Kenwood KACX-40 Service manual
POWER AMPLIFIER
This product uses Lead Free solder.
KA C-X40
SERVICE MANUAL
Dressing Panel
(A21-6571-01) : K type
(A21-6572-01) : M type
© 2006-12 PRINTED IN JAPAN
B53-0485-00 (N) 719
K type only
Fuse (25A)
(F52-0014-05)
Accessories
(W01-1606-05)
Screw set
(N99-1794-05)
KA C-X40
AL
AR
BL
LINE IN (0.2-5V)
IC2
ISO-AMP
IC1
ISO-AMP
IC3,4
ISO-AMP
IC3,4
ISO-AMPBR
L
(X08-433)
ST/
MONO
SEL
ST/ A/AB
MONO
SEL
BLOCK DIAGRAM
IC1
H.P.F
(40-200Hz)
SEL
IC1
H.P.F
(40-200Hz)
IC4
L.P.F
(40-200Hz)
H.P.F SEL.
L.P.F SEL.
SENS.
VOL
IC6
IC6
H.P.F
(40-200Hz)
H.P.F
(40-200Hz)
IC9
IC9
Q280,283
ATT
ATT
H.P.F SEL.
Q282,284
IC7
BASS
BOOST
IC8
BASS
BOOST
Q241
Q242
MUTE
MUTE
SENS.
VOL
POWER AMP
POWER AMP
IC10
IC10
AL
AR
(INV)
SP OUTPUT
LINE IN
R
Q1,2,15-17
15V
AVR
Q215-218,
415-418
OVERLOAD
DET
D5,6
B
Q443
MUTE
Q444Q482,484
MUTE
Q611-614
DC-OFFSET
DET
IC5
Q605,606
POWER
ON/OFF
DC/DC
CON
Q3-14
POWER
INDI.
TH601-605
THERMAL
DET
LC FILTER
Q684,685
FAN AVRFAN
P-CON
BATT.
GND
Q481,483
ATT
ATT
COMPONENTS DESCRIPTION
POWER AMP
POWER AMP
BL
BR
(INV)
70W x 4ch / 4
100W x 4ch /2
SP OUTPUT
● PREAMPLIFIER UNIT (X08-4330-10)
Ref. No. Application / Function Operation / Condition / Compatibility
IC1 HPS HPF at side A 40-200Hz
IC4 LPF LPF at side B 40-200Hz
IC6 HPF HPF at side B 40-200Hz
IC7~8 BASS_BOOST BASS_BOOST at side B 40-100Hz_0-18dB
IC9 X08 signal output Lch output buffer at A side, Rch phase inversion, and output buffer
IC10 X08 signal output Lch output buffer at B side, Rch phase inversion, and output buffer
2
KA C-X40
COMPONENTS DESCRIPTION
● AUDIO UNIT (X09-8580-10)
Ref. No. Application / Function Operation / Condition / Compatibility
IC1 Rch input buffer at side A and isolation
IC2 Lch input buffer at side A and isolation
IC3 L/Rch input buffer at side B Input signal amplification (+6dB) at side B
IC4 L/Rch isolation at side B Noise reduction in input signal transmission quality at side B
IC5 DC/DC control Controlled by P-CON & protection circuit
IC6 ATT Detects inside temperature and makes the necessary ATT.
Q1,15,17 +15VAVR Operation while P-CON is turned on.
Q2,16 -15VAVR Operation while P-CON is turned on.
Q3~8 DC/DC Controlled by IC5.
Q9~12 DC/DC driver Controlled by IC5.
Q13,14 DC/DC delay start circuit Delays the start of DC/DC when P-CON is turned on.
Q201~204,401~404 ACLASS initial stage Voltage amplification of small signal
Q205~210,407~410 ACLASS second stage Voltage amplification of small signal
Q211,212,411,412 Constant current circuit Makes current in ACLASS initial stage constant.
Q215,216,415,416 Over current limiter Operation under the over current condition
Q217,218,417,418,610 Over current protection Operation under the over current condition
Q220,222,223,225,423,
Q425,426,428
Q241,242,443,444 AUDIO MUTE Controlled by Q603.
Q280,282,283,290,
Q481~484 changes in temperature (TH601-605)
Q601~606 P-CON control Operates when P-CON is turned on/off.
Q611~614 DC protection Operates when DC is detected in the SP output.
Q615~618 POP MUTE Operation while P-CON is turned on.
Q619,620 LED driver Operation while P-CON is turned on.
Q621 Power switch for thermistor Operation while P-CON is turned on.
Q684,685 FAN AVR Operation while P-CON is turned on.
