Icom IC-A25C Service Manual

9-3
TX Line
RX Line
Voltage Line
Explanatory notes
0.001
C381
470P
C102
R102
2.2M
NJM2552V
IC1
1
OSC[B]
2
OSC[E]
3
MIX_OUT
4
GND
5
AM_IF_IN
6
AM_DEC
7
FM_IF_IN
8
FM_DEC
9
FM_IF_OUT
10
QUAD_IN
11
FM_AF_OUT
12
AMP_IN
13
AMP_OUT
14
AM_AF_OUT
15
AM_SW
16
RSSI_OUT
17
RF_AGC_OUT
18
AM_AGC_IN
19
V+
20
MIX_IN
1k
R77
100
R87
0.001
C93
2.2k
R81
0.047
C357
1
C107
0.1
C347
100k
R80
470k
R82
0.01
C99
0.01
C229
47
R290
10k
R73
470P
C100
1kR71
0.01C104
R274
470
0.001
C354
0.1C106
10
R74
R90
220k
0.01
C95
8PC91
10k
R79
0.1C356
39PC201
0.01C321
100k
R76
0.1
C115
0
R94
DMA561030
Q57
1
2
34
5
0.001
C171
R130
2.2k
68k
R266
R115
22k
0.001
C152
6P
C307
33P
C155
0.001
C387
0.001
C313
47
R313
R114
270
0.001
C312
470
R265
15P
C150
0.001
C301
0.001
C308
0.001
C319
R111
10k
0.001
C309
10U
L72
9P
C151
C2012C
L57
R118
15
0.01
C446
4.7k
R254
4.7U
L58
0.5P
C377
0.001
C153
0.001
C156
10U
L71
4.7U
L91
0
R252
Q33 2SC4116
L64
C2012C
0.001
C440
0.1
C444
10P
C438
0.001
C443
0.001
C403
1
C441
10k
R334
100P
C439
680k
R355
1U
L87
1k
R357
1SS390
D25
1SS390
D24
1SS390
D12
1SS390
D11
0.1
C461
0.1
C463
0.1
C462
15k
R374
15k
R376
0.1
C464
0.1
C466
0.1
C467
0.1
C468
LDTA144EE
Q54
12k
R389
12k
R375
12k
R388
12k
R377
1k
R390
5P
C473
6P
C474
56P
C475
AFDET
+5V
VCC
DB2S31400
D40
DB2S31400
D18
LDTC144TE
Q21
LDTC144EE
Q53
22k
R83
0.1
C113
LMV321IDCK
IC22
1
2
3
4
5
100k
R398
0.01
C478
0.01
C479
TC7W53FK
IC2
1
COM
2
INH
3
VEE
4
GND
5
A
6
CH1
7
CH0
8
VCC
TC7S66FU
IC24
1
2
3
4
5
BLM15BD102SN1
EP13
BLM15BD102SN1
EP14
33P
C338
33P
C310
33P
C306
4P
C379
82P
C311
4P
C383
1.8k
R260
1.8k
R258
3.9k
R124
3.9k
R123
0.01
C484
DRA9114T
Q20
LDTC144EE
Q66
0.18U
L88
0.15U
L85
0.18U
L86
3P
C103
47P
C398
100P
C400
56P
C402
4P
C401
11P
C399
10k
R405
L2SC4617S
Q62
0.1
C490
R119
1k
R120
47k
R121
100
R117
220
DB2S31400
D62
4.7
C492
4.7
C493
47k
R432
47k
R433
R99
47k
82k
R100
R101
330k
100P
C98
220k
R75
AK1542A
IC203
1
CPVDD
2
TEST3
3
TEST1
4
LE
5
DATA
6
CLK
7
LD
8
PDN2
9
PDN1
10
REFIN
11
TEST2
12
GPO1
13
GPO2
14
DVSS
15
VREF
16
RFINN
17
RFINP
18
PVDD
19
BIAS
20
PVSS
21
CP
22
CPZ
23
SWIN
24
CPVSS
25
CR-993
X203
VCON
12
GND
3
OUT
4
VCC
1SV323
D38
1SV323
D48
C2012C
L63
33P
C302
1SV323
D45
