Kenwood KAC-7204 Service manual
POWER AMPLIFIER
KAC-7204
SERVICE MANUAL
© 2008-1 PRINTED IN JA PAN
B53-0612-00 (N) 519
Dressing Panel
(A21-6640-01): (E,K type)
(A21-6641-01): (M type)
Fuse (40A)
(F52-0016-05)
FUSE[40A]
Accessories
(W01-1606-05)
Stereo/Bridgeable
Power Amplifier
Stereo/Bridgeable
POWER IN
Power Amplifier
P.CON
LEFT RIGHT
[MIN] [MAX]
BASS BOOST
INPUT
LEVEL[dB]
BRIDGED
SPEAKER OUTPUT
SENSITIVITY[V]
Screw & wrench key set
(N99-1820-05)
E,K type
M type
OFFLPF
HPF
FILTER
LPF
FREQUENCY[Hz]
HPF
FREQUENCY[Hz]
LINE IN LINE OUT
SP LEVEL INPUT
SIGNAL SENSING
TURN-ON
Connecting cord assy
(E30-6145-05)
19cm
This product complies with the
This product uses Lead Free solder.
RoHS directive for the European market.
KAC-7204
BLOCK DIAGRAM
L
LINE IN
(0.2~5V)
R
L
LINE OUT
R
L+
LRR+
-0.83dB_ATT
+6.85dB_AMP
=6.0dB
IC2
ISO-AMP
IC1
ISO-AMP
-0.83dB_ATT
+6.85dB_AMP
=6.0dB
LPF/OFF/HPF
IC7
H.P.F
FREQ
IC7
L.P.F
H.P.F
(50~200Hz)
FREQ
(50~200Hz)
FREQ
(50~200Hz)
Q611,612
DC-OFFSET
DET
D5,6
±
B
P-CON
PRIORITY
Q281,283
THERMAL
IC5
IC12
Q215-218,610
OVERLOAD
DET
Q1,2
±
15V
AVR
Q50,D50,52 Q605 Q604
SIGNAL
DETECTOR
SENS.
VOL
Q282,284
TH601,602,605
DET
DC/DC
CON
POWER
ON/OFF
-0.5dB_ATT
+16.4dB_AMP
=15.9dB
IC8
+15.8dB
IC8
Q241
MUTEATT
Q242
MUTEATT
Q609, 699
LC FILTER
40Hz=18dB
IC10
Bass
Boost
IC11
Bass
Boost
40Hz=18dB
POWER AMP
POWER AMP
FAN
FAN
AVR
FREQ
(40Hz)
Q201...229
Q202...226
L
R
(INV)
P-CON
BATT.
GND
SP
OUTPUT
40A x1
COMPONENTS DESCRIPTION
AUDIO UNIT (X09-8760-10)
●
Ref. No. Application / Function Operation / Condition / Compatibility
IC1,2 Isolation circuit
IC5 DC/DC converter
IC6 Temperature ATT control ATT2=on by pin1=H, ATT1=on by pin7=H
IC7 HPF
IC8 Buffer amplifi er, Rch inversion amplifi er
IC10,11 bass-boost
IC12 LPF
Q1,16 +15V power supply
Q2,17 -15V power supply
Q3~8 DC/DC switching FET
Q9~14 DC/DC switching FET drive Tr
Q15 Temperature ATT reference power supply
Q50,51 auto_pcon_off Disables operation of the auto_pcon circuit when the pcon_ is connected
2
KAC-7204
COMPONENTS DESCRIPTION
Ref. No. Application / Function Operation / Condition / Compatibility
Q201~204 Differential fi rst stage amplifi er
Q205~208 Differential second stage amplifi er
Q209,210 Differential second stage current mirror
Q211,213 Temperature compensation Tr
Q215~218 Current limiter
Q220,222~227,229 Power amplifi er fi nal Tr
Q241,242 mute_Tr Mute_on when is ON
Q251~258 Power amplifi er driver
Q281,282 ATT2_Tr The signal level becomes -3dB when is ON
Q283,284 ATT1_Tr The signal level becomes -1.5dB when is ON
Q602 Mute control ON when is pcon_off
Q603,698 Power supply for the mute_Tr
Q604 SW14V Power supply for DC/DC_IC
Q605 Pcon control ON by pcon=H
Q606 Over voltage detection Turn off Q605 when over voltage is detected
Q609 Power supply for FAN
Q610 Over current protection
Q611,612 DC protection
Q613,614 Latch circuit for DC protection Hold the protection operation while the DC protection is being operational
Q615,616 Shock noise prevention circuit
Q617,618 Shock noise prevention circuit control
ADJUSTMENT
NO. ITEM ALIGNMENT POINT METHOD ALIGN FOR NOTE
Connect a DC voltmeter between check land.
