Kenwood KAC-8401 Service manual
POWER AMPLIFIER
KA C-840 1
SERVICE MANUAL
© 2003-2 PRINTED IN JAPAN
B53-0041-00 (N) 3379
Heat sink
(F01-1728-11)
Dressing panel
(A21-4270-03)
Connecting cord assy
(E30-6144-05)
Accessory
(W01-1606-05)
Panel
(A64-3053-02)
Rear panel
(A84-0347-02)
Screw set
(N99-1587-05)
KAC-8401
ADJUSTMENT
No. ITEM
INPUT OUTPUT RECEIVER ALIGNMENT
SETTINGS SETTINGS SETTINGS POINTS
[1] IDLE CURRENT -
Connect an VR5 (A Lch)
DC voltmeter between
VOLUME : 0
chack land A, B VR7 (B Lch)
(Refer to the PC board) VR8 (B Rch)
2.5mV
DC V oltmeter
+
B Lch
VR7
VR6 (A Rch)
ALIGN FOR FIG.
After Pow er on
2 minutes (a)
2.5mV
BU
GND
PCON
VR8
B Rch
+
Fig. (a)
VR6
A Rch
+
VR5
A Lch
+
Ach Bch
L+
LR+
R-
L+
LR+
R-
2
A B C D E
1
D39
Q29
5
W36
W37
KAC-8401
1
PC BOARD (FOIL SIDE VIEW)
AUDIO UNIT X09-5610-10 A/2 (J74-1513-11)
C111
IDLE CURRENT
: 2.5mV
DC Voltmeter
C209
C109
R119
R117
2
J2
R121
R221
W243
R222
R122
R220
W538
J1
C55
W246
C56
W247
D200
3
A IN B IN OUT
D100
C54
R101
C53
C100
W269
R86
S6
AB/AA HPF/OFF/LPF B HPF/OFF/LPFB.B OFF/ON
W265
W244
4
B ST/NONO
B FREQA FREQ
A ST/MONO SP IN
5
SENS A SENS B
W272
W271
S4
W529
W531
W530
W266
W532
W264
S2
S1
S3
W263
W250
W249
W261W259
W542
W540
R197
R297
C203
R201
R202
C200
R200
W248
R102
R100
C171
W260
W526
R299
W541
R199
C204
W252
C103
R87
C271
W234
C104
W245
C226
C201
C202
C101
C102
VR4
W539
C126
R296
R203
R204
R103
R104
R237
C173
VR2VR1
R138
VR3
R196
R331
R332
R329
D102
R137
C273
R250
R249
R150
R149
C150
W239
R238
W238
W537
W236
S5
6
W528
R315
R316
C306
R308
R312
R314
C40
R307
C39
R311
R313
C305
C211
R217
W199
R218
C37
C250
C205
R205
W221
D201
R206
D101
C106
W229
R330
C307
W230
W235
W232
W237
W535
W534
R135
C117
R133
W536
W228
W231
W227
W527
W233
W222
IC6
58
R309
C303
C212
R120
C206
D202
R106
R108
C118
R136
14
C112
C210
C110
W210
W197
W211
W198
R219
W200
W201
R118
W202
W223
W216
R209
C213
R225
R207
W523W522
C231
17
IC3
814
C232
R226
C214
R208
R210
W224
R109
C105
C113
R107
R125
W521
C131
R105
17
IC1
814
R110
C132
R126
R303
R231
R301
R229
R319
W520
R233
8
R235
C219
C217
R239
W220
W214
R240
C218
C220
R236
R234
R320
C308
8
R230
R232
W533
R302
W518
R140
R142
C120
17
R134
IC2
814
R141
C119
W519
R139
C123
R129
C228
W219
W215
R298
C128
C230
W206
W217
W213
Q218
B
W218
C304
R310
R282
R286
C267
BLch
EE
Q215
R213
C215
R223
W517
R227
R215
R211
R212
R216
W516
C216
R228 R294
R224
R214
C38
C33
R123
C115
R113
R127
R115
R111
R112
W188
C116
R114
R116
W514
R248
IC4
C35
R131
8
C36
R241
W512
C43
C44
C122
R144
R143
WH1
1
W513
IC5
R124
C114
R304
IC7
C50
R198
C301
C223
17
14
R242
R306
C302
3
C224
R146
R132
R194
C34 R128
R305
C42
17
R244
W509
14
W511
R145
C121
17
14
R148
E
W186
W274
R290
BE
W187
W179
W180
R318
W515
W184
W185
R317
C41
R243
W178
C124
W510
C130
Q214
B
E
R287
W167
R130
C32
D34
R295
R195
W181
W183
W174
Q211
W164
W165
W172
W168
W279
Q210
W176
W508
W160
R64
C270
B
E
R61
C23
R65
R323
BLch
VR7
W144
W145
W171
W161
W507
C221
R246
W163
W155
W156
W278
BE
EB
Q33
W173
W169
W149
R245
C222
W170
W143
D33
R275
W158
W166
W152
W154
Q34
W151
W162
W153
R272
R276
R324
Q35
W140
Q209
W137
R273
W130
W150
W277
R68
C24
R281
R285
R277
R283
C265
D35
B
E
R63
C21
R67
R271
W506
EBB
C263
R269
C30
C31
R26
E
D40
Q6
R11
R12
C2
C259
R263
R265
E
W147
W141
Q205
C261
B
W157
Q207
E
B
D31
R257
R267
R251
Q31
E
B
B
