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© 2002-10 PRINTED IN JAPAN
B51-7986-00 (N) 2139
CASSETTE RECEIVER
KRC-31Y/36/366L/37/37Y
/391/394/394Y/466R
/4904Y
SERVICE MANUAL
Mechanism extension cord : W05-0477-00 (7P), W05-0609-00 (10P)
LOUD
SCRL
SCAN
REP
T.CALL
M.RDM
B.S/RDM
MENU TI
VOL ADJ
CLK
KRC-XXXX
SRC
OFF
45Wx4
AUD
DISC
LOUD
SCRL
SCAN
REP
T.CALL
M.RDM
B.S/RDM
MENU
AUTO
AME
CLK
KRC-XXXX
SRC
OFF
45Wx4
AUD
DISC
LOUD
SCRL
SCAN
REP
T.CALL
M.RDM
B.S/RDM
MENU
AUTO
AME
CLK
KRC-4904
SRC
OFF
45Wx4
AUD
DISC
KRC-36/37/37Y
/391/394
/394Y/466R
Mounting hardware assy
(J21-9716-03)
Plastic cabinet assy
(A02-1486-13)
Screw set
(N99-1610-15)
Lever
(D10-4589-04) x2
Antenna adaptor
(T90-0523-05)
DC cord
(E30-4792-05)
Depends on model. Refer to the parts list.
Screw set
(N99-1719-05)
WIDE BAND
KRC-31Y/366L
KRC-4904Y
Panel assy
KRC-391:
(A64-2538-02)
KRC-36:
(A64-2541-02)
KRC-466R:
(A64-2941-02)
KRC-394/394Y:
(A64-2945-02)
KRC-37/37Y:
(A64-2947-02)
Panel assy
KRC-366L:
(A64-2942-02)
KRC-31Y:
(A64-2946-02)
Panel assy
(A64-2948-02)
Escutcheon
(B07-)


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KRC-31Y/36/366L/37/Y
/391/394/Y/466R/4904Y
2
BLOCK
DIA
GRAM
FM ANT
AM ANT
RF GND
FM+B
AM+B
AM LO/DX
FM LO/DX
IF SELECT
RDS OUT
FM SD OUT
REQUEST
K2I-VTH
VCO-GND
FSD OUT
FM DET OUT
AM DET OUT
IF GND
COMMON+B
P-ON 5V
DIG GND
PLL DATA
PLL CLK
PLL CE
HI UP ADJ
FM+B
AM+B
A8V
SW5V
LO/DX
SD
S-METER
PLL-DATA
PLL-CE
SW5V
ACC-DET
BU-DET
SCL
MUTE
SDA
EN1
EN2
EN3
P
ANEL
RESET
DSI
CH
MUTE
NOISE
D
ATA
H
D
ATA
C
REQ
H
REQ
C
CH
RST
CH
CON
CH
CLK
Rch
COM
Lch
TAPE L/R
MP IN
AFS
QUAL
AM
MPX
OUT RR
OUT LR
OUT RF
LEVEL
SCL
SW5V
SDA
SCL
SD
A
OUT LF
STBY
MUTE
SMUTE
5
10
BU5V
AFS
R QUAL
R CLK
R DATA
BU5V
REMO
SW5V
GREEN
RED
BU5V
PHONE
BEEP
SVR
P-MUTE
P-STBY
SVR
AC GND(BEEP)
T
APE
L/R
PLL-CLK
SW5V
L-RES
L-CLK
L
-D
ATA
S
L
-D
ATA
L
MUSIC
EQ-MUTE
MS-CONT
MUSIC
EQ-MUTE
MS-CONT
FWD/REV
P
A
CK
IN
M-STBY
T
-MODE
T
-END
L-CE
340mV
SUB+
SUB-
Rch
Lch
PACK
T-END
M-STBY
T-MODE
FWD
REV
AUDIO
8V
MOTOR
BU14V
SW5V
IN
PLAY HEAD
SW5V
BU14V
BU5V
BU14V
EN1
EN2
EN3
P,CON
ILLUM
B.U.5V
AM+B
AUDIO
FM+B
FM+B
AM+B
AUDIO 8V
AUDIO 8V
AUDIO 8V
BU5V
SW5V
TAPE
CD-CH
AM
FM
: 1719mV
: 3424mV
: 550mV
: 1727mV
TAPE
CD-CH
AM
FM
: 1786mV
: 3546mV
: 850mV
: 1345mV
AM : 160mV
FM : 213mV
CD L/R
1200mV
BU14V
CD L/R
8
RDS
ANT.
