Kenwood KAC-6402 Service manual
POWER AMPLIFIER
Accessory
(W01-1606-05)
190mm
Screw set
(N99-1587-05)
Fuse
(F52-0014-05)
Connecting cord assy
(E30-6144-05)
4/3/2channel
Power Amplifier
Powe
Amplifie
MAXIMUMPOWER
4/3/2channel
KAC-6402
(E type,M type)
KAC-6402
(K type)
KAC-6402
SERVICE MANUAL
© 2005-5 PRINTED IN JAPAN
B53-0285-00 (N) 1708
This product uses Lead Free solder.
KAC-6402
BLOCK DIAGRAM
LINE IN
AL
LINE IN
AR AMPLIFIER
LINE IN
BL LPF+6dB
LINE IN
BR
SPEAKER
INPUT
ISOLATION
AMPLIFIER
ISOLATION
ISOLATION
AMPLIFIER
ISOLATION
AMPLIFIER
+6dB 0dB +29.5dB
ST/MONO
ST/MONO
A-AB
Ach
INPUT
GAIN
CONT.
Bch
INPUT
GAIN
CONT.
15V
AVR
THERMAL
PROTECTION PROTECTION
+1
FREQ. CONT.
-1
+1
FREQ. CONT.
-1
HPF
LPF+6dB
HPF
LPF+6dB
HPF
HPF
LPF+6dB
DC/DC
CONVERTER
POWER
AMPLIFIER
POWER
AMPLIFIER
MUTE
POWER
AMPLIFIER
POWER
AMPLIFIER
DC DETECT AND
OVER ROAD PROTECTION
P CON CIRCUIT P CON
OVER VOLTA GE
SPEAKER
OUT AL
SPEAKER
OUT AR
SPEAKER
OUT BL
SPEAKER
OUT BR
BATTERY
COMPONENTS DESCRIPTION
● AUDIO UNIT (X09-5890-10)
Ref. No. Application / Function Operation / Condition / Compatibility
IC1,3 Buffer amplifier Lowers impedance and amplify by 6dB
IC2,4 Isolation amplifier Reduces common mode noise
IC5,9 Buffer amplifier Rch operates as reverse amplifier
IC6,10 Reverse buffer amplifier Reverse amplifier operation of 6dB
IC7,8,11,12 LPF/HPF LPF and HPF with variable cut off
IC13 DC-DC converter Oscillation and control of DC-DC converter
Q3,4 Constant voltage power supply Constant voltage control of ±15V
Q5,6 DC-DC converter Switching FET
Q7,8,9,10 DC-DC converter Gate driver for Q5,6
Q11,12 DC-DC converter ON/OFF of IC13 output
Q101,102,201,202 Input mute circuit Shock noise absorption at power ON/OFF
Q103~106,203~206 Power amplifier First step differential absorption
Q107~110,207~210 Power amplifier Second step differential absorption
Q111,112,211,212 Power amplifier Second step current mirror load
Q113,114,213,214 Power amplifier Power amplification circuit bias temperature compensation
Q115~118,215~218 Power amplifier Excess current detection
Q119~122,219~222 Power amplifier Power amplification step darlington driver
Q123~126,223~226 Power amplifier Power amplification step darlington output transistor
Q601 B-class step mute Mute signal generation circuit: Normally ON
Q602 Mute circuit Mute signal generation circuit: Normally OFF
Q603 Input mute Mute signal generation circuit: Normally OFF
Q604 Power ON/OFF Primary power supply control transistor: Normally ON
Q605 Power ON/OFF Power control circuit
Q606 Power ON/OFF
Q610 Excess current detection Goes ON when detecting excess current and turns OFF DC-DC converter
Q611,612 DC output voltage detection Goes ON when detecting DC output voltage from power amplifier