Lch: Q223_emitter
Rch: Q224_emitter
Lch
+
Q224
Q220
Rch
VR6
R243
W21
VR5
↔
↔
W148
X09-876
W148
W21
Q223
R245
Q227
2.5mV after 5minutes from power on
Lch 2.5mV
+
DC voltmeter
-
1
IDLE
CURRENT
VR5 (Lch)
VR6 (Rch)
Rch 2.5mV
-
DC voltmeter
3
A B C D E
C129
C121
6
4
W
W117
1
W120
E
KAC-7204
1
PC BOARD (FOIL SIDE VIEW)
AUDIO UNIT X09-8760-10 (J76-0476-11)
E
B
D6
W194
W409
W412
W5
W193
W313
W406
W416
W427
W191
W312
W428
Q10
Q11
W401
W402
W403
W404
R34
W308
C14
R22
D9
C16
W309
W310
R49
R9
R15
R13
BE
BE
BE
Q12
R10
W311
C17
Q9
BE
Q13
BE
R24
IC5
D10
BE
R16
R14
BE
Q14
R18
Q15
C10
R30
W332
C18
L2
W426
W425
W331
C11
R35
W164
W302
W190
W304
W307
R21
R23
C15
R26
R25
18
R19
W303
W305
169
R53
D8
R27
R17
R650
C24
R20
W306
C13
L3
TH605
W4
C1
2
D5
W195
R57
W405
3
4
5
SDG
Q8
R55
W408
W407
SDGSDGSDGSDGSDG
Q6
R12
W411
W410
Q4
R56
W415
W413
W414
Q7
R54
W418
W419
W417
Q5
R11
W421
W420
W422
Q3
W424
W423
D2
D1
6
W189
W188
W187
W186
L1
EB
W185
W182
Q227
W183
W184
C7
R6
D611
C603
W166
R616
R614
BATT
Q602
D605
C621
W301
R273
R606
D602
BE
Q606
J3
P1
W181
W192
D604
BE
R613
W176
W177
D699
C602
R692
D606
D607
-B
W180
R8
C8
R7
W297
BE
W165
W300
Q605
W179
W295
C601
R615
C9
Q603
R605
R604
R603
R155
W178
R5
W16
BE
W298
W175
D7
R611
W296
R694
BE
R695
R607
W11
W12
W171
W172
W170
W15
C699
R28
W168
W169
Q604
EB
R693
C19
+B
W167
R627
R608
C6
R612
D603
W294
W293
R699
R245
W163
R610
Q698
SP-GND
W173
R609
W174
CN2
21
R59
R61
-B
W429
TH-GND
D600
W162
W158
W159
W160
W161
R620
SP-L
W157
W292
+B
R58
W153
R621
W155
BE
C617
EB
Q223
SP-L
W430
W150
W156
-15V
W152
Q50
Q51
R60
W154
R29
C20
Q211
W151
BE
W144
4.5V
SP-R
W145
1234567
W140
SW14V
W27
C52
W291
R62
W118
W119
W146
W147
W138
W139
W148
W149
SP-R
W137
R289
W143
R691
D50
W135
R640
D601
C51
R275
R290
C600
W128
W129
C50
W132
W133
W134
W125
-15V
W124
W431
W131
W288
W93
D609
W13
W141
W123
+15V
W122
Q609
EB
W1
W1
W
R147
R72
R626
X09-8760-10
Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address
IC1 5H IC8 5G Q2 2F Q7 4B Q12 3C Q17 2F Q203 4H Q208 4H Q215 2H
7
IC2 5H IC10 6F Q3 5B Q8 3B Q13 3C Q50 5E Q204 4H Q209 3H Q216 5I
