Kenwood TH-K20A Service Manual

26
TH-K20A/K20E
SCHEMATIC DIAGRAM
X57-821 1/1
X57-821 1/4
MIC
SP
LEDG
LEDR
LAMP
KEYO2
KEYO4
KEYO1
KEYI1
KEYI2
KEYIT
KEYI3
KEYI4
ENC2
KEYO3
ENC1
C354 1000p
R358
47k
C347
1000p
R305
10k
Q301
LTC044EEBFS8
D302
RB521S-30
F300
3.15A
R440
47k
C344
270p
1000p
D301
GN1G
R360
1.8k
R372
47k
MIC300
1
2
C369
0.047u
C357
100u
6.3
C364
1u
J300
1
3
11
10
2
C367
1u
R368 270k
R363
1k
S418
C421
1000p
C365
1000p
R351
100
R367
330k
R362
330k
C358
4.7u
C351
1000p
R359
330
R370
470k
Q302
LTC044EEBFS8
R365
2.2k
CN303
C363 1000p
R355
470
R350
18k
R354
1k
C353
0.047u
R446
330
D427
B30-1779-05
R445
220
D426
B30-1782-05
IC308
XC6209B502P-G
1NC
2VSS
3CE
4VIN
5 VoUT
C375
1u
C377
R379
100k
0.01u
C424
C345 100p
J301
1
3
4
2
R364
1k
C366
10u
R377
47k
SSM3J05FU-F
Q308
Q403
RT1N144U-T111
Q404
RT1N144U-T111
R443
100
C356
10u
C423
1000p
S417
CN305
IC307
TA7368PL
1
NC1
2
VCC
3
NC2
4
VIN
5
RIPPLE
6NF
7 PHASE
8 PRE-GND
9 PW-GND
10 PoUT
C373
C372
10u
2SK3577-A
Q303
R374
10k
SSM6J08FU(F)
Q306
C383
1000p
C384 1000p
SSM3J05FU-F
Q304
2SK3577-A
Q305
IC306
XC6209B502P-G
1NC
2 VSS
3CE
4VIN
5
VoUT
C376
C380
1000p
C382
270p
C385
1000p
F301
0.315A
VR300
R353
10k
R361
47k
D418D419
R448
1.2k
D414
B30-2261-05
D415
R444
220
R447
1.2k
D420
R442
330
R449
1.2k
D416
B30-2337-05
D421
D417
D401
DZ2S036(0)
C417
1000p
2SC4617(R)
Q402
C419
10u
12A02CH
Q401
R437
3.3k
C420
1000p
R438
680
R439
33k
C418
1000p
COM0 COM1 COM2 COM3 SEG0 SEG1 SEG2 SEG3 SEG4 SEG5 SEG6 SEG7 SEG8 SEG9 SEG10 SEG11 SEG12 SEG13 SEG14 SEG15 SEG16 SEG17 SEG18 SEG19 SEG20 SEG21 SEG22 SEG23 SEG24 SEG25 SEG26 SEG27 SEG28 SEG29 SEG30 SEG31
S419
C
B
A
CN300
1
2
D423 D422
D425
R450
1.2k
R451
1.2k
D424
R453
100k
R452
100k
R464
27k
R376
0
C359
0.01u
S412
D409
D405
1SS388F
S409
D406
1SS388F
S406
S415
D411
DA2S101
S413
S411
S407
S410
S408
D410
DA2S101
S405
D404
1SS388F
S414
D408
D407
1SS388F
S416
R466
Q307
LTA023JEBFS8
C361
0.22u
C360 0.22u
C379
220p
R378
27k
C381
0.1u
IC305
XC6120N302N-G
1NC 2 VSS
4
VIN
3
VoUT
D304
RB521S-30
R380
2.2
R441
100
R470
47K
R366
0
D305
DZ2S068(M)
R357
560
C371
0.027u
R431
R433
R432
VOL OUT
RESET
PTT
PTT/RXD
MIC
IM
TXD/REM
SPK
5MS
AFO
5M
5MSC
SP MUTE SW
BATT
-
BATT+
SPM
EXPTT
TXD
RXD
SPG
5MS
BATTERY
TERMINAL
REG
+B
SB
SPK
SPG
SB
MONI
AF POWER AMP
SPG
KEY BACKLIGHT
REM
REM
0
D
9
6
#
8
A
42
C
1
B
3
7
5
0-11
0-20
2-71
MONI
LCD
C352
4.7u 1u
0
M
E
K
X57-8210-XX
0-20
0-11
2-71
0
R431
0
NO
0
R432
NO
NO
R433
NO
NO
S401
S402 S403 S404
D414,D415
D416-D425
INT SP
+
-
+B
0.01u
C425
100p
NO
D408
D409
DA2S101
DA2S101
DA2S101
DA2S101
NO
NO
LED
GREEN
LED
RED
DC SW
DC SW
DC SW
DC SW
VOLTAGE
REGULATOR/5V
DC SW
DC SW
DC SW
VOLTAGE
DETECTOR/RESET
VOLTAGE
REGULATOR/5V
PROTECT
POWER SW
/AF VOLIUM
OVER VOLTAGE
LIMITTER
LED SWITCH
BACKLIGHT
CONTROL
SWITCH
REVERSE CURRENT
PREVENTION
D304
REVERSE CURRENT
PREVENTION
REVERSE CURRENT
PREVENTION
D404-407
Key matrix
D408-D411
SURGE
ABSORPTION
BACKLIGHT
DC SW
5MS
5MS
5MSC
RESET
SPM
5CC
5TC
REM
INPTT
RXD
EXPTT
REM
TXD
5CC
5TC
5RC
5RC
5M
+B
SB
5C
5R
5T
TX-RX UNIT(X57-821X-XX)
D401
INT MICINT MICINT MIC
ENC
+B
GND
INPTT
SB
LCD BACKLIGHT
C374
0.056u
7.5V
5.01V
ON:7.49V
OFF: 0.33V
AF AMP
AF AMP
ON:3.30V
OFF: 0.51V
AF AMP
ON:4.99V
OFF: 0V
R:4.89V
T: 1.59V
7.5V
OFF:0.40V
ON:5.57V
OFF:0V
ON:4.98V
OFF:0V
ON:5.02V
ON:2.75V
OFF: 0V
ON:5.0V
GREEN LED
ON:5.0V
RED LED
A
B
C D
E
1
3
4
5
6
7
2

Kenwood TH-K20A Specifications

General

Brand	Kenwood
Model	TH-K20A
Category	Transceiver
Language	English