Excess voltage protection circuit: Goes OFF when primary input voltage of 16V or less
2
KAC-6402
COMPONENTS DESCRIPTION
Ref. No. Application / Function Operation / Condition / Compatibility
Q613,614 DC output voltage detection Latch circuit at DC detection
Q615,616 B-class step mute transistor Circuit for turning OFF input of power amplification step
Q617,618 B-class step mute transistor Driver for Q615,616: Normally ON
D1
D2,3 AVR reference voltage Control Q3,4 by Zenner voltage generated at D2,3
D4,5 Secondary power supply rectifier
D6~9 Switching Reverse flow prevention
D22,201,101,102 Temperature compensation Makes 2nd step deferential transistor ∆Vbe current constant
D32~37 Static protection Prevents ope amp destruction by static
D103,104,203,204 Current mirror 2nd step deferential amplifier current mirror load
D105,106,205,206 B-class step mute Reverse flow prevention
D107~110,207~210 Excess current detection Reverse flow prevention
D229,430 Input mute Reverse flow prevention of signal current
D601 LED control D610 power indicator control
D602,603 Mute control Reverse flow prevention
D604 AVR for mute 10V
D605 Power control Reverse flow prevention
D606
D607 Power control Level shift
Reverse connection protection
for primary power supply
Primary power supply excess
voltage detectoin
Melts off fuse when primary power supply is inversely connected
Level shift
ADJUSTMENT
No. Item Alignment point Method Align for Note
VR5 (ALch)
1
IDLE VR6 (ARch) Connect a DC voltmeter
CURRENT VR7 (BLch) between emitter resister 5 minutes
2.5mV
VR8 (BRch)
Q226 Q224 Q225 Q223
BRch 2.5mV
DC voltmeter
ARch 2.5mV
DC voltmeter
R456
BR
VR8
VR6
AR
Q124 Q126 Q123 Q125
R455
BL
VR7
VR5
AL
R255R256
BLch 2.5mV
DC voltmeter
ALch 2.5mV
DC voltmeter
After Power on
3
A B C D E
R209
D
D
Q109
KAC-6402
1
PC BOARD (FOIL SIDE VIEW)
AUDIO UNIT
X09-5890-10
(J76-0087-11)
2
3
4
5
R607
D603
R616
D605
R614
D607
6
7
Refer to the schematic diagram for the values of
resistors and capacitors.
R606
BE
BE
J9
W156
BE
W164
R609
R610
R611
Q606
11109
W421
W165
R608
Q602
D604
R612
Q605
R613
D1
L3
TH1
W601
C1
C15
W180
7
5
3
1
C602
R615
D606
W181
R603
D602
Q604
8
6
W160
4
2
R604
C603
Q7
W419
W420
W182
P1
W161
W163
R458
R258
C424
C224
Q601
BE
R605
B
E
Q603
D601
EB
R602
W162
SDG SDG
Q6
W178
W179
L2
R10
R12
R13
Q8
BEBE
BE
Q9
W417
R14
BE
Q11
D6
Q12
C423
C223
R457
R257
W158
C601
W157
R633
W155
C607
Q614
C610
D614
R618
BE
W153
BE
R637
C609
R11
R636
W154
BE
W418
R634
BE
W171
W177
Q10
R15
W147
W148
W149
W150
W151
W145
W152
Q613
BE BE
Q611
W170
R9
C14
W143
W146
D613
C606
R632
Q5
C9
R8
W137
W144
W139
Q612
R635
R24
W142
W140
W141
W135
BE
C13
R629
Q610
W172