1SV323
D46
47P
C336
0.001
C508
0.001
C509
R134
470
R135
820
0.001
C510
390
R253
0.33
C349
0.33
C168
2.2
C169
TC7S66FU
IC219
1
2
3
4
5
100
R456
1kR457
2SK880
Q215
10k
R458
56
R122
100PC511
0.1
C515
68k
R459
22
R460
0.1
C174
1
C445
0.1
C514
CR-994
X2
VCON
1 2
GND
3
OUT
4
VCC
1M
R391
820k
R393
560k
R394
1
C355
0.1
C517
0
R461
LDTC144EE
Q216
0.001
C518
10k
R463
0.001
C519
LDTC144EE
Q217
0.001
C520
0.001
C521
0.001
C522
0.1
C172
1k
R359
47k
R407
82k
R464
0.001
C523
0.001
C524
0.001
C525
10P
C526
10k
R465
0
R466
1
C527
0.1
C528
0.1
C529
1
C530
+3V
PSTB
PDATA
PCK
UNLK
2LOC
FC
LVIN
MOD
NARROW2
POW
R5C
RFDETV
TXC
AGCOFF
ANLC
DETMUTE
IFGAIN
NOISE
RSSI
T1
T3
VORDET
VORON
WXC
T2
T4
LTWC450H
FI4
IO
10
C97
22
C173
82N
L67
L38
0.22U
0
R601
PATMP
PATMP
2SC5108
Q60
Q29
2SC5108
Q28
2SC5108
C2012C
L92
5P
C386
5P
C389
1.5P
C170
3699
MP3
1 2
0.001
C390
0.22C512
33P
C315
33P
C335
10
C516
10
C513
LTWC450D
FI2
IO
100k
R462
0.1
C460
0
R401
LDTC144EE
Q243
L1SS400
D92
LDTC144EE
Q68
*R649
*D90
*D89
1k
R650
L1SS400
D91
0.1
C663
10
C101
0.75P
C316
0.75P
C317
0
R651
JTBM450CX24
X1
100k
R637
68k
R467
1k
R381
0.047
C92
150k
R655
R72
56k
2SC5086
Q58
2SC5086
Q59
*R670
*C681*C680
0.1
C682
*FI5
IO
DB2S31400
D93
DB2S31400
D94
22k
R444
0.001 C376
100k
R399
47k
R400
560
R256
560
R262
DETMUTE
AFDET
VORDET
VORDET WXC
ANLC
WXC RSSI
NOISE
R5C
VCC
VCC
PLLSW
SHIFT
2LOC
LVIN
LVIN
FC
FC
AGCOFF
PSTB
PDATA
PCK
UNLK
2LOC
FC
LVIN
MOD
NARROW2
POW
R5C
RFDETV
TXC
AFDET
AGCOFF
ANLC
DETMUTE
IFGAIN
NOISE
RSSI
T1
T2
T3
T4
VORDET
VORON
WXC
NDET
NDET
VORON
VORON
NARROW2
R5S
+3V
+3V
+5V
+5V
2nd LO
TX-VCO
RX-VCO
LO
+5V
+3V
3.0 V
12.8 MHz
15.3 MHz
5.0 V
5.0 V
• MAIN UNIT (1/4)
*Refer to the PARTS LIST for the value and name of component.

Icom IC-A25C Specifications

General

Purpose	Aviation Service (Air Band)
Operating frequency	118.000 – 136.992 MHz
Display type	LCD
Display diagonal	2.3 \
Battery type	BP-288
Battery life (max)	10.5 h
Battery low indication	Yes
Number of batteries supported	1
Product color	Black
Operating temperature (T-T)	-10 - 60 °C
Number of batteries included	1 pc(s)
Antenna connector type	FA-B02AR

Weight and Dimensions

Depth	31.8 mm
Width	58.9 mm
Height	148.4 mm
Weight	384 g