Kenwood KRC-28 Service manual
CASSETTE RECEIVER
DC CORD
(E30-4790-05)
ANTENNA ADAPTOR
(T90-0523-05)
LEVER
(D10-3031-04)x2
MOUNTING HARDWARE ASSY
(J21-9491-03)
PLASTIC CABINET ASSY
(A02-1486-13)
KRC-28YG/YA
SERVICE MANUAL
PANEL ASSY
(A64-1909-02)
CASSETTE LID
(A53-1638-13)
© 1999-11 PRINTED IN JAPAN
B51-7546-00 (N) 1580
MECHANISM EXTENSION CORD
W05-0477-00 (7P)
W05-0609-00 (10P)
KRC-28
LOUD
FRONT GLASS
(B10-3140-01)
B.S REP
T.CALL
ESCUTCHEON
(B07-2181-02)
EJECT
40W 4
A.ADJ
X
AUTO
AME ADJ
CLK
PWR
OFF
SRC
MONO
KRC-28YG/YA
A1
SYSTEM u-COM
IC1
DSI
KEY
PANEL
RST SW
PAN 5V
B.U. 5V
MUTE
ACC DET
B.U. DET
ILLUMI AVR
MUTE DRIVER
PRE MUTE
POWER IC
IC6
EQ AMP
E-VOL
4ch
SP OUT
WITH
LCD DRIVER
LCD
MAINSUB
IC5
ON/OFF
IC2
IC4
SVR SW
ANT-CON
P.ON 5V
PRE OUT
TEL-MUTE
ANT-CON
P-CONT
ACC
B.U.
KEY MATRIX
MM
Q201
IC7
Q121
Q87-89
Q80,81
Q101
Q118
Q94-96
Q116,117
J5/6
J2
Q41-44
Q104
IC1
Q105
J1
ANT
FM ANT
AM ANT
AUDIO OUT
PLL
S METERS-METER
PLL DATA
SUB+
SUB-
ACC
B.U.
AMP MUTE
SCK
PWR STBY
SDA
FM +B
AM +B
RST
PANEL ON/OFF
LCD CLK
LCD CE
LCD DATA OUT
LCD DATA IN
DSI
FWD/REV
T MODE
PACK IN
MOTOR
OUT
Rch
COM
Lch
TAPE
L/R
MPX
AM
OUT RR
OUT LR
OUT RF
LEVEL
SCK
SDA
OUT LF
TAPE L/R
STBY
MUTE
Rch
Lch
PACK
T-END
STBY
MODE
FWD
REV
B.U. 5V
COM+B
B.U. 14V
S MUTE
168mV
162mV
E:190mV
KM:360mV
(AM)
(FM)
E:1100mV
KM:1600mV
(TAPE)1708mV
(FM)
(CD-CH)3635mV
615mV
830mV
(AM)
780mV
570mV
(CD-CH)3495mV
(AM)(FM)
KM:1500mV
E:1060mV
(TAPE)1642mV
5
10
IN
HD1
FM+B
AM+B
COM+B
B.U. 5V
PLL CLK
SUB
MOTOR
MP IN
SVR
PHONE
ILL ON
B.U. 5V
P.ON 5V
REMOTE
341mV
SVR
Ref.102
Ref.103
Ref.95
Ref.105
Ref.94
M2 M1
8V AVR
Q84,85
COM+B
FM+B
AM+B
Q93
Q92
P-CON
BLOCK DIAGRAM
2
KRC-28YG/YA
CIRCUIT DESCRIPTION
(X14-) IC1 : SYSTEM u-COM
PORT
PORT NAME
No.
