Kenwood KRC-21SYA, KRC-21SYG, KRC-21SG, KRC-266, KRC-266S Service Manual
©
2002-10 PRINTED IN JAPAN
B51-7982-00 (N)2139
KRC-21SA/SG/SYA/SYG (E type)
KRC-266/S (M type)
Mounting hardware assy
(J21-9701-03)
Plastic cabinet assy
(A02-1486-13)
Lever
(D10-3031-04)
x2
Depends on model. Refer to the parts list
Screw set
(N99-1610-15)
Screw set
(N99-1719-05)
KRC-21S
40W x 4
T.CALL
AUTO
AME
KRC-266
45W x 4
AUTO
AME
DC cord
(E30-4790-05)or
(E30-6134-05)
DC cord
(E30-4784-05)or
(E30-6131-05)
Antenna adaptor
(T90-0523-05)or
(T90-0534-05)
Panel assy (A64-2926-02)
Panel assy (A64-2915-02):KRC-266, (A64-2918-02):KRC-266S
Escutcheon
(B07-2188-02):KRC-21SA/SG/SYA/SYG, KRC-266
(B07-3021-02):KRC-266S
CASSETTE RECEIVER
KRC-21SA/SG/SYA/SYG
KRC-266/S
SERVICE MANUAL
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KRC-21SA/SG/SYA/SYG
KRC-266/S
2
BLOCK DIAGRAM
IC1
KEY
PAN 5V
MUTE
B.U. DET.
B.U.
ACC
P-CONT.
MUTE
PRE
POWER IC
EQ. AMP.
E-VOL.
CD/MD
CHANGER
FRONT Lch
FRONT Rch
REAR Lch
REAR Rch
J2
LCD DRIVER
LCD
CME1
MAIN
TAPE MECHA.
IC5
Lch
Rch
PRE OUT
IC2
IC4
IC3
SP OUT
REAR
J4
PAN IN SW
ACC DET.
P-CONT.
J2
J5
IC1
F/E
J1
FM+B
Q201
AM+B
Q203
AM BPF
FM BPF
C154,R206
C153,R207
Q320
Q450,451
Q49
Q50
Q350,351,370
Q53
SW 5V
Q54-57
8V
Q58-61
ILLUMI.
B.U. 5V
Q51,52
SYSTEM u-COM
S1
S2
S3
RST SW
Q301
D1-15
PL1,2
ANT.
ANT CONT
RST
ED1
FM ANT
AM ANT
RF GND
FM+B
AM+B
OSC GND
OSC GND
OSC GND
VT
PLL +B
IFC OUT
SDA
SCL
DIG GND
IF1+B
IF1 GND
S-METER
IF2 GND
SD
FM+B
P. O N
ACC DET
B.U. DET
SCL
MUTE
SDA
P CON
PANEL
HOLD
L CLK
L D ATA S
L D ATA L
FWD/REV
MOTOR
CH CON
DATA H
DATA C
REQ H
REQ C
CH CLK
Rch
COM
Lch
MP IN
AM
MPX
OUT RR
OUT LR
OUT RF
Rch
LEVEL
SCL
SDA
OUT LF
Rch
STBY
MUTE
Rch
Lch
T-MUTE
FWD
REV
B.U.5V
8V
B.U.
CH RST
S MUTE
8
5
10
B.U.5V
AM+B
VDD 5V
PACK IN
L RES
ANT CON
CH
MUTE
BEEP
SVR
AMP. STBY
SVR
AC GND (BEEP)
Lch Lch
Rch
Lch
1200mV
TAPE :1681mV
CD/MD-CH :3529mV
AM :546mV
FM :1781mV
8V
RF GND
OSC GND
IF2 +B
AUDIO OUT
8V
S-METER
SD
PLL-SCL
PLL-SDA
CM1
PLAY
HEAD
L/R
55.6mV
B.U.5V
SW 5V
8V
B.U.5V
AM: 170mV
FM: 400mV
TAPE
PACK IN
(FF/REW)
AMP. MUTE
FF/REW
B.U.5V
ILL
L CE
(X16)
A1
ANT CONT
D380
5V
R205
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KRC-21SA/SG/SYA/SYG
KRC-266/S
3
● SYNTHESIZER UNIT (X16-149x-xx)
COMPONENTS DESCRIPTION
Ref.No.