W173
R22
IC13
W166
W167
R617
R25
W136
R621
R19
R620
169
W416
R623
C608
R23
18
R16
R622
W138
W174
R662
Q616
R668
W415
C12
W124
BE
D4
W175
R17
D9
W120
Q618
BE
R667
W123
W131
W112
R7
C8
W130
W176
C10
D8
R27
R21
D7
C11
R26
W134
W413
W414
W132
W133
W128
W129
W411
W412
R669
D616
Q617
BE
R665
R666
R671
BE
R661
C617
R664
R670
X09-5890-10
Ref. No. Address
IC1 3I
IC2 3H
IC3 2I
IC4 2H
IC5 3I
IC6 3I
IC7 3H
R18
W115
W116
W117
W118
Q615
C7
W114
W410
W121
W122
W119
R663
W125
W113
W126
W127
D5
W409
W110
W111
W408
R2
R1
Q223
E
B
R449
C419
R453
C6
W98
W95
W97
W103
W104
W108
W106
W107
W101
W102
W105
W109
Q121
R247
Q125
Ref. No. Address
IC8 3H
IC9 4I
IC10 4I
IC11 4H
IC12 4H
IC13 4C
Q3 6I
BE
Q219
R439
EB
Q215
W96
W99
W100
W77
BE
R237
E
Ref. No. Address
Q10 3C
Q11 4B
Q12 4C
Q101 4F
Q102 4F
Q213
BE
R429
R445
W405
E
C907
R443
W403
R435
W93
W404
W91
D207
W86
D206
W87
W88
W89
W81
W396
W397
W83
W92
VR5
AL
W72
W73
W398
W74
W399
W400
W75
W401
W76
W402
W78
W79
W80
W395
W94
Q117
B
D109
C221
R241
R251
W406
W407
C217
Q113
Q4 6H
Q5 2C
Q6 2B
Q7 3B
Q8 3C
Q9 3B
C417
R433
R455
C421
R441
R451
EB
Q217
W90
BL
VR7
W82
R425
Q211
R461
D430
W85
W84
Q111
R231
R225
R223
W389
W390
W391
W392
W393
W394
W387
E
W388
C903
R255
R233
R229
BE
Ref. No. Address
Q103 4F
Q104 4F
Q105 4F
Q106 4G
Q107 4E
Q108 5G
Q109 5F
Q110 5G
Q111 4E
Q112 4G
Q113 6E
Q225
EB
Q221
R437
D209
W386
BE
R245
W382
W383
W384
R423
R465
R261
R466
W385
D103
D111
W69
Q207
R419
BE
R431
W380
R413
R421
D203
C411
BE
W379
C461
W68
W381
R221
R243
R213
C211
D101
Q107
B
BE
R219
E
W70
W71
Q119
B
E
R235
BBE
Q123
4
JIHGF
C
1
KAC-6402
1
C39
C40
C305
R107
R109
IC1
R157
W17
D37
R306
C114
R305
C35C36
B
W329
58
41
C106
IC5
R354
C350
R154
C150
C4
R5
D36
C105
R105
R106
W331
W330
IC9
Q3
C314
C300
58
41
D34
C359
W326
W328
58
41
W325
C116
R300
W16
R379
R380
W323
C159
W15
C2
W327
R353
R352
W324
R181
R179
R180
C303
R303
R304
D35
C100
R381
C160
R351
C360
W14
R153
R152
C304
R100
R382
R151
R182
R302
R356
W11
R103
R104
W12
W13
W5
W6
C301
C302
R355
W9
R156
W10
W322
W7
R301
C102
W8
W321
R101
R102
W4
R155
C103
C101
C104
W320
VR1
VR4
VR3
C129
R324
R326
R325
R323
R145
W318
R123
R125
VR2
W319
W316
W2
W3
W315
W317
R126
R124
R121
W314
W313
W309
W310
R322
R321
5
71
J1
3
W312
W159
S5
W311
W308
R122
1
2
2
J2
9
10
6
D33
4
C324
C128
D32
Ach Bch
3
2
S1
W30
W301
W304
S2
W302
AB-A
S1.INPUT
VR2.Bch SENS
S2.Bch
ST-MONO
4
W1
S3
W305
W303
W306
S4
VR1.Ach SENS
S3.Ach
ST-MONO
VR4.Bch
S5.Bch
HPF-OFF-LPF
VR3.Ach
S4.Ach
HPF-OFF-LPF
FREQUENCY
5
FREQUENCY
C315
C33
R320
C111
C351
IC7
R169
D3
W344
R329
C309
R317
R318
C310
R119
C32
W346
W345
W347
R165
C151
IC11
IC4
C112
58
41
C353
W27
C113
C153
R6
C31
R120
R367
58
41
C5
58
41
C308
R328
C109
R117
C110
R363
W342
W340
R167
W25
R313
C307