AMP final stage Current amplification of small signal
ATT
Rch input signal amplification (+6dB) and noise reduction in transmission
quality at side A
Lch input signal amplification (+6dB) and noise reduction in transmission
quality at side A
Controlled by IC6. Takes the level of -1.5dB or 3dB in response to
NO. ITEM
1
IDEL VR2 (A Rch) voltmeter between
CURRENT VR3 (B Lch) check land
ADJUSTMENT
ALIGNMENT
POINT
VR1 (A Lch) Connect a DC
VR4 (B Rch) (Refer to PC BOARD)
METHOD ALIGN FOR NOTE
2.0mV After Power on 5minutes
3
A B C D E
W59
Q
W
KAC-X40
1
2
3
4
5
6
PC BOARD (FOIL SIDE VIEW)
B Lch 2.0mV
AUDIO UNIT
B Rch 2.0mV
DC voltmeter
C416
D404
Q416
Q418
D408
W203
W198
22
21
CN1
2
1
W200
W201
X09-8580-10 A/2 (J76-0344-11)
R434
R458
BE
R438
W700
R430
C420
BE
C422
R432
R440
W697
R454
VR4
R436
W696
W202
R198
C128
C228
R196
R396
W191
C156
C126
C326
C227
R195
W190
C127
C356
W181
W182
W189
R395
C350
C107
W188 W187
D302
W699
R194
W186
R394
W698
R398
W199
C316
W193
W194
W195
W196
W197
C115
C116
W192
C315
C150
Q424
BK
E
W695
IDEL BR
R450
Q426
E
AB
W180
W185
C305
R370
IC3
58
R372
D301
C306
R303
C301 C302
C303
Q415
Q417
W183
W175
A
ECB
CE
TH605
K
B
R656
R307
R309
R311
R305
14
R306
R312
R308
R310
R304
R301
W176
J1
W694
D403
W174
R446
R302
W184
W169
W692
W693
D618
W179
W172
R448
E
W171
C333
C334
C304
BE
B
D461
W173
W177
W170
C313
R323
41
IC4
58
C314
R324
R101
D405
W168
R325
C331
C332
R437
R429
C419
R431
C421
R439
BE
Q610
W167
Q484
R326
R617
D496
C230
Q425
R625
KBCE
R435
C606
R457
C415
D463
D458
W158
C911
W704
Q412
R442
R490
R492
R484
Q482
C424
R480
R444
W753
C229
C338
R314
R313
C337
W754
R104
R103
C101
C102
R102
W166
C103
DC voltmeter
W686
AB
E
TH604
R629
W161
R416
W157
Q410
R408
Q406
R422
Q408
R424
R414
C410
Q404
C406
R410
BE
R452
C318
C402
W162
W164
W155
W163
W165
D430
R465
R466
R488
R427
R428
Q443
Q444
W156
W690
W687
W154
W160
W688
W691
D102
C721
C124
C324
C722
W153
C104
R722
C408
R721
R447
R464
C418
Q402
C404
W152
R486
R401
R418
C412
C414
C464
R412
R468
R489
D101
R459
EB
BE
BE
BE
BE
R404
D495
R481
Q481
C423
W683
R111
D100
D300
C413
C417
R491
R909
C100
C300
R910
W144
W146
R407
C411
R474
C463
R443
IDEL BL
R449
W148
W684
W145
R417
R473
R405R406
R411
Q401
R403
W685
Q483
R112
R170
R105
R467
W682
R106
R172
R453
BE
EB
R455
Q407
EB
R423
C407
R463
EB
R409
EB
C403
D296
Q284
41
C113
C133
R109
C114
R445
C317
R244
IC2
R123
C2
Q423
BK
E
ECB
VR3
W147
W149
W150
R260
C908
W140
Q409
D462
Q405
R419R420
D457
W755
R413
C409
C910
W703
Q403
C405
Q411
BE
R451
W151
C401
W136
W143
R290
R287
R284
R292
Q282
R280
C226
R107
C105
85
R125
C129
C131
C132
R110
C134
R124
R126
41
IC1
85
C106
R108
C909
W139
R266
Q242
W751
W138
R441
D229
R227
R228
C130
W130
D460
D211
D210
C34
C33
W680
W137
W134W135
R113
W752
C3
A
R433
W129
D459
C261
R265
Q241
W679
W133
R285
R201
W131
R114
W132
C5
C4
C930
Q2
EB EB
W115
C260
R261
W122
C906
C907
W123
D261
Q206
W677
R220
D152
R224
W124
R214
C210
C913
Q204
W702
D254
C206
R210
R256
W678
W676