Application/Functions Operation/Condition/Compatibility
IC1 LCD driver with key-matrix
Q1 Key-matrix permission SW Ready on key-matrix
● SYNTHESIZER UNIT (X14-685x-xx)
Ref.No.
Application/Functions Operation/Condition/Compatibility
IC1 System MI-COM. System control
IC2 E-VOL. & N.C. MPX Controls sound volume. Selects each source.
IC3 Mute logic 3-input NOR gate x 3
IC4 Power IC Amplifies power so that the speaker can drive audio signal.
IC5 Equalizer amplifier Equalizer amplifier for cassette tape sound
Q50
BACK-UP detection(Momentary
power down detection) SW
While BACK-UP is added, a base becomes Hi, and Q50 is turned on.
Q51
BACK-UP 5V AVR
While BACK-UP is added, AVR outputs +5V.
Q52
Q51 and Q52 is inverted Darlington connection.
Q53 P.ON 5V SW While a base becomes Lo, Q53 is turned on.
Q54
COM+B SW
While Q54's base becomes Hi, Q55 is turned on.
Q55
Works during POWER ON mode.
Q56
COM+B AVR
While Q57's base becomes Hi, Q56 is turned on.
Q57
Q56 and Q57 is inverted Darlington connection.
Q58
Illumination +B SW
While Q58's base becomes Hi, Q59 is turned on.
Q59
Works during POWER ON mode with a panel attached to the set.
Q60
Illumination +B AVR
While Q61's base becomes Hi, Q60 is turned on.
Q61
Q60 and Q61 is inverted Darlington connection.
Q150 Electric volume mute SW
When BACK-UP detection SW or CHANGER RESET SW or MI-COM.'s mute
works, a base becomes Hi, and Q150 is turned on.
Q151 SVR discharge SW When POWER IC RESET is activated, a base becomes Hi, Q151 is turned on.
Q153 Pre-out mute driver
When BACK-UP detection SW or CHANGER RESET SW or MI-COM.'s mute
works, a base becomes Lo, and Q153 is turned on.
Q200
FM +B SW
Q201 is turned on when Q200's base becomes Hi.
Q201
Works during FM reception mode.
Q202
AM +B SW
Q203 is turned on when Q202's base becomes Hi.
Q203
Works during AM reception mode.
Q260
Motor +B SW When Q260's base becomes Hi, Q261 is turned on. Works during TAPE mode.
Q261
Q301 Changer reset SW When a base becomes Lo, Q301 is turned on.
Q320 Panel 5V SW While a panel is attached to the set, a base becomes Lo, and Q320 is turned on.
Q350 P-CON. driver When Q353's base becomes Hi, Q350 is turned on.
Q351 P-CON. protection SW Works when P-CON is being short-circuited on GND.
Q352 P-CON. protection inhibit SW Inhibits protection SW function when P-CON works momentary.
Q353 P-CON. SW Q353 is turned on when a base becomes Hi. Works during POWER ON mode.
Q370
ANT-CON. SW Q370 is turned on when Q371's base becomes Hi.Works during TUNER mode.
Q371
Q450 Pre-out mute SW (R ch.) When BACK-UP detection SW or CHANGER RESET SW or MI-COM.'s mute
Q451 Pre-out mute SW (L ch.) works, a base becomes Hi, and Q450,451 are turned on.
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KRC-21SA/SG/SYA/SYG
KRC-266/S
4
MICROCOMPUTER'S TERMINAL DESCRIPTION
● SYSTEM MICROCOMPUTER LC72366-9592 (IC1 : X14-685x-xx)
Pin No.
Pin name I/O Description
Processing Operation
1 XIN I Main clock resonator connection terminal
2 GND - TEST terminal 2 Connected to GND lines.
3 L DATA L I Data input from the LCD driver IC
4 L DATA S O Data output to the LCD driver IC
5 L CLK O Clock output to the LCD driver IC
6 L CE O CE output to the LCD driver IC
7 SDA I/O Data input/output with the E-VOL. IC
8 PLL DATA I/O Data input/output with the F/E
9 PLL CLK O Clock output to the F/E
10 SD I SD input from the F/E Hi : Station detected
11 DATA C I Data input from changers
12 DATA H O Data output to changers
13 CH CLK I/O Clock input/output with changers
14 - O - N.C. (Not used)
15 MOTOR O Cassette motor on/off output Hi : Motor ON
16 SCL O Clock output to the E-VOL. IC
17-24 - O - N.C. (Not used)
