![background image](http://html.mh-extra.com/html/icom/ic-91a/ic-91a_service-manual_612375045.webp)
12 - 2
12-2 MAIN UNIT
VOLTAGE LINE
Explanatory notes
TX LINE
RX LINE
COMMON LINE
J703
to RF
unit J1001
LVIFA
IFA
to LOGIC
unit J401
J702
47P
C768
10P
C767
10P
C766
10P
C765
47P
C764
CK
VCC
DATA
MOD
+5.5V
SQL
PLLDATA
HV
APLLSTB
TXC
REFMOD
IOSTB1
BPLSTB
DASTB1
BPS
UNLK
IOSTB2
TTEMP
IOSTB3
CHG
BTONE
DAFOUT
ATONE
INTPTT
+3V
S-LV
BAF
VOL
BRSSI
DICK
BNOIS
DIUD
ANOIS
CLONE
AAF
INTSP
AFO
EXTMIC
GND
DASTB1
BAGC
IOSTB1
VBUAC
UNLK
AR3C
TTEMP
300M800MC
REFC
APLLSTB
CHG
PLLDATA
T6
DATA
MOD
CK
HV
RFR3
+3V
+5.5V
AAGC
VCO3V
RFB
REF
VCC
MAIN UNIT
470
R406
82P
C111
0.001
C300
100
R455
1K
R55
1.5K
R218
5P
C140
0.001
C235
0.1
C209
1SS364
D202
CD4066BPWR
IC700
1
I/O1
2
O/I1
3
O/I2
4
I/O2
5
CONT2
6
CONT3
7
VSS
8
I/O3
9
O/I3
10
O/I4
11
I/O4
12
CONT4
13
CONT1
14
VDD
0.01
C3
0.001
C601
UNR9115J
Q105
0.1
C206
L301
33N
47
R202
UNR9115J
Q300
0.001
C711
0.1
C131
MA2S728
D100
220
R204
18K
R553
270K
R224
J700
100K
R151
2SC4215
Q200
27P
C306
HVC375B
D352
MA2S728
D204
2P
C468
0.1
C238
0.47
C414
100P
C55
15K
R560
1SS364
D450
1M
R159
0.001
C603
XP1115
Q102
1
2
3
4
5
0.0047
C243
82K
R252
1SS364
D203
0.1
C125
10
R558
0.22U
L201
100P
C211
0.1
C236
100P
C459
12K
R227
82N
L50
180K
R556
0.01
C138
1
C452
CD4094BPWR
IC701
1
STR
2
D
3
CLK
4
Q1
5
Q2
6
Q3
7
Q4
8
GND
9
QS
10
Q’S
11
Q8
12
Q7
13
Q6
14
Q5
15
OE
16
V+
6.8K
R551
100
R222
100K
R500
2SC4215
Q100
0.47U
L453
0.56U
L450
2SC5195
Q301
18K
R554
0.22U
L200
15K
R557
820
R106
47P
C226
1k
R112
0.001
C702
47P
C722
0.001
C501
0.18U
L1
0.001
C651
0.01
C12
47P
C710
47K
R208
XP4315
Q453
1
2
3
4
5
6
0.001
C472
0.47
C227
0.001
C714
180
R52
820
R404
47K
R221
0.1
C557
47P
C406
2.2K
R6
0.1
C256
150
R354
100
R129
XP6501
Q550
1
2
3
4
5
6
0.001
C301
0.001
C650
22K
R509
47K
R158
12K
R228
47K
R207
UNR9115J
Q150
0.001
C360
0.001
C464
2.2K
R559
0.1
C410
0.01
C4
18K
R555
0.001
C600
EP450
1
C135
CD4066BPWR
IC703
1
I/O1
2
O/I1
3
O/I2
4
I/O2
5
CONT2
6
CONT3
7
VSS
8
I/O3
9
O/I3
10
O/I4
11
I/O4
12
CONT4
13
CONT1
14
VDD
0.1
C17
0.22U
L100
68K
R355
0.001
C229
12K
R114
0.0047
C25
1
C558
1.5K
R120
15P
C105
0.01
C10
47P
C307
0.0047
C244
330
R16
0.01
C510
0.01
C59
82K
R153
1
C143
0
R704
6.8K
R201
0.001
C129
10
C302
EP705
UNR9115J
Q204
10K
R250
