM
D5
D4
Q3
FREQUENCY MCH3914(7)-H
MODULATOR
CONTROL
VCO
C5
39p
C6 L 6
L3
10u 10u
0.022u
2SC5383-T111
R9
100k
Q1
LTC014EEBFS8
SHIFT
Q1
TX/RX SW
5MS
PLL SYSTEM
4.98V
IC1
MB15E03SL-E1
C46
9 CLo CK 8
FIN
C42
1000p
10 DATA 7
XFIN
1000p
6
1 1 LE
G ND
1 2 P S 5
Do
4
1 3 Z C
VCC
3
14 LD/FoUT
VP
15 P 2
oSCoUT
16 R 1
oSCIN
R36 10k
R37 10k
R38 10k
T0
VCoNT
GND
L77-3074-05
LSDI
POWC
C 305
1u
5MS
18
VIN7
17
GND
16
R2A20178NP2 RESET
IC300 15
VDAREF2
14
VDAREF1
13
VIN6
CURRENT
STEERING
KDR731
C306
1u
D300
M
R15 47k
R10
0.70V
Q4
1.80V
22
2SC5108(Y)F C27
C22
47p
0.5p
RF BUFFER
C28
4.15V
9p
L10
27n
Q2
RIPPLE FILTER
D6
SPEED UP
THERM
CURRENT
VDCSW
VOLTAGE
REGULATOR/3V
Q7
2SC5383-T111
2.90V
C45
22p
TCXO
X1
19.2MHz
VCC
L13
C51
oUTPUT
4.7n
22p
+B
5C
BPF
AF FILTER
R385
1k
IC302
NJM12904RB1
R322
8 V+ 1
AoUT
3.3k
7 BoUT
2
A-IN
C319
R319 C320
6 B-IN 3
A+IN
180
0.18u 0.18u
5 B+IN 4
GND
C318
R:1.80V
0.18u
T:1.81V
R320 R369 R321
2.2k
56k 0
Q300
LTA023JEBFS8
5MS
DC SW
MIC AMP/LIMITER
IC304
NJM12904RB1
1
V+
- +
R335 R337 R338
+ -
10k 10k 10k
4
GND
0.01u
C337
C338 1000p
5R
W/N
RSSI
5T
SQL
N
TX-RX UNIT (X57-821X-XX)
C34
15p
RF AMP HSC277
Q5
2SC5636
C31
HSC277
12p
D7,8
TX/RX SW
5C
5.0V
5MS
LSD BUFFER
IC301
NJM12904RB1
1 8
V+
2 7
- +
R315
3 6
+ -
560k
4 5
GND
LSDI
5MS
5R
R:4.89V
T: 1.59V
R328
10k
QT/DQT FILTER
R329
IC303
NJM12904RB1 330k
8 V+
1
7 R327
2
+ -
R325 100k
6 3
- +
470
5
4
GND
C324
0.18u
R326
5.6k
5VC
R342
560k
8
C339
10p
5
O
D8
R:1.03V
T:1.74V
D7
RXLO
R:4.88V
T: 1.59V
THERM
CURRENT
VDCSW
TCXO OUT
+B
POWC
BPF
5R
W/N
RSSI
5T
SQL