Kenwood KAC-7203 Service manual
POWER AMPLIFIER
KAC-7203
SERVICE MANUAL
© 2006-11 PRINTED IN JAPAN
B53-0467-00 (N) 957
Stereo/Bridgeable
BOOST
CONTROL SYSTEM
Accessories
(W01-1606-05) x2
Power Amplifier
Fuse (40A)
(F52-0016-05)
Screw set
(N99-1794-05)
Dressing Panel
(A21-6559-02) : (K type)
(A21-6560-02) : (E,M type)
E,M type
K type
Connecting cord assy
(E30-6145-05)
19cm
This product uses Lead Free solder.
This product complies with the
RoHS
directive for the European market.
KA C-7 203
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)
HPF
50-200Hz
IC3(X08)
LPF
50-200Hz
HPF
50-200Hz
COMPONENTS DESCRIPTION
● PREAMPLIFIER UNIT (X08-4190-12)
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 (X09-5830-12)
Ref. No. Application / Function
IC1,12,16 Input isolation amplifier
IC5 DC/DC converter
IC6 Temperature detection comparator
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
Q201~204 Power amplifier initial step differential driving
Q205~208
Power amplifier second step differential driving
LPF/OFF/HPF
15V
IC4-7
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
Q209,210 Current limiter
Q211,213 Temperature detection for idling
Q215~218 Current limiter
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-7203
PC BOARD (FOIL SIDE VIEW)
PREAMPLIFIER UNIT X08-4190-12 A/2 (J76-0069-22)
R148
W265
W252
C118
C604
CN3
W264
R142
W263
R146
W251
2
1
31
WH1
TP7
W266
58
C116
W202
W201
58
IC7
CN1
D614
C602
R603
13
W267
IC6
W258
R144
W256
W255
R145
W253
41
C117
R147
C58
C57
C153
TP154
TP159
TP160
R604
R141
R137
41
C115
W262
W261
W257
0dB
R143
1
W26
TP153
R152
R157
C152
R156
TP155
R154
C155
C156
R160
C603
W270
C60
W210
R135
W269
C109
14
IC5
C59
W268
18dB
W260
W254
W259
43652
W25
R153
W19
C154
W14
R155
R158
R162
TP161
R159
TP158
R161
R601
W212
85
W207
W58
W10
W8
W6
W5
W4
W271
W211
R140
C110
R134
R138
W273
W205
W206
146352
BASS BOOST
VR102
W57
W24
TP157
W62
TP127
R121
W152
C124
W272
W209
R136
R132
58
R130
200Hz
50Hz
VR152
W60
W61
W56
W55
TP156
58
IC3
W11
R126
58
TP107
IC4
W59
C158
C53
W208
W204
W277
14
TP162
IC2
W275
W274
41
W203
W276
C157
R163
C51
14
W2
W1
R131
R129
LOW PASS
W7
R139
R133
W30
TP163
R122 R128
TP126
W151
C123
W16
TP106
C103
TP113
W39
50Hz
VR101
HI PASS
W15
TP152
C105
R105
W35
R109
R107
R111
200Hz
W22
TP119
C107
TP117
W52
5
1
W21
TP115
85
C113
TP121
S6
W36
TP114
6
10
IC1
W20
W53W54
C112
W51
C108
OFFLPF
W38
HPF
INPUT SENS
W18
W13
R104
TP116
R108
41
C106
TP118
1
S1
ST
R124
1
4
R123
MONO
3
6
5V
VR4
325614 3 2
W17
W9
TP105
C104
R106
R110
W3
200 V
5614
W12
W40
W37
W34
W33
W32
W31
W23
C52
C54
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
113
TP5
CN8
ISO-GND-2
14
TP13
FAN+B
W27
TP3
VR1-R
ISO-GND-1
TP9
D-GND
TP11
+15V
2
3
4
X08 B/2
TP61
TP60
TP62
3
13
42
TP64
TP65
1
J1
VR61
BOOST
LEVEL
R623
VR62
3
FREQUENCY
1
R624
TP63
PREAMPLIFIER UNIT X08-4360-10 (J76-0379-02)
X08-4190-12
Ref. No. Address
IC1 4C
IC2 4B
IC3 3B
IC4 2B
D1
C1
R1
CN1
31
Ref. No. Address
IC5 2B
IC6 2A
IC7 3A
Refer to the schematic diagram
for the values of resistors and
capacitors.