DECODER
SYSTEM u-COM
KEY
PAN 5V
MUTE
E2PROM
EQ AMP
CD ISO AMP
E-VOL
LCD DRIVER
LCD
DSI
REMO
RST SW
PAN IN SW
GREEN
RED or
RST IC
TEL DET
TEL MUTE
DRIVER
MAIN
SUB
AVR
SW5
B.U. DET
SURGE-DET
B.U.
ACC
P-CONT
DC CONNECTOR
REGULATOR
ACC DET
J2
VOLTAGE
MUTE
PRE
R-Lch
R-Rch
AMP
SVR
MUTE
THERMO
PROTECTION
FRONT Lch
FRONT Rch
REAR Lch
REAR Rch
IC4
J4
POWER IC
TDA7386
CD/MD
CHANGER
SP OUT
J5
PRE OUT
IC10
SUB MOTOR
DRIVER
MOTOR
DRIVER
IC1
IC2
IC12
IC9
IC2
IC1
IC11
IC7
IC8
Q2,3
IC6
TUNER
(X16)
(X14)
M
M
TAPE MECHA


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KRC-31Y/36/366L/37/Y
/391/394/Y/466R/4904Y
3
COMPONENTS DESCRIPTION
q SYNTHESIZER UNIT (X14-689x-xx)
Ref. No.
Function
Operation
IC1
System
µ-com
IC2
E-volume
IC4
Power amplifier
Speaker output.
IC6
RDS decoder
IC7
Power IC
IC8
Mute control logic
3 input NOR gate x 3.
IC9
Equalizer amplifier
For full logical cassette mechanism control.
IC10
Sub motor driver
For full logical cassette mechanism sub motor driver.
IC11
Reset IC
Detection voltage below 3.0V.
IC12
EEPROM
Q1
P. CON detection
Detects P.CON voltage.
Q10
Backup detection
Detects the backup voltage.
Q11
Surge detection
Detects surge voltage.
Q20
ACC detection
Detects ACC voltage.
Q40
Preout mute driver
Mutes when the base terminal voltage level becomes "L".
Q50
5V SW
Works when the base terminal voltage level becomes "L".
Q101
DSI SW
LED for DSI works when the base terminal voltage level becomes "H".
Q151
Panel 5V SW
Works when the base terminal voltage level becomes "L". Supplies VDD to panel.
Q201
Noise detection
Detects noise.
Q221~224
Preout mute
Mutes when the base terminal voltage level becomes "H".
Q251
Power IC SVR SW
Discharges the capacitor's voltage of SVR terminal after the base terminal voltage becomes "H".
Q301
Local seek SW
Changes to the local seeking after the base terminal voltage becomes "H".
Q501
Motor driver AVR
Works when the base terminal voltage becomes "H". Supplies the power to the motor driver.
Q551
Main motor SW
Works when the base terminal voltage becomes "L".
Q552
Main motor SW
Works when the base terminal voltage becomes "H".
q SWITCH UNIT (X16-1532-7x)
Ref. No.
Function
Operation
IC1
LCD driver
IC2
Remote sensor
Q1
Key scan SW
Receives key signal when the base terminal voltage becomes "L".
Q2
Key illumination SW
Key illumination color becomes green when the base terminal voltage becomes "H".
Q3
Key illumination SW
Key illumination color becomes red when the base terminal voltage becomes "H".


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KRC-31Y/36/366L/37/Y
/391/394/Y/466R/4904Y
4
MICROCOMPUTER'S TERMINAL DESCRIPTION
q Microcomputer : UPD780058GCxxx (X14 : IC1)
Pin No.
Pin Name
I/O
Function / Operating Condition
1
DSI
O
DSI control.
2
PANEL
I
Panel detection. "L" : Panel exists
3-
-
-
4
AVSS
-
GND.
5
L-RST
O
LCD driver reset.
6
L-CE
O
LCD driver chip enable.
7
AVREF1
I
Reference voltage.
8-
-
-
9
PLL-DATA
I/O
Front-end communication data.
10
PLL-CLK
O
Front-end communication clock.
11
L-DATA L
I
LCD driver communication data.
12
L-DATA S
O
LCD driver communication data.
13
L-CLK
O
LCD driver communication clock.
14
R-DATA
I
RDS data.
15
R-QUAL
I
RDS QUAL.
16
CH-DATA C
I
Changer communication data.
17
CH-DATA H
O
Changer communication data.
18
CH-CLK
I/O
Changer communication clock.
19
M-STBY
I
Cassette tape standby detection.
"H" : Standby
20
T-END
I
Tape end detection. "H" : Run, "L" : Stop
21
ACC-DET
I
ACC detection.