2SC5195
Q351
EP100
6.8K
R654
1.5K
R210
XP6501
Q104
1
2
3
4
5
6
0.1
C514
0.1
C123
0.015
C553
CD4066BPWR
IC500
1
I/O1
2
O/I1
3
O/I2
4
I/O2
5
CONT2
6
CONT3
7
VSS
8
I/O3
9
O/I3
10
O/I4
11
I/O4
12
CONT4
13
CONT1
14
VDD
J701
EXT MIC
2.2K
R474
1K
R400
5.6K
R405
1k
R203
1
C261
1k
R211
0.1
C561
0.0033
C512
EP401
150
R303
390
R565
0.1
C215
180
R9
0.0015
C153
15K
R233
FL-394
FI1
1
IN
2
OUT
3
GND
4
GND
5
6
68P
C60
270K
R453
150K
R156
47P
C407
0.1
C216
100P
C158
EP701
0.018
C559
47
R350
0.001
C454
270
R8
EP50
4P
C56
1k
R702
UPC2757TB
IC50
1
RFI
2
GND
3
LO
4
PS
5
VCC
6
IFO
220
R104
0.001
C602
0.1
C223
47K
R107
180K
R561
0.1
C157
1SS364
D3
0.1
C156
0.0047
C555
2SB1132
Q602
0.1
C208
TA31136FNG
IC200
1
OSCIN
2
OSCOUT
3
MIXOUT
4
VCC
5
IFIN
6
DEC
7
FILOUT
8
FILIN
9
AFOUT
10
QUAD
11
IFOUT
12
RSSI
13
N-DET
14
N-REC
15
GND
16
MIXIN
0.0047
C26
XP1501
Q601
1
2
3
4
5
UNR9215J
Q101
47P
C141
0.001
C653
HVC375B
D350
330
R18
MA132WK
D351
0.001
C606
0.039
C252
CDBC450CX24
X100
22
C654
SFECV13.35MAS
FI2
I
O
0.01
C554
0.001
C118
1K
R600
1M
R259
1
C144
0.1
C224
82K
R253
330K
R155
0.1
C450
12K
R116
0.01
C113
39P
C13
XP1115
Q604
1
2
3
4
5
330
R706
0
R705
10K
R352
XP1501
Q651
1
2
3
4
5
100
R568
1K
R403
XP1501
Q603
1
2
3
4
5
15P
C305
0.1
C225
0.001
C401
1k
R215
0.1
C239
0.01
C455
EP200
0.01
C203
1
C504
0.0047
C217
0.001
C718
470K
R564
6.8K
R351
2SB1132
Q600
MA2S111
D205
10K
R302
0.01
C473
4.7K
R127
150K
R220
150K
R256
2.2K
R473
0.1
C136
0.001
C503
12K
R115
47
R300
47P
C408
2.7K
R703
0.001
C303
7P
C5
0.001
C132
0.001
C712
100P
C112
47K
R209
22
C604
2SB1132
Q652
0.001
C607
0.22
C400
0.001
C451
1M
R650
0.01
C102
0.0047
C474
0.22U
L103
1SS364
D102
0.01
C228
TP76D96
S702
CHASSIS
C
A
B
470
R652
12P
C356
6.8K
R101
0.0015
C513
22K
R508
4.7K
R131
0.01
C15
0.001
C259
0.01
C9
0.001
C104
2.2K
R11
1
C563
2SC4215
Q450
1K
R402
FL-335
FI50
1
IN
2
OUT
3
GND
4
GND
5
6
0.001
C713
0.001
C352
TA31136FNG
IC100
1
OSCIN
2
OSCOUT
3
MIXOUT
4
VCC
5
IFIN
6
DEC
7
FILOUT
8
FILIN
9
AFOUT
10
QUAD
11
IFOUT
12
RSSI
13
N-DET
14
N-REC
15
GND
16
MIXIN
UNR9211J
Q650
1k
R304
0.0015
C250
56
R410
2SC4081
Q201
0.1
C154
68K
R157
18P
C357
NJM12904V
IC250
1
2
3
4
5
6
7
8
0.001
C701
47P
C205
330
R24
6.8K
R301
0.0033
C150
0.0033
C506
27P
C247
10
C214
150K
R123
4.7K
R225
4.7K
R305
0.47U
L452
2.2K
R7