5
6
7
3
F G H I J
W26
1
9
0
Q
E
C
L
KAC-7203
1
2
3
4
5
6
PC BOARD (FOIL SIDE VIEW)
AUDIO UNIT X09-5830-12 A/2 (J76-0073-21)
C5
C3
TH202
Q226
R258
BEBEBE
R232
C222
R250
W614
R342
W138
Q222
W146
EB
W143
Q220
BE
W149
R110
W386
58
IC16
14
R109
W150
R103
C101
R101
R102
W144
1
4
R105
R260
R240
W145
W387
W388
C109
W147
W17
W139
R106
C103
R220
W140
W141
R108
R107
W142
D261
C108
C104
W136
R243
W385
R216
R222
W137
R168
R624
W362
Q213
W312
Q224
BE
TH602
C112
R115
R113
R117
C114
C113
R116
R112
R114
W151
C111
R104
C102
W148
37
Q218
EB
R248
Q2
R639
R638
W135
R290
W124
W125
C216
W384
W133
Q216
BE
R238
C220
R230
EB
W356
Q210
R218
EB
C212
Q206
W129
W131
W383
C144
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
R246
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
W156
W161
D204
Q607
W3
C117
W159
BE
C118
R111
W157
W155
W154
W152
W352
W113
W392
C116
R119
IC12
14
R118
C115
W389
C110
W342
W348
W353
W393
W315
Q619
58
C105
D4
W123
W120
R2
C612
W119
C218
C214
Q208
R159
58
R160
C139
R129
C120
IC1
14
C123
R184
W114
C138
R158
R128
R124
W376
R4
C136
C119
R157
C135
58
R186
R122
W374
W116
R280
R287
W375
W115
C167
C150
W373
J2
C611
R214
R228
Q282
R206
R208
C155
D106
10
W371
W112
W110
C210
C208
C264
BE
Q242
BE
W390
D229
W105
W111
R151
IC9
17
R152
W372
W109
D107
D105
9
R264
C170
R181
R125
C151
W370
W107
R636
C202
W108
814
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
D3
Q202
BEBE
C206
C228
BE
Q241
BE
R282
W97
W364
IC13
58
W92
C134
W98
C166
R147
R185
C153
J4
W96
W357
C4
W359
D255
W78
W79
D254
W87
W88
W89
W90
Q201
R241
R209
BE
BE
C205
C227
C201
R203
C203
W94
W95
W93
W91
W361
R149
C133
14
W343
W363
W153
R153
R154
C132
C131
C147
R145
C146
R146
C148
W358
R171
R179
R169
W84
13
24
D205
W86
C161
Q203
R150
R148
R156
R177
Q257
W82
Q225
W85
W81
R263
R211
W83
W351
C130
D108
R633
EB
EB
Q255
R247
C209
R213
W80
C263
W347
W345
C129
W346
C608
EB
B
BE
Q101
R176
EB
R634
C609
W349
B
Q610
R617
C606
W344
C207
R249
R289
C226
W77
Q612
Q611
Q613
R629
R343
R261
C221
Q217
EB
R231
W75
D253
C225
W70
W71
W72
W76
W338
W339
R138
C127
R132
814
IC8
17
R133
R141
C128
W335
R139
R632
E
W336
D613
Q621
R630
R635
E
W340
D608
W74
C125
W334
R143
Q614
BE
TH201
W73
C607
W333
W337
EB
EB
Q251
W65
W68
W66
W69
W67
W332
R142
R140
R134
R136
814