R327
R311
R312
R314
R129
R118
W335
W336
W338
W339
W26
W343
EEB
R315
R316
IC2
W341
R163
W333
W334
C313
W24
C317
C318
58
41
C108
R361
W22
W337
W20
C3
R113
C107
R127
R111
R112
R114
R360
R161
W23
R310
R308
IC6
R362
W21
C316
R307
R309
85
IC3
14
C117
R115
C118
R116
W19
R359
58
41
R358
W332
R159
58
IC10
415841
R160
R162
D610
W18
D2
C306
R110
R108
R357
R158
C115
W349
W38
R364
W32
R168
W30
D108
R250
W37
W35
R164
C312
W36
R377
R373
W31
R240
C220
R375
R371
R177
R173
W33
R128
W34
R175
R171
Q116
R254
R319
C34
R330
W29
C357
C355
C311
W28
R369
C157
C155
EB
R130
W348
R365
Q214
R265
D229
BE
Q208
C616
Q108
D110
R444
R660
W54
B
C412
C212
Q118
R252
R446
EB
W364
R659
R242
C222
B
R222
BE
R430
C908
Q218
W42
W43
W44
W51
W362
R432
D204
R422
W363
D104
VR6
AR
E
R256
Q114
R434
W361
W49
Q112
W53
R234C218
R442
C422
R424
W50
C418
EB
E
R224
W52
BE
R426
Q212
R226
W360
BE
VR8
W45
W46
R232
R456
D210
BR
C904
R230
R452
D211
W48
W358
W47
R246
R438
W359
R378R374
BE
R376
R372
R178
R174
W357
R244
C358
W356
R176
R172
Q226
C356
W41
Q124
Q222
W355
C158
C156
Q120
C41
R448
W350
W351
W352
W354
C42
R370
C38
R366
C352
IC8
C354
W353
C37
R170
R166
C152
IC12
BE
W40
58
41
C154
W39
R368
58
41
R236
R447
W376
R201
C201
R217
R249
W66
C413
R417
Q205
W59
R215
C213
Q115
C219
R239
R203
BE
W65
R415
BE
C209
C215
R227
R253
R427
C415
C409
C407
C459
C403
R403
Q201
R401
Q101
C203
R205
C259
E
R405
BE
BE
C420
R440
BE
BE
C207
W64
R454
Q216
W62
W61
W374
Q103
W375
R450
BE
Q204
Q203
W373
Q102
C204
R206
Q104
W372
D208
C408
R406
C404
R404
Q202
C210
C216
R228
W63
Q224
R436
EB
Q220
D205
W55
R428
C416
C410
BE
BE
BE
C460
BE
R202
R204
C260
C208
R408
R216
R416
BE
BE
W369
R208
R218
C214
R418
C202
Q106
R212
C414
Q206
W368
C902
R412
C406
C402
C206
R210
W367
C906
W366
R410
W365
BE
W58
R402
R214
Q210
B
R414
Q110
E
D22
R266
D102
R220
W57
R420
W56
D106
Q122
W371
W370
BE
R238
BEEBE
R248
Q126
Q225
BEBEB
EB
Q221
W378
W69
Q209
Q207
R431
W380
R421
B
W381
211
5
BE
Q119
E
BE
C411
W68
D101
Q107
R219
W70
W71
B
R419
D201
R413
C405
W379
C461
C205
R213
B
E
D105
R235
C261
Q105
R209
Q109
EB
R409
R211
W67
D107
C905
R411
R407
C401
W60
R207
W377
C901
B
Q123
Q4
6
Ref. No. Address
Q114 6G
Q115 5F
Q116 5H
Q117 5E
Q118 5G
Q119 5E
Q120 5H
Q121 5D
Q122 5G
Ref. No. Address
Q123 5F
Q124 5H
Q125 5D
Q126 5G
Q201 4F
Q202 4F
Q203 3F
Q204 3F
Q205 3F
Ref. No. Address
Q206 3G
Q207 3E
Q208 3G
Q209 3F
Q210 3G
Q211 3E
Q212 3G
Q213 2E
Q214 2G
Ref. No. Address
Q215 3E
Q216 2F
Q217 3E
Q218 2G
Q219 2D
Q220 2G
Q221 2F
Q222 2H
Q223 2D
Ref. No. Address
Q224 2G
Q225 2E
Q226 2H
Q601 5B
Q602 5B
Q603 5B
Q604 6B
Q605 6B
Q606 6B
Ref. No. Address
Q610 6C
Q611 6C
Q612 6C
Q613 6C
Q614 6C
Q615 6D
Q616 6C
Q617 6D
Q618 6C
7
5
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