KENWOOD KAC-252 Service Manual
POWER AMPLIFIER
KAC-7202/7252
SERVICE MANUAL
© 2005-3 PRINTED IN JAPAN
B53-0248-00 (N) 1708
KAC-7252
(E type,M type)
CONTROL SYSTEM
REMOTE CONTROL
KAC-7202
Stereo
Powe
Bridgeable
Amplifie
Dressing Panel
(A21-4463-02)
: KAC-7252
(A21-4525-02)
: KAC-7202
Dressing Panel
(A21-4467-02)
: KAC-7252(K type)
(A21-4468-02)
: KAC-7202
(A21-4526-02)
: KAC-7252(E type),
KAC-7252(M type)
KAC-7252
(K type)
Except KAC-7202
Remote control
9
1
1
2
1
5
6
5
7
5
1
7
5
0
L
E
8
5
V
1
E
8
L
[
d
B
]
4
0
F
R
E
Q
U
E
N
C
Y
1
[
H
0
0
z
]
Accessories
(W01-1606-05)
9
5
Fuse (40A)
(F52-0016-05)
Modular cable
(E30-6240-15)
6m
Screw set
(N99-1759-05)
Except KAC-7202
Mouting hardware
(J22-0301-14)
Connecting cord assy
(E30-6145-05)
19cm
KAC-7202
Screw set
(N99-1766-05)
This product uses Lead Free solder.
KA C-7202/7252
BLOCK DIAGRAM
ISO AMP
LINE IN
LINE OUT
LINE OUT
LINE IN
SP IN
SP IN
L
L
R
R
L
R
IC12,16
MO/ST
SENS
IC1
IC1(X08)
IC3(X08)
COMPONENTS DESCRIPTION
● PREAMPLIFIER UNIT (X08-4190-1x)
Ref. No. Application / Function
IC1 HPF
IC2 Phase reversal amplifier (Lch only)
IC3 LPF
IC4~6 Bass-boost circuit
IC7 Bass-boost mixing amplifier
● AUDIO UNIT (X09-5830-1x)
Ref. No. Application / Function
IC1,12,16 Input isolation amplifier
IC5 DC/DC converter
IC6 Temperature detection comparator
IC7,8 For adjusting bass-boost f
IC9 For adjusting bass-boost gain
IC13 Bass-boost phase shifter
IC15 Bass-boost mixing amplifier
Q1,2 ±15V AVR
Q3~8 DC/DC converter FET
Q9~12 DC/DC converter FET driver
Q13,14 For controlling DC/DC converter FET driver
LPF/OFF/HPF
HPF
50-200Hz
LPF
50-200Hz
HPF
50-200Hz
REMOTE
CONTROL
f, GAIN
f=40-100Hz
GAIN=0-18dB
15V
IC7-9,13,15
BASS
BOOST
40-100Hz
BASS
BOOST
40-100Hz
AVR
Q241,242
MUTE
MUTE
CONTROL
D.D. CON.