IC5 3C IC11 6F Q4 4B Q9 3C Q14 3C Q51 5E Q205 4G Q210 3H Q217 3H
IC6 4F IC12 6H Q5 4B Q10 3B Q15 3C Q201 4H Q206 3H Q211 2D Q218 2H
IC7 5G Q1 2F Q6 4B Q11 3B Q16 2F Q202 4H Q207 4G Q213 3I Q220 5I
4
C51
W135
EB EB
R275
BE
D609
C600
8
9
8
9
R72
W93
-15V
+15V
W128
W124
W122
W129
Q609
EB
R640
R626
W14
W132
W133
W134
W136
R290
601
W431
W141
W142
W130
3
W121
W131
W288
C50
W123
W125
R147
Q2
Q17
W117
W120
W116
Q699
BE
D608
W284
D616
W127
W97
W286
W104
W276
VR4
W287
C127
C129
C121
R149
W108
W109
W110
W111
R74
W113
W114
W115
C3
LED+B
W107
R697
W278
D610
W280
W281
C123
W283
R159
IC10
58
W106
FAN+B
R619
W279
R165
C125
W323
W105
C605
W277
D612
JIHGF
KAC-7204
1
W217
Q257
R261
BE
C205
C223
58
R160
L-NF
W61
W232
B
W196
C107
R115
R162
W62
W229
E
Q225
Q255
BE
R219
Q209
W59
D251
R213
C209
C263
R263
C207
Q203
BE
R203
C203
R227
W54
R132
W328
W199
W55
R161
C141
C139
W60
C146
W231
W228
W299
R279
D205
W221
R235
D260
C226
W230
D152
R211
C227
W50
R209
E
Q201
C201
W58
R118
C108
R116
W226
W53
W56
W227
R158
C137
R156
14
IC12
58
C145
W45
W46
W47
W48
W51
W52
R242
W327
R168
R108
B
W49
D254
Q204
C116
VR1
R157
R249
C231
R231
D255
-B
R214
C210
W225
R224
W39
C264
W224
C206
B
Q202
C202
W223
C150
W285
C132
R126
IC2
14
C106
R106
BE
R229
C219
C230
R237
BE
C221
R236
W219
W44
W43
W41
W40
R264
R212
BE
R210
R204
C204
R228
W218
R152
R112
C114
R170
58
R114
R104
R154
C135
C140
C698
HPF
W245
W320
Q215
W215
Q217
W216
Q210
C208
W213
E
R110
R100
SP-R
BE
BE
D261
R218
R216
R208
Q208
W212
W214
C228
R124
C134
W42
C34
-B
+B
D206
Q254
Q252
BE
R220
R222
C212
BE
BE
C214
W210
C218
R272
R234
BE
B
Q256
R262
R153
R171
C131
C36
W38
PIN-G
W37
R105
W211
C124
Q218
R232
C222
W315
SP-R
W36
Q206
R206
W206
W207
W209
Q258
E
C115
R111
R125
IC1
14
R107
R103
LRR
D104
D103
BE
W266
R260
C216
C113
C105
W208
58
J1
C232
W35
W34
R278
C149
R113
R250
+B
W31
W33
W29
W32
W30
R282
W28
R123
C133
W203
W205
W204
RL
R101
W202
R276
R274
W25
R109
W26
W24
C101
R248
R243
R246
D102
R102
R258
W23
R169
L
W22
C102
W20
MAX
W21
C103
VR6
R230
C233
R238
W201
C104
R226
TH602
D204
E
Q222
B
Q226
E
B
R
R240
E
Q224
B
C220
EB
E
Q220
B
D101
C111
J2
1092
W322
C112
R129