25 AM+B O AM+B ON/OFF output Hi : during AM reception
26 FM+B O FM+B ON/OFF output Hi : during FM reception
27 PACK IN I Cassette tape Pack-in detection input Lo : Pack-in
28 FF/REW I FF/REW detection input Lo : FF/REW, Hi : PLAY
29 GND I - Connected to GND lines.
30 GND I - Connected to GND lines.
31 VDD - Positive power supply connection terminal Connected to B.U. 5V lines.
32 REQ C I Request input from changers Lo : Request
33 MUTE O Audio mute on/off output Hi : Mute ON
34 CH CON O Changer control Lo : Standby, Hi : ON
35 REQ H O Request output to changers Lo : Request
When the momentary power down, after ACC
36 SVR O Power IC reset terminal ON/OFF is detected and after POWER OFF,
the output becomes Hi temporarily.
37 AMP STBY O Power IC standby control output Hi : POWER ON mode
38 AMP MUTE O Power IC mute control Lo : Mute
39 P CON O Power control Hi : POWER ON mode
40 ANT CON O Antenna control Hi : during FM/AM reception
41 SW5V O SW 5V control Lo : POWER ON mode
42 ILL O Illumination AVR ON/OFF control terminal Hi : POWER ON mode
43 - O - N.C. (Not used)
44 BEEP O BEEP sound output
45-47 - O - N.C. (Not used)
48 ROLL OFF I Roll off input Pull down to GND lines. (Not used)
49
NOISE
CANCELLER
I Noise canceller input Pull down to GND lines. (Not used)
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KRC-21SA/SG/SYA/SYG
KRC-266/S
5
MICROCOMPUTER'S TERMINAL DESCRIPTION
● SYSTEM MICROCOMPUTER LC72366-9592 (IC1 : X14-685x-xx)
Pin No.
Pin name I/O Description
Processing Operation
50 SEL1 I Destination input 1 Hi : KRC-21S
51 SEL2 I Destination input 2 Hi : KRC-21S
52 SEL3 O Destination input 3 N.C. (Not used)
53 EQ MUTE O Tape equalizer mute on/off output N.C. (Not used)
54 FWD/REV I FWD/REV mode detection input Lo : REV mode
55 - O - N.C. (Not used)
56 REMO I
Data input from the remote control
N.C. (Not used)
light sensor
57-60 - O - N.C. (Not used)
61 ACC DET I ACC detection input Hi : ACC ON
62 B.U. DET I Momentary power down detection input
Hi : When momentary power down detected or
B.U. OFF, Lo : B.U. ON
63 S METER I S-meter input from the F/E
64 PANEL I Panel detaching detection input Lo : Panel not detached
65 GND I - Connected to GND lines.
66 GND I - Connected to GND lines.
67 HOLD I MI-COM. HOLD input Lo : Hold
68 VDD - VDD connection terminal Connected to B.U. 5V lines.
69 GND I - Connected to GND lines.
70 GND I - Connected to GND lines.
71,72 - O - N.C. (Not used)
73 VDD - Positive power supply connection terminal Connected to B.U. 5V lines.
74 GND I - Connected to GND lines.
75 GND I - Connected to GND lines.
76 VSS - Ground connection terminal Connected to GND lines.
77,78 - O - N.C. (Not used)
79 GND - TEST terminal 1 Connected to GND lines.
80 XOUT O Main clock resonator connection terminal
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ADJUSTMENT
(2-LINE TAPE)
B
A
B
A
(FWD)
(RVS)
HEIGHT
(FWD)
HEIGHT/AZIMUTH
(FWD)
HEIGHT/AZIMUTH
(RVS)
TAPE SPEED
HEIGHT
(RVS)
F
''
F
R
R
No ITEM
INPUT SETTINGS
RECEIVER
SETTINGS
ALIGNMENT
POINTS
ALIGN FOR
SD
SD
HEAD
HEIGHT
HEAD
AZIMUTH
TEST MODE : ON While holding the "FM" key and preset "6" key, reset the unit.
TEST MODE : OFF Reset the unit.
98.1MHz
0 dev
35dBµ(ANT input)
990 kHz
0% mod
35dBµ(ANT input)
SCC-1659
TCC-153
10kHz
TEST MODE: ON
FM
98.1MHz
TEST MODE: ON
AM
990 kHz
TAPE PLAY
Connect an AC
voltmeter and
oscilloscope to
SP outputs.