0.001
C416
0.1
C137
12K
R118
470
R459
82P
C207
1
C550
UNR9115J
Q205
2.2K
R19
0.1
C237
47P
C757
47P
C752
47P
C751
47P
C773
47P
C775
47P
C777
47P
C779
47P
C781
47P
C789
47P
C790
0.001
C210
0.001
C159
47K
R122
12K
R119
0.001
C231
150
R51
4P
C58
47P
C466
0.01
C128
0.1
C241
47P
C409
0.001
C700
100P
C258
68K
R257
0.033
C117
0.001
C359
R562
1M
15K
R451
1K
R601
0.01
C54
7P
C7
1
C233
0.001
C457
82K
R254
UNR9115J
Q250
0.001
C52
0.001
C133
330K
R255
0.22U
L102
22
C609
0.001
C703
10K
R651
150K
R452
0.0022
C556
0.56U
L451
12K
R232
0.001
C502
1K
R700
2.2K
R10
47P
C708
1SV325
D300
CDBC450CX24
X200
0
R23
1K
R121
0.47
C127
12K
R229
2SC5006
Q353
NJM12904V
IC150
1
2
3
4
5
6
7
8
0.001
C705
100P
C126
0
R251
100K
R15
1k
R356
15K
R130
1
C262
LQW1608A15NG00
L351
10K
R552
10K
R653
27P
C245
10K
R132
0.1
C116
1SS364
D2
2P
C248
0.01
C507
15K
R200
82K
R457
2.2K
R550
EP704
2SC4081
Q552
0.01
C456
2.2K
R472
0.001
C719
0.001
C717
82K
R152
0.001
C106
12K
R230
12P
C467
0.1
C562
0.0015
C253
0.001
C716
0.1
C508
2.7K
R566
47K
R219
330K
R223
47
R102
0.01
C232
NJM12904V
IC501
1
2
3
4
5
6
7
8
220K
R471
100K
R506
UNR9115J
Q350
UNR9215J
Q500
1
C155
47P
C709
0.001
C404
0.001
C403
47P
C707
2SC4215
Q452
0.001
C706
0.001
C350
10P
C6
0.0047
C475
12K
R231R231
0.01
C213
10K
R150
0.1
C234
1k
R501
0.1
C124
47K
R258
XP6501
Q103
1
2
3
4
5
6
12K
R503
MA2S728
D200
47P
C139
0.001
C605
1SS364
D103
0.01
C465
0.001
C351
0.001
C204
XP6501
Q202
1
2
3
4
5
6
2SC4215
Q451
MA2S728
D451
0.0047
C24
XP6501
Q203
1
2
3
4
5
6
10K
R602
1k
R117
0.018
1.5K
R108
4.7
C411
0.1
C16
CD4094BPWR
IC702
1
STR
2
D
3
CLK
4
Q1
5
Q2
6
Q3
7
Q4
8
GND
9
QS
10
Q’S
11
Q8
12
Q7
13
Q6
14
Q5
15
OE
16
V+
0.039
C152
0.01
C8
MA2S728
D104
0.001
C608
HVC376B
D301
100P
C142
15K
R100
10
C114
82K
R154
0.1
C560
0.001
C652
680K
R504
1
C255
330P
C151
0.001
C715
0.0047
C242
0.22
C402
68P
C50
5P
C246
18P
C57
1K
R458
15P
C355
0.1
C254
0.001
C160
1K
R401
1K
R454
0.01
C551
0.01
C405
0.01
C458
68K
R456
0.1
C412
470
R470
0.1
C500
100K
R460
0.001
C218
MA2S111
D105
0.1
C257
0.033
C212
10K
R306
0.0047
C29
220K
R505
0.22U
L202
47P
C721
EP400
0.01
C134
0.001
C511
0.1
C115
22K
R507
0.1
C240
0.001
C453
0.01
C505
0.001
C704
0.001
C260
1K
R217
CR-826
X450
1
VCON
2
GND
3
OUT
4
VCC
12U
L101
390P
C109
680
R105
HSB88AS
D10
390K
R450
120K
R113