1 XIN I Clock input
2 TEST 2 - GND
3 LCD DATA IN I LCD driver data input
4 LCD DATA OUT O LCD driver data output
5 LCD CLK O LCD driver clock output
6 STBY I Tape stand-by SW
7 T END I Tape end SW
8 SDA 2 I/O Data line to E-VOL.
9 SCL 2 O Clock line to E-VOL.
10 REQ H O Changer request output
11 DATA C I Changer data input
12 DATA H O Changer data output
13 CH CLK I Changer clock input
14 REQ C I Changer request input
15 CH CON O Changer control
16 LCD CE O LCD driver Chip Enable output
17 AM+B O AM power supply control
18 FM+B O FM power supply control
19 MUTE O Mute output for audio circuit
20 ILLUMI O Illumination on
21 AMP STBY O
22 SVR O SVR discharge circuit control
23 P.CON O Power control
24 ANT CONT O Tuner ANT control
25 SUB+ O Sub motor+output
26 SUB- O Sub motor-output
27 - - 28 SEL 2 I Destination discrimination 2
29 SEL 1 I Destination discrimination 1
30 SEL 0 I Destination discrimination 0
31 VDD - VDD
32 N.CAN I Noise canceller setting
33 MOTOR O Motor-ON output
34-
---
36
37 DSI O Disable System Indicator
38 EQ MUTE O Tape equaliser mute output
39 P.ON O Power on
40 - - -
I/O
Stand-by output to power amp
FUNCTION
(X14-) IC1 : SYSTEM u-COM
PORT
PORT NAME
No.
41 - - 42 MS CONT O 43 - - 44 BEEP O Beep output(2.08KHz)
45 PANEL I Panel ON/OFF detection
46 AMP MUTE O Mute
47 CRSC I 48 PACK IN I Pack-in detection
49 FWD/REV I Tape FWD/REV
50 SDA3 O PLL/EEPROM data line
51 SCL3 O PLL/EEPROM clock line
52 METAL O Metal mode ON/OFF
53 DOLBY O Dolby
54 AM IF CONT I AM IF count judgement
55 SD I SD input
56 REMOTE I Remote controller
57-
---
60
61 T MODE I Mode pulse input
62 PHONE I Telephone mute input
63 ACC I ACC detection
64 BACK UP I Back Up detection
65 MUSIC I Tape signal detection
66 S-METER I FM band SD detection
67 HOLD I Hold Detection
68 SNS I 69 LCTR - GND
70 HCTR - GND
71,
---
72
73 VDD - VDD
74 AM IN - GND
75 FM IN - GND
76 VSS - GND
77,
---
78
79 TEST1 - GND
80 XOUT I Clock output
I/O
FUNCTION
3
KRC-28YG/YA
BALANCE/FADER/BASS/TREBLE:CENTER
T.ADV/METAL/DOLBY NR/AUTO:OFF
ADJUSTMENT
No. ITEM
CASSETTE DECK SECTION
1 AZIMUTH
INPUT
SETTINGS
TCC-153
10KHz
OUTPUT
SETTINGS
SP OUT TAPE PLAY
RECEIVER
SETTINGS
ALIGNMENT
POINTS
Head azimuth
screw
(FWD/REV)
(ME1)
ALIGN FOR FIG.
Adjust so that output
level in playing “FWD”
and “REV” becomes
maximum each.
(b)
(b) AZIMUTH
FWD
F/E
REV
FRONT
4
A B C D E F G H I J
R40
R46
R104
R122
R258
R39
R47
R24
R27
R123
R45
R338
R14
W2
R23
R22
R21
W1
C122
C102C101
TH1
R48
R54
R124
R177
C43
R412
R55
R3
R4
C2
R2
C1
R1
R58
