Kenwood KAC-6403 Service manual
POWER AMPLIFIER
KA C-6403
SERVICE MANUAL
© 2006-1 PRINTED IN JAPAN
B53-0378-00 (N) 540
Rear panel
(A84-0410-02)
Screw washer
(N09-4215-08)
SPEAKER OUT
Screw washer
(N09-6393-08)
LEFT
RIGHT
POWERAMPLIFIER
Fuse (25A)
(F52-0014-05)
BATT. P.CON
GND
FUSE
25A
POWER IN BRIDGED
EXPLODED VIEW is on page 5.
Heat sink
(F01-3511-01)
Connecting cord assy
(E30-6144-05)
A ch FILTER B ch FILTER
OFF LPFOFF HPF
1
2
0.5
3
0.3
4
MIN
MAX
0.2
5
Ach Bch
INPUT SENSITIVITY
INPUT SELECTOR
1
2
3
4
MINVMAX
5
0.2
LINE IN
0.5
0.3
Panel
(A64-3834-02)
Screw set
(N99-1587-05)
Accessory
(W01-1606-05)
This product uses Lead Free solder.
KA C-6403
BLOCK DIAGRAM
LINE IN A
LINE IN B
SPEAKER
INPUT
AUDIO UNIT (X09-8542-70)
J1
L
R
L
R
J2
IC2
ISOLATION
AMPLIFIER
IC2
ISOLATION
AMPLIFIER
IC4
ISOLATION
AMPLIFIER
IC4
ISOLATION
AMPLIFIER
+6dB 0dB +29.5dB
S1
A-AB
Q101,102,
VR1
Ach
INPUT
GAIN
CONT.
VR2
S1
Bch
INPUT
GAIN
CONT.
C151,153,R165,167
IC9
HPF
80Hz 12dB/OCT
+1
C152,154,R166,168
IC9
HPF
80Hz 12dB/OCT
-1
S3
IC5
LPF+10dB
80Hz 12dB/OCT
S3 S3
Q3,4
AVR
15V
L2
DC/DC
CONVERTER
TH1
THERMAL
PROTECTION
IC7
+1
-3dB ATT
IC7
+1
-3dB ATT
S3
+1
-3dB ATT
-1
-3dB ATT
S2
S2
IC6
IC5
201,202
MUTE
Q605
P.CON
CIRCUIT
IC13
OVER VOLT A GE
PROTECTION
Q103-114,
119-126
POWER
AMPLIFIER
Q103-114,
119-126
POWER
AMPLIFIER
Q203-214,
219-226
POWER
AMPLIFIER
Q203-214,
219-226
POWER
AMPLIFIER
Q115-118,215-218
DC DETECT &
OVER ROAD PROTECTION
J9
L
SPEAKER
OUT A
R
L
SPEAKER
OUT B
R
P.CON
BATTERY
COMPONENTS DESCRIPTION
● AUDIO UNIT (X09-8542-70)
Ref. No Application / Function Operation / Condition / Compatibility
IC1 Buffer AMP Amplifies 6dB by decreasing impedance.
IC2 Isolation AMP Decreases common mode noise.
IC3 Buffer AMP Amplifies 6dB by decreasing impedance.
IC4 Isolation AMP Decreases common mode noise.
IC5 LPF B-Rch side is phase inverter.
IC6 -3dB ATT B-Lch side is buffer amplifier.
IC7 Buffer AMP Decreases impedance.
IC9 Phase inverter A-Lch side is buffer amplifier.
IC13 DC/DC converter Oscillates and controls DC/DC converter.
Q3,4 Constant voltage power supply Controls ±15V constant voltage.
Q5,6 DC/DC converter Switching FET.
Q7~10 DC/DC converter Drives Q5’s and Q6’s gates.
2
KA C-6403
COMPONENTS DESCRIPTION
Ref. No Application / Function Operation / Condition / Compatibility
Q11,12 DC/DC converter Turns on or off IC13 output.
Q101,102 Input mute Absorbs shook noise when power turns on or off.
Q103~106 Power AMP 1st deferential amplifier.
Q107~110 Power AMP 2nd deferential amplifier.
Q111,112 Power AMP Current mirror load for 2nd deferential amplifier.
Q113,114 Power AMP Compensates bias temperature in power amplifier.
Q115~118 Power AMP Detects over-current.
Q119~122 Power AMP Darlington driver.
Q123~126 Power AMP Darlington output.
Q131,132 ATT signal control Controls signal in attenuator.
Q201,202 Input mute Absorbs shook noise when power turns on or off.
Q203~206 Power AMP 1st deferential amplifier.
Q207~210 Power AMP 2nd deferential amplifier.
Q211,212 Power AMP Current mirror load for 2nd deferential amplifier.
Q213,214 Power AMP Compensates bias temperature in power amplifier.
Q215~218 Power AMP Detects over-current.
Q219~222 Power AMP Darlington driver.
Q223~226 Power AMP Darlington output.
Q231,232 ATT signal control Controls signal in attenuator.
Q601 B-class stage mute Generates mute signal. ON: Normal
Q602 Mute Generates mute signal. OFF: Normal
Q603 Input mute Generates mute signal. OFF: Normal
Q604 Power ON/OFF Controls primary power supply. ON: Normal
Q605 Power ON/OFF Controls power.
Q606 Power ON/OFF
Q610 Over-current DET Operates when Q610 detects over-current, and DC/DC converter turns off.
Q611,612 DC output voltage DET Operates when DC output voltage is in power amplifier.
Q613,614 DC output voltage DET Latch circuit for DC to be detected.
Q615,616 B-class stage mute Operates to turn off input of power amplifier.
Q617,618 B-class stage mute Drives Q615 and Q616. ON: Normal
D1 Wrong connection protection Cuts fuse off when connector is connected wrongly.