W142
W139
Q32
R252
C252
W134
W135
W136
W132
W94
W138
W133
C152
W148
W159
R152
VR8
R274
BRch
W276
Q216
BE
W131
C266
R278
R284
R280
R259
R255
E
R256
Q26
Q217
Q4
BE
R261
W122
W128
R10
W129
W273
W118
W119
W120
W121
D7
W126
R8
D6
EBB
C255
Q201
E
R268
D28
R258
C254
W124
W127
C154
R156
E
R168
B
D22
BRch
EB
Q212
E
C269
B
R279
Q213
R289
B
D18
C15
W100
B
EEB
Q17
W108
Q7
C275
C251
W125
W112
BE
R9
D8
C257
R253
Q208
R254
R154
R158
R84
C264
W109
Q203
B
W113
W114
C253
B
E
E
Q202
B
W123
Q102
EB
Q108
R13
D10
R70
W117
R270
C1
W543
W106
R69
C262
W116
C256
E
B
R27
W103
W105
Q204
C276
C3
W505
R262
C156
W110
C162
W504
C176
R40
C4
E
B
W102
C12
R48
R266
Q206
R264
E
R260
B
C258
Q104
R162
EB EB
Q106
W104
+
D29
C260
C27
W101
Q118
D38
R62
R66
C22
R288
R186
R182
EB
C268
Q36
C13 C14
W98
D19
C16
R44
R41
R43
Q18
C11
C26
Q24
BE
W99
R47
R49
W92
W75
W82
W89
W91
W93
W97
W90
W88
W83
W84
W85
W86
W87
C158
W80
W81
W78
R164
C160
W79
W77
W96
W76W95
W74
R160
R166
BE
D26
R54
R58
C20
W70
R190
BE
EB
C170
Q28
Q114
W73
VR6
W525
Q110
R32
R31
Q9
Q12
Q
Q11
W524
B
E
EBEBE
W39
R35
R33
R34
R36
R37
R38
SDGSDG
Q13
W38
W44
C45
B
W55
D16
R15
D14
Q15
W52
W407
R23
R19
R17
W46
C29
R18
9
C28
W48
W51
R16
C6
D12
W49
R75
R77
C49
D43
R81
C47
R80
R78
BE
Q20
C48
W503
R42
D17
W60
W65
W66
R39
C9
C57
L3
C5
W71
W72
D42
R45
C7
16
R46
R14
D41
R28
W63
W69
D11
R22
R20
IC8
18
R21
R30
Q23
EB
D32
W54
W56
W53
D21
W64
W61
R59
R60
W62
ARch
R174
R170
C166
W67
C164
W68
W58
W59
BE
R172
R176
R322
W57
R180
R178
C153
W50
C151
R151
Q25
Q116
R184
R153
Q101
R155
EB
R157
E
B
D27
EBB
ARch
R188
B
Q112
E
R167
B
Q107
W40
W41
W42
W43
TH3
D24
R52
R56
C18
Q30
B
E
C168
E
Q103
C175
C155
EB
R161
W45
R159
C161
EB
R169
W3
Q117
D25
R53
R57
C19
B
E
R181
R185
7
IDLE CURRENT
: 2.5mV
IDLE CURRENT
: 2.5mV
DC Voltmeter DC Voltmeter
4
JIHGF
3
5
5
KA C-8401
1
X09-5610-10
R32
1
Q10
Q12
11
B
B
E
E
W39
D15
R35
R33
R34
R36
R37
R38
D9
13B
25B
33B
44B
54B
66B
75B
IC Q Address
SDGSDGSDG
R4
ALch
C165
R173
C52
Q1
R29
BE
W19
C169
Q16
L1
L2
W14
W15
C46
BE
BE
Q22
W17
W18
Q8
W11
VR5
W13
Q21
R327
W7
W8
W10
B
Q5
E
EB
R79
C25
W5
R325
W9
W6
W275
R192
Q115
R171
R175
R321
W22
R189
BE
Q113
R179
Q13
W38
W44
524
C45
D39
Q103
C175
C155
EB
R161
R159
C161
EB
R169
W36
W35
Q117
D25
6
R53
18
R57
C19
B
E
R181
Q29
R185
Q14
W20
W21
W34
W406
W26
W404
W12
W23
W24
TH1
W25
C10
W37
R25
Q3
R5
E
B
R6
R50
R24
R7
D4
W29
W33
W31
W27
C157
C159
R165 R163
C163
Q105
W28
R328
W32
R326
W16
W30
Q109
EBEB
EB
W4
W401
R292
R291
R191
W403
C309
W402
R74
R72
78
56
34
12
C192
ALch
D23
R177
R71
W2
R183
W405
R73
C292
D1
W502
R1
D2
C167
Q111
11
10
9
W501
D3
R2
Q2
C191
B
R55
C17
R187
BE
J3
EB
R3
X09 B/2
D5
12
C291
Q27
E
R51
C8
CN2
D13
CN1
31
C51
DC Voltmeter
IDLE CURRENT
: 2.5mV
84E
14F
24G
34F
43C
55F
63C
73C
84F
92E
10 2F
11 2E
12 2E
13 2F
14 2F
15 2E
16 2F
17 2D
18 2D
20 4E
21 4F
22 4F
23 4E
24 4D
25 5E
26 5C
27 6G
28 7D
29 7F
30 6E
31 4C
32 4C
33 1C
Refer to the schematic diagram for the
values of resistors and capacitors.
IC Q Address
34 7C
35 2C
36 7D
101 5E
102 5D
103 5F
104 5D
105 5F
106 5D
107 5E
108 5D
109 6F
110 6D
111 7G
112 7E
113 7G
114 7D
115 6G
116 6E
117 6F
118 6D
201 4C
202 5D
203 4D
204 5D
205 4C
206 4D
207 4C
208 4C
209 2C
210 6C
211 1C
212 7C
213 2D
214 7C
215 2C
216 6C
217 2C
218 6B
2
3
4
5
6
7
5
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