C104
C59
R13
R11
R182
C131
R179
R178
R12
R413
R50
C125
R196
R156
R52
C337
C336
C56
R62
R157
R51
C61
R71
R90
C132
R187
R419
C57
C81
R70
C66
R186
C111
R341
C105
R101
R106
R107
R143
R102
R256
R42
R129
R340
R339
R105
W3
R103
R336
R59
R53
B
E
BE
BE
EB
EBEB
BE
BE
BE
BE
BE
Q88
Q96
D5
D4
D3
Q83
Q85
D7
D1
Q87
Q119
Q118
Q91
Q82
Q81
Q89
D84
CMP
L
GLR
DOLBY
R
(4.50)
L1
W26
C80
L7
W35
W30
W17
W18
W13
W21
W20
W37
C46
C18
C17
W34
C16
C15
W12
W25
W33
W32
W31
W29
R29
C110
L3
L2
C65
C86
C88
C203
C12
VR2
R337
C11
W28
W36
W22
W27
C48
R175
C8
R77
W15
W14
W23
R65
C170
W24
R26
W38
C45
VR1
L6
C124
X1
C208
C3
C123
C126
C4
C47
L5
C83
C205
X86
C82
C7
C13
C67
C127
C55
C204
C128
C84
R63
R64
C85
C202
C212
1576109
2348
121311
1
916
8
1
25
2
24
1
13
23
1
10
1
2
1
2
15
14
1
7
R191
R255
W5
R404
R418
R416
R180
R407
R406
R405
R417
CP4
C87
R192
R411
R408
R410
R409
C193
R30
R28
R8
R6
R257
R5
R44
R38
R37
R43
R41
R250
R36
R35
R33
R34
R125
C211
R127
CP2
CP3
CP1
C194
C195
C68
C6
R10
R251
R119
R120
R121
C54
R25
C5
R7
R9
R135
R195
R193
R184
R149
R176
R194
R415
C133
C69
C70
R67
R153
R154
C19
C20
R185
R207
R61
R114
R414
R126
R60
R56
R57
C60
R253
R142
R146
R145
28 15
141
17
814
1
10
11
20
21
30
31
40
1
5
6
10
1
24
25 40
41
60
6180
B
E
E
B
E
B
B
E
E
E
B
E
B
B
B
E
EB
E
B
B
E
B
EB
E
BE
BE
EB
B
B
E
EB
E
E
B
B
B
E
B
E
E
EB
X14-6162-71
D16
CN1
D17
D85
D332
D81
J4
Q94
Q336
D20
Q92
D86
J6
D408
D411
Q117
D333
Q80
J2
CN2
D83
CN5
D90
D19
D21
IC4
Q93
J3
D80
D18
J5
D82
CN4
J1
PRE OUT
IC2
Q41
D403
D6
Q44
Q95
IC6
IC1
Q97
Q43
Q42
Q116
IC7
Q335
Q90
IC5
Q201
Q121
Q103
D8
Q101
Q86
Q84
Q337
Q105
Q104
D11
PC BOARD (COMPONENT SIDE VIEW)
1
X13-9672-7X
2
3
4
5
6
7
D1
ATT
RST
1
D4
2
D5
3
D6
17 32
16
4
1
D7
64
D24
5
D25
D8
R12
R11
6
R3
D9
15
AUTO
D10
1
CLK
R13
D11
VOL.
DOWN
R4
R2
C4
C1
C5
R19
R14
14
2
AM
IC1
R18
R6
D22
C2
R22
C6
D2
C7
Q1
BE
D15
D14
R16
49
33
48
D21
D3
1
24
25
38
FM
D16
R1
D26
VOL.
UP
C3
R17
43
IC2
12
address
IC Q
14A
22B
14A
D12
EJECT
D13
AUD
R5
R7
C8
D17
SRC
IC Q
address
16E
24G
41F
55G
66H
74F
41 3H
42 3H
43 3H
44 3H
80 4C
81 4C
82 5E
83 5F
84 5E
85 5E
86 6D
87 6D
88 6C
89 6C
90 3H
91 3H
92 3H
93 4H
94 4C
95 4D
96 4D
97 4D
101 5F
103 5F
104 6F
105 7E
116 4C
117 4C
118 4E
119 4G
121 4G
201 3G
335 6C
336 6C
337 6D
Refer to the schematic diagram for the values of resistors and capacitors.
5 6
K L M N O P Q R S T
1
R6
R4
C6
2
C8
R7
R5
R13
15
R3
R11
R12
14
R14
64
1
49
R18
R19
C2
C4
C1
C5
BE
48
16
17
33
32
R16
R2
C7
R17
C3
R1
R22
D25
D24
IC1
Q1
D26
AM
FM
CLK
AUTO
SRC
AUD
6
5
4
EJECT
3
2
1
RST
21
34
ATT
DOWN
VOL.
VOL.