22
BU-DET
I
Backup detection.
23
IC2 TYPE 0
I
For service. "L" : Normally
24
IC2 TYPE 1
I
For service. "L" : Normally
25
TYPE 0
I
Destination discrimination.
26
TYPE 1
I
Destination discrimination.
27
TYPE REF
O
Reference voltage for destination
and service.
28
MOTOR
O
Cassette mechanism motor.
"H" : ON, "L" : OFF
29
PLL-CE
O
Front-end communication ship enable.
30
SD
I
Station detection. "H" : Station exists,
"L" : Station does not exist
31
ASF
O
Noise detection time constant switch.
32
LO/DX
O
Local seeking switch. "H" : LO, "L" : DX
33
VSS1
-
GND.
34
P-MUTE
O
Power amplifier muting.
35
SVR
O
SVR control.
36
-
-
-
37
IC2-SCL
O
E-volume communication clock.
38
IC2-SDA
I/O
E-volume communication data.
39
MUTE
O
Muting control.
40
P-STBY
O
Power amplifier standby.
Pin No.
Pin Name
I/O
Function / Operating Condition
41
P. CON-DET
I
P. CON short-circuited detection.
42
CH-CONT
O
Changer control.
43
-
-
-
44
CH-REC H
O
Changer request.
45~47
-
-
-
48
EN2-1
O
Power supply IC control.
49
EN2-0
O
Power supply IC control.
50
BEEP
O
Buzzer.
51
EN3
O
Power supply IC control.
52
EN1
O
Power supply IC control.
53
SW 5V
O
P. ON 5V control. "H" : OFF, "L" : ON
54
MUSIC
I
Tape signal detection. "H" : Signal
does not exist, "L" : Signal exists
55
MS-CONT
O
tape advanced sensitivity control.
"H" : Play, "L" : FF/REW
56
EQ-MUTE
O
Cassette tape muting. "H" : ON, "L" : OFF
57
FWD/REV
I
Cassette tape runing direction detection.
"H" : FWD, "L" : REV
58
SUB+
O
Sub motor control.
59
SUB-
O
Sub motor control.
60
RESET
I
System reset.
61
REMOTE
I
Remote control.
62
R-CLK
I
RDS clock.
63
CH-REQ C
I
Changer request.
64
PACK-IN
I
Cassette tape pack-in detection.
65
KEY-REQ
I
Key signal detection.
66
-
-
-
67
VSS0
-
GND.
68
VDD1
-
VDD.
69
X2
-
Main system clock.
70
X1
I
Main system clock.
71
IC
-
-
72
-
-
-
73
XT1
-
VDD.
74
VDD0
-
VDD.
75
AVREF 0
I
Reference voltage.
76
S-METER
I
SD detection.
"H" : SD exists, "L" : SD does not exist
77
T-MODE
I
Cassette tape mode detection.
78
PHONE
I
Navi mute : Over 2.5V,
Tel mute : Less tha 2.5V
79
NOISE
I
Noise detection during FM mode.
80
AV CONT
O
reference voltage.


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KRC-31Y/36/366L/37/Y
/391/394/Y/466R/4904Y
5
ADJUSTMENT
BALANCE/FADER/BASS/TREBLE : CENTER
T. ADV/METAL/DOLBY NR/AUTO : OFF
No.
Item
Input
Output
Receiver
Alignment
Align For
Fig.
Settings
Settings
Settings
Points
FM Section
While holding preset "1" key,
press and hold preset "6" key
98.1MHz
TEST MODE : ON
for a few seconds.
1SD
0 dev
­
FM
Preset "1" key, and
"ADJ OK" is good.
35dB
µ
98.1MHz
preset "6" key
"ADJ NG" is not good.
(ANT input)
(7 seg model :
"1111" is good.
"0000" is not good.)
AM Section
While holding preset "1" key,
press and hold preset "6" key
990kHz
TEST MODE : ON
for a few seconds.
(1)
SD
0% mod
­
AM
Preset "1" key, and
"ADJ OK" is good.
35dB
µ
990kHz
preset "6" key
"ADJ NG" is not good.
(ANT input)
(7 seg model :
"1111" is good.
"0000" is not good.)
Cassette Deck Section
TCC-153
Head azimuth screw
Adjust so that output level in
1
AZIMUTH
10kHz
SP OUT
TAPE PLAY
(FWD/REV)
playing "FWD" and "REV"
(a)
becomes maximum each.
TEST MODE : ON
While holding the "FM" key and preset "6" key, reset the unit.
TEST MODE : OFF
Reset the unit.
(a) AZIMUTH
FWD
REV
PANEL FRONT