TAPE PLAY
Preset "1" key,
and
preset "6" key
Preset "1" key,
and
preset "6" key
Head Height Screw
Head
Azimuth
Screw
While holding preset "1" key, press and hold preset "6" key
for a few seconds.
"1111" is good.
"0000" is not good.
While holding preset "1" key, press and hold preset "6" key
for a few seconds.
"1111" is good.
"0000" is not good.
1) During FWD transport adjust
⁄F and ⁄F ' so that line A of 2-
LINE TAPE passes through the center of the head shield
plate (core center area)
2) During RVS transport adjust ⁄
R and ⁄R ' so that line B of 2-
LINE TAPE passes through the center of the head shield
plate (core center area)
3) After the alignment above, reverse the transport direction
and check the FWD alignment again. If it is deviated, perform
alignment again.
(Tape used : SCC-1659,manufactured by A-BEX)
Adjust the azimuth for each L ch/R ch or FWD/RVS
becomes maximum.
1
(1)
[1]
[2]
FM SECTION
AM SECTION
CASSETTE DECK SECTION
KRC-21SA/SG/SYA/SYG
KRC-266/S
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A B C D E
1
2
3
4
5
6
7
AM
FM
AUD
PL1
RST654321
PL2
ATT
CLIKAUTO
SRC
129
D2
D1
D4
D3
D5
D6
D7
D8
D9
D10
D11
D12
D14
D15
D13
X16-149x-xx (J74-1298-02)
PC BOARD
Refer to the schematic diagram for the values of resistors and capacitors.
(COMPONENT SIDE VIEW) (FOIL SIDE VIEW)
7
X16-149x-xx (J74-1298-02)
R13
R14
R18
R8
R11
R12
R19
C4
C2
C1
C5
R3
R4
R2
R1
R21
R20
R5
R6
C6
6449
48
12
33 16
1
1732
11
1
2
EB
Q1
IC1
D17
J1
Ref. No.
address
IC1 3D
Q1 4D
X16-149x-xx
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F G H I J
1
2
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PC BOARD
(FOIL SIDE VIEW)
W100
W75
W85
W73
W67
W72
W65
W96
W68
W64
W71
W69
W79
W76
W98
W99
R50
R65
R351
R353
R66
X1
C50
C55
C161
C350
C352
C162
C56
C58
C53
C57
W94
W95
W101
W54
C4
C3
C9
C250
C10
W92
W70
W59
W87
W80
W97
W93
W89
W88
W103
W86
W90
W78
W56
W82
W83
W74
W81
W77
W63
W102
W57
W60
W62
W84
L1
4.5MHz
R55
R67
R350
R370
R371
R373
C320
R138
R132
916
18
25
24
1
5
1
8
111
122
E
B
B
E
BE
B
E
B
E
(J74-1317-12)
CN1
Q60
Q56
D352
Q51
Q350
D56
D52
D51
D55
D54
D350
D351/W104
D53
IC5
J2
J3
D370
IC4
D50
Q370
D371
D151
D152
D100
X14-685x-xx
W122
R58
R155
R15
R62
W113
R129
R59
W121
R372
R151
C101
C600
R324
R115
R52
R54
R352
R320
R154
R303
R304
R306
R305
R321
W129
C54
R63
R64
R57
C52
C1
C2
C6
C5
C7
C8
R6
R7
R5
R2
R3
R4
C14
R8
C13
R1
C251
R251
R323
W131
W125
C102
C103
W128
W130
R160
W118
R158
R156
R250
R137
W120
R122
R120
R121
R123
R111
R109
W126
R110
W127
R108
W132
C351
EB
1
80
64
25
40
24
41
65
BE
BE
EB
BE
EB
EB
EB
EB
EB
EB
BE
EB
BE
BE
Q61
Q52
Q371
Q59
Q58
Q57
Q55
Q54
Q53
Q50
Q353
Q301
Q320
Q352
Q351
IC1
Refer to the schematic diagram for the values of resistors and capacitors.
Ref. No.
address
IC1 5J
IC5 5H
Q50 4I
Q51 4I
Q52 4H
Q53 4H
Q54 4H
Q55 3H
Q56 2G
Q57 3H
Q58 4H
Q59 4H
Q60 3G
Q61 3G
Q301 6I
Q320 6I
Q350 4J
Q351 4J
Q352 4J
Q353 4I
Q370 3J
Q371 4J
X14-685x-xx
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