W126
BE
Q212
C202
R242
D295
W675
R289
R291
R282
BEBEBEBEBEBEBEBEBEBEBEBE
Q283
C225
R243
Q280
R646
R647
R659
C616
R425
BE
R602
BE
Q620
R601
14
W245
R918
R222
C208
R650
W673
R916
D253
R216
Q210
C619
R627
R660
Q619
Q684
R471
D11
R912
R208
Q208
W117
C118
C605
BE
R2
R915
R264
R684
EB
C214
R206
W120
R218
C212
C264
C218
C204
W121
Q685
W204
Q16
EB
BE
BE
BE
BE
R268
R917
W118
W119
R683
EB
W106
W107
W108
W109
C211
C213
C217
R204
W672
W104
W102
R207
R274
R211R212
Q202
W116
C682
R986
C681
R682
R681
W103
R217
C263
W114
C12
R913
D3
Q17
W112
EB
R273
R205
Q201
R203
W113
J8
R911
W105
W111
R685
C929
R267
W670
EB
EB
C207
EB
EB
W110
W671
R221
Q207
R223
R263
Q203
R209
C203
R618
D911
C450C451
R914
R215
Q209
Q205
R213
C205
R255
C117
W243
SDG
C209
C201
W244
BE
R1
R470
Q15
W100
W96
R219
D251
C912
Q211
W101
W701
Q1
D4
D260
W88
W90
W97
W98
BE
W242
D619
W34
W35
C223
R252
C216
W92
W94
R253
Q219
R257
R241
R225
W93
W85
D620
W95
R236
Q222
AB
KBCE
W83
W87
BE
R254
D207
D209
W78
W80
W86
W89
W81
W84
W91
W205
A Rch 2.0mV
DC voltmeter
Q218
D206
BE
C222
R232
R240
W665
W668
W666
E
R262
R248
W667
W82
W76
C7
W77
R621
BEBEBE
Q612
W75
W74
W79
R271
C251
Q216
W73
W72
W212
W64
W65
BE
C220
R230
IDEL AR
R250
R620
Q611
W71
W70
R623
D204
R238
W69
W68
VR2
R622
Q613
W66
P1
R635
D255
W60
B
E
E
R246
W63
R637
C609
R636
C610
B
R634
C607
R633
W62
W67
W61
W2
W2
W33
D107
7
4
JIHGF
Q613
R622
KAC-X40
1
V
r
D255
ECB
VR2
R246
R635
R637
C609
R636
B
R634
C607
R633
W62
W67
W61
W66
P1
W33
W60
Q220
BK
E
TH603
W58
W63
C610
D614
BE
Q614
W59
W660
W662
W663
W664
W57
W206
W207
A
R665
D613
R632
C250
W54
C608
R234
R673
W659
Q617
R661
Q615
Q601
R270
A Lch 2.0mV
DC voltmeter
IDEL AL
Q215
Q217
D205
D617
R235
W49
W50
W661
C215
R251
C6
C604
BE
BE
Q618
R663
R662
R664
BEBE
Q616
W55
W602
BE
C601
W601
W56
D605
R613
W46
W47
W52
R605
R604
R666
R667
R628
W53
Q621
W48
C617
R672
R610
R609
R669
W51
W40
W41
Q225
AB
W657
KBCE
TH602
R675
W44
W42
W45
D616
R668
W43
R670
R671
W213
W655
W658
W656
Q603
BE
BE
R603
R606
R607
C602
D604
R611
Q606
BE BE
D606
R614
C603
R616
J3
R5
W39
D602
R615
W208
BE
W654
E
Q602
R608
D603
R612
R3
R4
C8 C9
EB
D607
R644
R676
W37
W38
Q605
W502
W653
R6
R643
R624
C618
R651 R653
C620
W32
Q604
W36
R239
R259
BE
C221
R231
W651
W652
R247
85
IC6
41
R649
W29
W31
W30
L3
R229
C219
R245
W603
D7
BE
R237
W28
R648
W27
D203
R249
W705
BK
E
ECB
Q223
D609
R642
W26
W234
W235
W233
VR1
A
W25
L2
C1
W232
W241
W24
R233
W231
W240
D6
W19
W17
W18
W20
W218
W219
W221
W220
W223
W222
TH601
W224
W225
C11
W22
W21
W650
W23
W504
W228
W229
W230
W239
R32
W227
L1
W238
D5
W15
W16
W216
W215
W217
W503
Q3
Q5
W8
Q7
Q6
Q4
Q8
CN3
12
SDGSDGSDGSDGSDGSDG
R33
R35
R7
R37
R8
R34
R36
R38
W209
D1
W7
C32
W10
W11
W12
W14
W13
W210
W211
C10
W226
W236
W237
W501
X09 B/2
WH1
13
C600
D600
RED
BE
Q9
R11
BE
R13
BE
Q10
Q11
Q12
W6
R15
R16
BE
BE
R17
R20
R14
BE
W214
W3
16 9
W5
R23
R18
W4
R19
Q13
W2
Q14
D10
D9
IC5
81
R21
D8
R25
C17
R22
R24
C15
C16
W1
C14
R9
R10
R12
C611
R674
C13
D2
X09-8580-10
Ref. No.