POWER AMP
Q201-258
SP OUT L
SP OUT R
P-CON
BATT
GND
Ref. No. Application / Function
Q101 Remote controller reference voltage
Q201~204 Power amplifier initial step differential driving
Q209,210 Current limiter
Q205~208
Power amplifier second step differential driving
Q211,213 Temperature detection for idling
Q220,222~227,229
Power amplifier final
Q241,242 Power amplifier mute
Q251~258 Power amplifier driver
Q280,282 Power amplifier ATT (-3dB)
Q601,615~618 Power-ON shock preventer circuit
Q602 P-Con OFF detection
Q603 Mute drive
Q604,605 P-Con control circuit
Q606 Excess voltage detection
Q607,608,619,620
Temperature detection control circuit
Q609 Fan power supply
Q610 Excess current detection
Q611,612 DC detection
Q613,614 DC detection for latch
Q621,622 For LED control
Q623 Temperature detection control circuit
ADJUSTMENT
No. ITEM ALIGNMENT POINT METHOD ALIGN FOR NOTE
1
IDLE VR1 (Lch)
CURRENT VR2 (Rch)
2
Connect a DC voltmeter
between check land 2.5mV
(Refer to PC BOARD)
After Power on
5 minutes
EDCBA
KAC-7 202/7252
PC BOARD (FOIL SIDE VIEW)
PREAMPLIFIER UNIT X08-4190-1x A/2 (J76-0069-12)
R148
CN3
W265
W252
C118
C604
W264
R142
W263
W251
D614
C602
TP7
C116
W202
W201
58
R146
CN1
12
13
W267
W266
58
IC6
W258
41
IC7
C58
C57
C153
TP154
R603
R604
R141
41
C115
R144
W256
W255
R143
R145
W253
C117
R147
TP153
C152
R156
R154
C155
C156
TP159
TP160
C603
W270
W210
R135
R137
C109
14
W262
C59
W261
W257
18dB
0dB
W260
W254
W259
43652
1
W26
W25
R153
R152
R157
C154
TP155
R155
R158
R162
TP161
R159
R160
TP158
R161
R601
C60
W269
IC5
W268
W207
W58
W19
W14
W4
W212
W211
85
BASS BOOST
VR102
W24
W10
W8
W6
W5
W271
W272
R136
R140
R132
C110
58
R134
R138
R130
50Hz
W273
W205
W206
VR152
146352
W60
W56
W57
58
TP157
IC3
W11
W62
TP127
R126
R121
TP107
W152
C124
W208
W209
W274
IC4
200Hz
W204
W59
W61
W277
W55
TP156
14
C158
TP162
58
IC2
C53
W1
W275
41
R129
W203
LOW PASS
W276
C157
R163
C51
14
W2
R131
R139
R133
W30
TP163
W7
R122 R128
TP126
TP106
W151
C123
W39
HI PASS
W16
C103
TP113
50Hz
VR101
W15
TP152
C105
R105
R111
W35
200Hz
R109
R107
W22
C107
W52
5
1
W21
TP119
TP115
85
TP117
TP121
S6
W36
C113
6
10
W53W54
C112
IC1
TP114
W51
OFFLPF
W38
HPF
W20
W18
TP116
41
C108
S1
1
4
3
6
200 V
5V
VR4
5614
325614 3 2
INPUT SENS
W17
W13
W9
R104
TP105
R108
C104
C106
R106
R110
W3
TP118
W12
ST
R124
R123
MONO
W23
W33
W40
W37
W34
W32
C54
C52
W31
BB-R
VR1-L
TP1
TP164
TP10
TP8
W29
RCA-G
TP2
ISO-L
TP15
ISO-R
BB-L
TP12
-15V
LOGO-LED
TP14
W28
W27
113
TP3
VR1-R
TP5
CN8
ISO-GND-1
ISO-GND-2
TP11
14
+15V
TP13
FAN+B
TP9
D-GND
1
2
3
4
X08 B/2
R623
VR62
1
3
TP63
R624
FREQUENCY
Refer to the schematic diagram for the values of resistors and capacitors.
TP60
TP61
TP62
3
13
42
TP64
1
TP65
BOOST
LEVEL
J1
VR61
X08-4190-1x
Ref. No. Address
IC1 4C
IC2 4B
IC3 4B
IC4 2B
IC5 2B
IC6 2A
IC7 3A
5
6
7
3
F G H I J
W26
1
9
0
Q
E
C
L
KAC-7202/7252
1
2
3
4
5
6
PC BOARD (FOIL SIDE VIEW)
AUDIO UNIT X09-5830-1x A/2 (J76-0073-11)
C5
C3
TH202
Q226
R258
BEBEBE
EB
R232
C222
R250
W614
R342
W138
Q222
W146
W142
EB
R260
Q213
R240
W136
Q224
BE
TH602
W149
C112
R115
R110
R113
R117
C114
IC16
14
C113
R116
R109
R112
R114
W151
C111
W150
R104
R103
R101
R102
C102
W148
37
1
4
W143
Q220
BE
W386
W144
58
C101
R105
W145
W387