UP
D11
D14
D16
D10
D15
D21
D17
D13
D9
D7
D8
D12
D6
D5
D4
D22
IC2
X13-9672-7X
D1
D2
D3
38
25
24
1
1
2
3
4
5
6
7
PC BOARD (FOIL SIDE VIEW)
address
X86
IC Q
14L
22K
14L
Refer to the schematic diagram for the values of resistors and capacitors.
J1
L7
CN4
1
2
X14-6162-71
PRE OUT
R154
B
Q101
D18
R186
R129
R103
C133
E
R57
E
C204
C132
R187
W5
TH1
R180
CP2
CP3
C60
1
W17
CP4
R127
R56
R149
Q83
BE
W18
IC7
R143
R101
R102
CP1
W38
W22
W25
W24
W23
1
D16
L1
W1
W29
W30
W36
W37
W27
W26
D19
148
R179
R178
R182
17
C131
EB
C85
Q118
C84
R62
R61
D21
R146
61
60
C111
R60
Q84
BE
Q82
80
BE
Q85
C102C101
1
IC1
R418
R123
R105
R104
41
40
R121
R120
R124
R119
R417
R419
24
25
R126
R125
EB
IC4
24 2
25
R195
R194
1
10
Q43
R54
C336
R47
E
R41
B
C18
C212
C2
C1
R55
C337
Q41
R2
R1
C123
10
J3
J6
R43
R37
E
R45
R90
R156
R38
B
R39
C17
L3
C4
C3
IC6
E
R59
Q44
B
R46
C16
C211
CMP
R6
R7
R157
R44
B
R40
E
R5
C61
R256
R48
Q42
C193
C69
R8
C6
C56
1
56
C205
C202
R42
15
14
C70
C194
40
R3
31
C5
R53
14
D7
Q119
R4
R10
1
30
R52
15
R9
C203
R257
EB
R58
IC5
C55
R33
R67
R35
C45
C15
C66
C195
10
21
C57
R34
R36
IC2
R192
R191
C68
11
20
W12
W13
C48
C46
C47
C59
C54
R51
D332
C19
C126
C170
28
1
C20
C124
C128
C67
E
B
Q121
R50
Q201
R255
C125
EB
R258
C65
D6
R207
R253
C127
R65
R135
R250
W14
R251
Q103
W21
W20
W15
L5
R153
EB
Q104
B
J5
C43
D1
L6
Q92
E
B
E
Q90
1
B
BE
Q91
R193
R196
E
B
Q93
R12
L
1
C8
R14
C7
VR2
R
VR1
CN5
L
1
D90
L2
CN1
2
C208
DOLBY
R3G
23
R11 R13
R122
R176
W31
W28
R28
BE
R184
D11
D84
W32
Q105
J2
W33
R64
(4.50)
X1
R341
C105
R416
D85
D86
E
B
Q97
Q337
R185
W35
W34
R175
D17
R24
R27
C88
B
R63
D82
R145
R142
R107 R338
E
R106
C104
B
R339
Q86
B
E
R114
D8
R411
E
R30
R340
169
8
D20
R177
C122
Q95
Q96
C83
C110
R409
C87
R414
Q87
R410
D3
R29
D80
B
W2
23481213
R406
R408
R21
R23
C13
C11
D5
E
C86
B
Q80
C82
R412
R413
Q89
BE
E
D4
R415
Q94
E
B
B
E
R405
B
E
R77
Q88
J4
R407
R22
C12
BE
CN2
610715
R404
Q117
B
E
Q81
R71
Q116
E
B
7
1
D83
BE
11
9
D408
D411
D403
R26
R70
C81
D333
Q335
W3
R25
D81
Q336
R337
B
E
C80
R336
IC Q
address
16Q
24O
41P
55O
66N
74Q
41 3N
42 3O
43 3N
44 3O
80 4S
81 4S
82 5Q
83 5P
84 5Q
85 5R
86 6R
87 6R
88 6S
89 6S
90 3N
91 3N
92 3N
93 4N
94 4S
95 4R
96 4R
97 4R
101 5P
103 5P
104 6P
115 7R
116 4S
117 4S
118 4Q
119 4O
121 4P
201 3P
335 6S
336 6S
337 6R
13 14
Loading...