IC7
17
R137
R135
C126
R631
D614
C610
C604
BE
BE
R622
R619
EB
R626
C605
W62
W64
Q253
C156
W331
Q622
W60
Q609
W63
W330
R660
W61
W325
R664
W611
W327
W328
W329
W324
W326
W323
R620
R668
D601
Q229
W59
R621
W322
Q617
D615
R627
C601
W58
Q615
R663
BE
D602
W57
C223
R606
Q602
W56
R666
R603
B
C7
W54
W320
R658
D603
BE
W55
W53
Q616
BEBE
R665
W321
R604
Q601
C602
D
R235
W40
W41
D605
R613
W38
Q604
D612
R271
W24
W25
R225
BE
BE
Q211
C261
W36
R602
BE
Q606
R616
R233
W391
D610
Q623
D607
D203
E
R229
C21
W102
EB
R239
R251
W3
C215
C217
C21
W31
R205
B
Q2
R207
R6
W29
W28
W31
W27
W32
W35
W30
W33
R614
R29
C20
W
W47
R173
R625
EBBEBEBE
W610
Lch
VR1
R257
W52
W50
W46
W39
R202
W44
W45
W49
W6
W42
W43
W48
W51
R667
C618
R662
R661
R406
BE
Q618
R659
BE
C616
R611
R615
R610
R612
W319
Q605
R609
D606
R607
Q603
R608
BE
R605
E
C603
D604
LINE
OUT
LINE
IN
SPEAKER
LEVEL
INPUT
REMOTE
SP
7
Refer to the schematic diagram for the values of resistors and capacitors.
4
W
R614
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
C213
W317
Q207
Q215
W318
EB
W28
W26
W27
W18
EBEB
R237
Q620
TH605
R245
Q209
BE
R223
D251
R5
W22
R649
R650
W23
P1
W21
W20
Q608
Q223
R217
SPEAKER OUTPUT POWER IN
R341
BE
BE EB
R155
D260
R215
C211
R221
R219
E
Q205
B
D611
R642
85
C614
IC6
R646
C19
W106
41
C617
R643
R648
R618
R657
W354
R651
R647
C6
C9
R8
C615
D617
W355
R656
W314
W162
W2
R28
D616
R652
R653
W37
W5
W313
R623
W117
J3
ONMLK
KAC-7203
1
X09-5830-12
Ref. No. Address
X09 B/2
D609
WH1
13
C613
W16
W15
TH601
W14
W13
W12
D5
W609
R30
C18
L3
W10
L1
Q227
C8
R7
C11
W607
W606
L2
C1
W11
D6
W608
Q4
SGDSGDSGDSGDSGDSGD
Q6
Q8
C10
W4
W7
W8
W9
W602
D2
D1
W603
W601
R10
Q3
Q5
R9
Q7
Q10
R15
R11
W311
W309
BE
R13
Q9
W306
R16
W307
W310
W1
W308
D9
C14
R22
R21
R23
D7
BE
BE
R14
BE
W305
W303
Q11
R12
BE
Q12
16 9
D8
R27
R19
W304
C13
BE
Q14
D10
Q13
R25
W302
C16
W301
81
R24
C17
C15
IC5
R26
R20
R17
R18
IC1 6H
IC5 6N
IC6 5K
IC12 6G
IC16 6G
Q1 2H
Q2 2H
Q3 4N
Q4 3N
Q5 4N
Q6 3N
Q7 5N
Q8 4N
Q9 5N
Q10 5N
Q11 5N
Q12 5N
Q13 5N
Q14 5N
Q201 3H
Q202 3H
Q203 3I
Q204 3H
Q205 3K
Q206 4G
Q207 3K
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
Q613 6I
Q614 6I
Q615 5J
Q616 5J
Q617 6J
Q618 6J
Q619 5G
Q620 2K
Q621 6I
Q622 6I
Q623 6J
2
3
4
5
6
7
5
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