D2,3 AVR reference voltage Controls Q3 and Q4 with zener voltage.
D4,5 Secondary power supply rectifier
D6~10 Switching Prevents reverse flow.
D32~37 Static electricity protection Prevents OP-AMP to be broken by static electricity.
D101,102 Temperature compensator Stabilizes current between base and emitter of 2nd deferential transistors.
D103,104 Current mirror Current mirror load for 2nd deferential amplifier.
D105,106 B-class stage mute Prevents reverse flow.
D107~111 Over-current DET Prevents reverse flow.
D201,202 Temperature compensator Stabilizes current between base and emitter of 2nd deferential transistors.
Protects from over-voltage. Stops when primary power supply input voltage is below 16V.
3
KA C-6403
COMPONENTS DESCRIPTION
Ref. No Application / Function Operation / Condition / Compatibility
D203,204 Current mirror Current mirror load for 2nd deferential amplifier.
D205,206 B-class stage mute Prevents reverse flow.
D207~211 Over-current DET Prevents reverse flow.
D601 LED control Controls D610’s power indicator.
D602,603 Mute control Prevents reverse flow.
D604 Mute AVR 10V
D605 Power control Prevents reverse flow.
D606 Over-current DET Level shift for primary power supply.
D607 Power control Level shift
D608 Mute control Being controlled by Q602.
D610 LED Being controlled by Q602.
D613,614 DC protection Operates when DC is output.
D616 POP mute
ADJUSTMENT
No. Item Alignment Point Method Align for Note Fig.
Connect a DC voltmeter between
VR5 (A-Lch) the following emitter resistors.
1 IDEL CURRENT
4
VR6 (A-Rch) R253 (A-Lch)
VR7 (B-Lch) R254 (A-Rch) aging is required.
VR8 (B-Rch) R453 (B-Lch)
R454 (B-Rch)
2.5mV
Over 5 minutes
PC BOARD
on page 6
and 7.
A B C D E
C
R209
R
7
D
B
D
Q
Q
Q
Q211
KAC-6403
1
PC BOARD (FOIL SIDE VIEW)
AUDIO UNIT
X09-8542-70 (J76-0189-01)
B-Lch 2.5mV
DC voltmeter
2
3
4
J9
5
6
D1
C1
L3
R616
P1
791011
8
W190
5
6
3
4
R258
1
2
C224
W506
Q604
EB
W544
R612
R610
D607
W546
R614
R609
W545
R608
R611
D606
D605
BE BE BE BE
R613
D604
Q605
Q606
W543
R619
C602
W189
R458
C424
D603
R606
R607
Q603
BE
R605
D7
R257
W194
R604
D602
W195
R457
W188
C603
Q602
W187
R602
C423
D601
Q601
R615
D608
R11
R603
C223
R21
W192
C601
R10
Q6
W165
C10
L2
W191
W558
W542
W541
W178
W179
W184
W185
W186
C221
Q117
W902
W180
W181
W182
W183
BE
W540
R241
R255
W176
W177
Q5
R7
C8
W175
R251
W172
W167
W168
W169
W170
IDL-
R9
AL
R247
Q125
GSDGSD
C12
TH1
W166
W164
Q121
D4
R8
C9
D109
Q113
W163
W150
R237
C217
W158
W159
W160
W539
W162
W161
R231
EB
W157
R13
R12
W156
W203
R233
D5
R23
W557
R235
R28
W155
W202
VR5
R229
W154
Q9
C16
W153
AL
Q10
BEBE
C14
R24
W538
W592
W151
W152
W147
W148
W149
R243
R245
Q123
R22
R17
R16
D9
R18
R15
R14
R25
R20
BEBE
IC13
W537
Q8
W201
Q7
C15
R19
Q119
BE
D8
D6
916
81
R26
C6
2200uF
C7
2200uF
W143
W144
W145
W146
EEB
Q12
C17
C18
AL
IDL+
BE
C13
R27
W80
Q11
W141
W142
D107
W140
C219
R249
R239
R671
R618
D207
EB
C617
W138
R623
W139
Q115
R445
Q215
Q618
BE
R670
R622
W137
BL
IDL+
EB
R453
R449
C419
R439
TP44
W118
W128
W133
W124
W119
W125
W134
W129
R666
R669
R668
BE
R665
R667
D616
Q617
W120
W126
W135
W130
W131
W121
R620
R621
W122
W132
W127
W136
W123
R248
Q126
R253
EB
EB
Q219
W112
R443
R435
W534
W535
Q616
BEBE
Q615
W559
R661
R663
R662
R664
C606
W115
R629
BE
C610
Q610
D614
R632
C607
D613
R637
R634
BE
Q613
BE BE
Q612
W116
R635
Q611
W114
W113
W111
W91
W89
W117
D110
W90
Q122
W536
W101
W103
W196
W104
W105
W106
W107
W108
W97
W98
R633
BE
Q223
W102
R617
W110
BEBEBE
C609
R636
W109
EBB
Q213
VR7
BL
W94
W26
Q614
AR
IDL+
E
W78
W79
W99
W100
B
Q217
W93
C608
Q118
BE
R429
Q207
W198
R431
R261
C261
D105
W92
W96
R238
D111
R256
R252
C222
B
R441
C421
R425
R223
R225 R423
E
R242
I
W533
R455
C417
R433
R447
R451
R43
W83
EB
R419
Q209
BE
D201
R413
W85
R421
D203
C411
EB
W86
Q131
BE
R269
W578
BE
W579
Q111
D103
R221
W87
C211
R213
W88
D101
BE
BE
Q107
Q109
R219
W84
A-Lch
2.5mV
DC voltmeter
7
6
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