150K
R111
0.001
C120
56K
R109
0.001
C119
120K
R216
0.001
C221
0.001
C222
150K
R214
0.001
C220
56K
R212
0.001
C219
0.1
C509
CFWKA450KHFA
FI201
I
O
100P
C108
2SC4081
Q1
2SC5006
Q2
100K
R17
470K
R124
33K
R126
27K
R125
2.7K
R133
22
C130
22
C230
56
R14
47P
C723
15P
C462
3P
C461
4P
C463
8P
C469
4P
C470
220P
C730
10P
C61
220P
C731
220P
C732
SKHLLFA010
S700
SKHLLFA010
S701
CFWM450E
FI100
I
O
CFWM450E
FI200
I
O
1.2K
R205
1k
R206
39K
R234
UNR9215J
Q206
0.001
C263
MB15E03SLPFV1
IC400
1
OSCI
2
OSCO
3
VP
4
VCC
5
DO
6
GND
7
XFIN
8
FIN
9
CLK
10
DAT
11
LE
12
PS
13
ZC
14
L/F
15
P
16
R
470P
C121
470P
C122
100
R701
18P
C460
15K
R110
CP1
33K
R235
5P
C51
5P
C308
5P
C358
47P
C720
27K
R213
EP702
47P
C309
0.001
C353
100P
C14
270
R353
VBVCOC
UBVCOC
WFM
ACT
BRSSI
REFC
REFMOD
CLONE
MAINR3A
MAINR3B
AR3C
BR3C
ANOIS
BNOIS
CK
PLLD
A
T
A
BPLSTB
BPS
WFM
VBUAC
UBVCOC
IOSTB2
VBVCOC
AAM
BAM
300M800MC
R3C
AR3C
BR3C
IOSTB3
DATA
CK
ACT
BCT
DICK
DIUD
MAINR3A
BAGC
BTONE
ATONE
BCT
S-LV
AR3C
AAM
MAINR3A
AAM
BAM
AAF
BAF
R3C
+3V
RFR3
ACT
EXTMIC
MAINR3B
TXC
+3V
D
ASTB1
DA
T
A
CK
+5.5V
APLLSTB
BPLSTB
IOSTB2
BT
ONE
AFO
VCC
VCC
AAFS
W/N
DAFS
+5.5V
PLLD
A
T
A
BAM
+3V
MAINR3A
MAINR3B
W/N
DAFOUT
INTPTT
SQL
MAINR3
IFC
T6
LV
INTSP
MAINR3
VO
L
AFO
B BAND VCO
EXT SP
VOL/DIA
C552
OFF: 0.50V
A TONE ON: 3.25V
TX: 0V
A AM RX: 3.26V
B FM RX: 0V
A FM RX: 0V
B FM-N RX: 3.22V
A FM RX: 0V
B FM RX: 0V
TX: 0V
B RX: 3.24V
A RX: 0V
TX: 0V
OFF: 0V
B TONE ON: 3.21V
TX: 0.46V
A RX: 2.97V
B RX: 0.16V
B AM RX: 3.23V
B FM RX: 0V
A FM RX: 0V
TX: 0V
B RX: 2.93V
A RX: 0V
TX: 0V
TX: 0.46V
A FM RX: 2.42V
B FM RX: 2.41V
A WFM RX: 0V
TX: 0V
A WFM RX: 3.35V
B FM RX: 0V
A FM RX: 0V
TX: 0V
A WFM RX: 3.35V
B FM RX: 0V
A FM RX: 0V
TX: 0V
A WFM RX: 3.31V
B FM RX: 3.33V
A FM RX: 0V
A RX: 0V
TX: 0V
B RX: 3.25V
RX: 2.51V
TX: 0.40V
A RX: 0V
B RX: 0V
TX: 2.30V
B 145
RX: 2.91V
TX: 0V
B 145
RX: 0.92V
TX: 0V
B 435
RX: 3.02V
TX: 0V
B 435
RX: 1.05V
TX: 0V
RX: 2.89V
3.34V
5.53V
1.01V
TX: 0.42V
TX: 0.45V
A RX: 3.18V
B RX: 0.19V
TX: 0V
A RX: 0.44V
B RX: 0V
B RX: 2.08V
A RX: 0.63V
TX: 0V
B RX: 0.25V
A RX: 0V
TX: 0V
B RX: 3.24V
A RX: 0V
TX: 0V
B RX: 2.40V
A RX: 2.44V
TX: 0.47V
TX: 0V
A RX: 3.28V
B RX: 0V
B RX: 3.25V
A RX: 0V
TX: 0V
TX: 5.84V
RX: 0V
TX: 0.47V
RX: 3.39V
7.37V
TX: 0V
RX: 3.43V
B RX: 2.91V
A RX: 0V
TX: 2.93V