W388
C109
W147
W17
W139
R106
C103
R220
W140
W141
R108
R107
D261
C108
C104
R243
W385
R216
R222
C144
W137
R168
Q218
R248
Q2
R639
R638
W135
R290
W124
W125
C216
W384
W133
Q216
BE
R246
R238
C220
R230
EB
W356
Q210
R218
EB
C212
Q206
W129
W131
W383
R165
W127
R166
W134
C145
W501
R167
R131
D101
R120
C157
W381
D102
C158
W382
R121
R130
W379
W132
W380
W19
D103
R178
W128
W130
J1
5
62
W126
W121
W122
R226
Rch
VR2
W118
W377
R224
EB
D152
W502
R161
C140
R163
IC15
14
R164
C141
R162
C124
C121
W378
C122
C165
C149
2.5mV
Rch
DC voltmeter
CN1
R174
D206
EB
Q254
EB
Q252
R236
R272
R262
R234
Q256
EB
W350
Q258
EB
R175
R344
W158
W160
13
214
1
W161
W156
D204
Q607
C118
W3
C117
W159
R111
BE
W157
W155
W154
W152
W352
W113
W392
14
R118
C115
C110
W348
W353
W393
W315
C116
R119
IC12
W389
W342
R624
W362
W312
Q619
58
C105
D4
W123
W120
R2
C612
W119
C218
C214
Q208
R159
58
R160
R129
C120
14
C123
R184
C139
IC1
W114
C138
R158
R128
R124
W376
R4
R157
C136
C119
C135
58
R186
R280
R287
R122
W374
W116
W375
W115
C167
C150
J2
C611
R214
R206
R208
D106
W373
10
W112
C208
R228
Q282
C155
W372
W109
D107
D105
9
W371
W107
W110
R636
C210
R264
C264
C202
BE
Q242
BE
W390
D229
W105
W111
W108
R151
814
IC9
17
R152
C170
R181
R125
C151
W370
W369
R212
C204
D109
R170
C169
D104
R126
R637
R123
1
2
W104
R1
W101
R204
W103
W366
Q204
R266
C143
C168
R187
W368
R3
W99
R227
W367
R265
W100
C137
C152
C2
Q1
R242
R201
R285
Q280
D295
R127
R210
R284
C142
C4
D3
W78
Q202
BEBE
C206
C228
BE
Q241
BE
R282
W96
W97
W364
W361
IC13
58
W92
C134
W98
C166
R147
R185
C153
C148
J4
W357
D205
W359
D255
W79
D254
W87
W88
W89
W90
Q201
R241
R209
BE
BE
C205
C227
C201
R203
C203
W94
W95
W93
W91
W86
R149
C133
14
W343
W363
W153
R153
R154
C132
C131
C147
R145
C146
R146
W358
R171
R179
R169
W84
13
24
Q203
R148
R156
C161
R177
R150
Q257
W82
Q225
W85
R263
R211
W83
W351
C130
D108
W81
R633
R176
W349
C209
W80
C263
BE
Q610
EB
EB
R247
W345
W346
C606
Q255
R213
W347
R634
C609
R617
R343
R261
W344
R249
Q217
EB
R231
C221
R289
W75
C226
D253
C225
W70
W71
W72
C207
W76
W338
W339
R138
C129
C127
R132
814
IC8
17
W334
W77
R133
R141
C128
W335
R139
C608
Q612
EB
R632
E
B
W336
Q611
Q101
D613
Q613
EB
Q621
R630
R635
E
B
R629
W340
D608
TH201
W74
C125
R143
Q614
BE
W337
W73
C607
W333
EB
EB
Q251
W65
W68
W66
W69
W67
W332
R142
R140
R134
R136
814
IC7
17
R137
R135
C126
R631
D614
C610
BE
BE
R622
R619
EB
R626
C605
C604
W64
W62
Q253
C156
W331
Q622
W60
Q609
W63
W330
R660
W61
W325
R664
W611
W327
W328
W329
W326
W323
W324
R620
R668
D601
Q229
W59
R621
W322
Q617
D615
R627
C601
W58
Q615
R663
BE
D602
W57
C223
R606
Q602
W56
R666
D603
R603
B
C7
W54
W320
BE
EBBEBEBE
W55
W53
Q616
BEBE
R665
W321
R658
R604
Q601
C602
BE
R662
R605
R257
R667
R607
R202
W51
R659
BE
W48
Q618
C616
Q603
E
W52
W6
W319
R661
R608
W49
R609
W47
R625
W610
W50
R610
W42
W43
W46
W45
C618
R406
R615
D604
R173
W39
W44
BE
R612
Q605
D606
C603
Lch
VR1
W41
R611
D605
R613
W40
W38
Q604
D612
R271
R225
BE
W24
W25
BE
Q211
C261
W36
R602
BE
Q606
R616
R233
W391
D610
Q623
D607
D
R235
D203
E
R229
C21
W102
EB
R239
R251
W3
C215
C217
C21
W31
R205
B
Q2
R207
R6
W29
W28
W31
W27
W32
W33
W35
W30
R614
R29
C20
W
LINE
OUT
LINE
IN
SPEAKER
LEVEL
INPUT
REMOTE
SP
7
Refer to the schematic diagram for the values of resistors and capacitors.