Address
IC1 6C
IC2 6C
IC3 6B
IC4 6B
IC5 5I
IC6 4G
Q1 2D
Q2 2D
Q3 3H
Q4 4H
Q5 3H
Q6 4H
Q7 4H
Q8 5H
Q9 4I
Q10 4I
Q11 4I
Q12 4I
Q13 4I
Q14 4I
Q15 2D
Q16 2D
Q17 3D
Q201 4D
Q202 4D
Q203 4D
Q204 4D
Q205 3D
Q206 3D
Q207 4D
Q208 4D
Q209 3D
Q210 3D
Q211 4D
Q212 4D
Q215 2G
Q216 2E
Q217 2G
Q218 2E
Q220 2F
Q222 2E
Q223 3G
Q225 2F
Q241 5D
Q242 5C
Q280 5D
Q282 5C
Ref. No.
Address
Q284 5C
Q401 4C
Q402 4C
Q403 4C
Q404 4C
Q405 3C
Q406 3C
Q407 4C
Q408 4C
Q409 3C
Q410 3C
Q411 4C
Q412 4C
Q415 2B
Q416 4A
Q417 2B
Q418 4A
Q423 2C
Q424 4B
Q425 2C
Q426 4B
Q443 5C
Q444 5C
Q481 5C
Q482 5C
Q483 5C
Q484 5B
Q601 5F
Q602 5F
Q603 5F
Q604 5G
Q605 6F
Q606 6F
Q610 3B
Q611 4E
Q612 4E
Q613 4E
Q614 4F
Q615 4F
Q616 5F
Q617 4F
Q618 4F
Q619 5D
Q620 6D
Q621 5F
Q684 6D
Q685 6D
2
3
4
5
6
Q283 5D
Refer to the schematic diagram for the values of resistors and capacitors.
7
5
K L M N O
KAC-X40
1
PC BOARD (COMPONENT SIDE VIEW)
PREAMPLIFIER UNIT X08-4330-10 (J76-0352-12)
CN1
R103
C11
C9
C20
C19
C10
R112
R109
41
121
R204
R248
R203
OP SEL
S3
HPF OFF
FIL SEL
S6
INPUT SEL
S4
MONO ST
OP SEL
S1
ON OFF
HPF
S2
C1
IC1
58
C104
R104
C2
R25
R13
R23
R11
R15
R27
R26
R14
R24
R12
R108
R102
ABA
C102
STMONO
LPF
R110
Ach Bch
C106
X08-4330-10
Ref. No. Address
IC1 5N
IC4 4L
IC6 3L
IC7 5L
IC8 6L
IC9 6L
IC10 3L
22 2
2
C251
C34
R255
W3
C32
C233
W4
R249
C228
R251
C38
RED
C23
C17
R246
C211
R219
R225
C209
C207
R221
C4
R202
R201
C301
R304
R303
R301
C6
C221
R21
C41
C45
R237
R229
C47
C213
C222
C220
C46
R238
R29
R30
R230
C214
C109
R1
C29
W1
C113
R125
R121
C27
R123
D1
C35
R119
R113
3
CN3
4
5
6
C18
IC10
411258
R227
IC6
41
IC4
41
C303
C13
C43
C219
R239
IC7
R235
41
C15
C42
C44
R22
R240
IC8
R236
41
C48
C16
C26
C25
1
IC9
4
C31
R226
C208
58
R222
C5
58
C306
R308
R233
C215
R231
58
C14
R234
C216
R232
58
C110
85
R116
C36
C37
R247
C3
R305
R30
R306
W2
C108
R253
R245
C304
C28
C252
C210
C307
C218
R115
R220
C217
C30
C114
R122
C33
C234
R250
R228
C212
R310
Bch
Ach
R4
R52
R51
C7
SENSHPF
LPFHPF SENS BASS FREQ. BASS BOST
VR2VR1 VR8 VR3VR5 VR6 VR4
C8
R117
R118
C103
R101
R111
R3
200mV5V40Hz 200Hz0dB 18dB5V 200mV200Hz 100Hz40Hz
R243
R244
40Hz 200Hz
C105
R107
C101
40Hz
1
3
CN5
CN4
7
CN2
1
2
Refer to the schematic diagram for the values of
resistors and capacitors.
6
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