R121
Q216
Q213
R128
1
2
3
B
E
4
5
C109
C110
R50
W326
R127
R122
W200
D52
R120
6
Q1
B
Q16
D4
W275
R1
R2
R71
C5
W274
R625
C618
C604
R622
W271
R658
C616
D615
W99
R696
C57
R51
R52
C58
W101
W238
C148
W100
C147
C136
W272
14
R167
E
R73
R3
R4
SP-R
SP-L
C2
C613
R628
Q614
C607
R661
R659
R602
W198
W77
W269
W270
BB
R150
R146
W220
58
W112
W96
D617
R698
C609
R635
R631
BEBEBE
R653
R656
W268
R646
W95
W317
W318
IC11
C4
EB
D3
TH601
MAX
W267
W94
W92
CN1
D624
C620
21
C619
W263
BE
C610
D614
R632
W265
Q611
R664
R660
Q617
Q618
R643
R651
R652
R648
58
W314
IC6
41
R647
R618
R649
R624
C614
W262
W400
AMP-IN-R
W91
R422
R423
VR3
R148
C138
14
W90
R142
R633
W321
W259
W88
C130
W89
Q229
W258
+B
W79
Q612
W261
-15V
R137
R140
W80
W81
W82
W83
W84
W85
W86
W87
R638
R600
W75
C608
W78
L
R225
W76
R251
W255
W73
W13
Q613
R634
BE
BE
R630
W254
Q616
BE
R662
R665
R663
W256
R639
C612
Q242
C615
R636
C611
W257
W197
W74
AMP-IN-L
C128
R144
R138
IC8
R143
R151
R145
R135
SENS
W252
W72
R163
W253
W260
R239
C215
C225
D613
58
41
R141
Q241
BE
R136
R139
VR5
R233
L+
W70
W247
Q610
B
R667
BE
BE
R283
W273
R266
D229
S6
H/OFF/L
E
W248
W249
Q284
W250
R257
R271
W325
R617
Q615
BE BE
R914
BE
R265
R915
W330
W246
W243
W244
D295
C119
W71
D253
R629
R668
Q283
R916
W10
Q253
R666
Q282
W65
W66
W67
BE
L-
W68
W242
C606
W240
R207
W239
R223
Q281
R281
BE
R285
R286
D296
+15V
R201
R280
C122
R134
R133
W241
R247
R277
EB
Q251
C217
C213
BE
BE
C211
R221
R202
R287
W63
C126
C120
R117
W69
R131
VR2
W235
W64
C143
BE
R217
D203
R215
Q207
R205
Q205
W236
R241
W324
AGND
C118
R130
IC7
14
R119
C117
LPF
W234
W237
W282
W233
BB-G
SENS.
HPF-FLPF-F
OUTIN
Refer to the schematic diagram for the values of resistors and capacitors.
Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address Ref. No. Address
Q222 2I Q227 2D Q252 3H Q257 2G Q284 4G Q606 6D Q613 3G Q618 4F
Q223 2E Q229 2G Q253 3G Q258 4H Q602 5D Q609 3F Q614 4F Q698 5E
Q224 4I Q241 4G Q254 3H Q281 4G Q603 5D Q610 3G Q615 4G
Q225 2H Q242 4G Q255 2H Q282 4G Q604 5D Q611 4F Q616 4G
Q226 3I Q251 3G Q256 5H Q283 4G Q605 6D Q612 4G Q617 4F
7
5
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