4
ONMLK
W
R614
KAC-7 202/7252
Lch 2.5mV
DC voltmeter
R172
R235
D203
102
EB
R239
R251
C215
C217
R205
R207
6
W29
W31
W32
W30
W33
6
R29
C20
R229
C219
W317
Q207
C213
Q215
W318
EB
W28
W26
W27
W18
EBEB
R237
Q620
TH605
R245
Q209
BE
R223
D251
R5
W22
R649
R650
W23
P1
W20
W21
W2
Q608
Q223
R217
B
C614
SPEAKER OUTPUT POWER IN
R341
BE
BE EB
R155
D260
R215
C211
R221
R219
E
Q205
C6
C9
W355
R656
W314
D616
R652
D617
R8
R653
W37
C615
R623
W117
W313
W5
J3
D611
R642
85
IC6
41
R646
C19
W106
C617
R643
R648
R618
R657
W354
R651
R647
R28
X09-5830-1x
1
Ref. No. Address
IC1 6H
X09 B/2
IC5 6N
IC6 5K
IC7 5I
IC8 5I
IC9 5H
IC12 6G
IC13 5H
IC15 5H
IC16 6G
Q1 2H
Q2 2H
Q3 4N
Q4 3N
2
WH1
13
C613
D609
Q5 4N
Q227
D5
W609
D6
W608
Q6 3N
Q7 5N
Q8 4N
Q9 5N
Q10 5N
Q11 5N
Q12 5N
Q13 5N
Q14 5N
Q101 6I
Q201 3H
C8
R7
Q4
SGDSGDSGDSGDSGDSGD
Q6
Q202 3H
Q203 3I
Q204 3H
Q205 3K
Q206 4G
Q207 3K
3
Q208 4H
Q209 3K
Q210 4G
Q211 2J
Q213 3G
Q215 2K
Q216 4G
Q217 3I
Q218 2G
Q220 4G
Q222 3G
Q223 2K
Q224 4G
Q225 2I
Q226 2G
Q227 2L
Q229 2J
Q241 4H
Q242 4H
Q251 2I
Q252 3F
Q253 2I
Q254 3F
Q255 2I
Q256 4G
Q257 2I
Q258 4G
Q280 4H
Q282 4H
Q601 6J
Q602 6J
Q603 6J
Q604 6J
Q605 6J
Q606 6J
Q607 5G
Q608 2K
Q609 6I
Q610 6I
Q611 6I
Q612 6I
4
5
6
W607
W606
TH601
L3
C11
W12
W14
W15
W13
W16
L2
C1
R30
C18
C10
W4
W7
W8
W9
W10
W11
L1
D1
W603
W602
Q8
R10
Q3
Q5
R9
Q7
Q10
R15
R11
W311
W309
BE
R13
D10
BE
Q9
W303
Q13
BE
BE
W306
R16
Q11
W601
D2
R12
R14
Q14
BE
BE
W307
W310
W1
Q12
W308
16 9
W305
D9
IC5
C14
R21
D8
R22
R23
R27
R19
R26
R20
W304
R17
R18
C13
D7
R25
W302
C16
W301
81
R24
C17
C15
Q613 6I
Q614 6I
Q615 5J
Q616 5J
Q617 6J
Q618 6J
Q619 5G
Q620 2K
Q621 6I
Q622 6I
7
Q623 6J
5
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