Kenwood KRC-4904Y, KRC-466R, KRC-394Y, KRC-394, KRC-391 Service Manual

CASSETTE RECEIVER

KRC-31Y/36/366L/37/37Y /391/394/394Y/466R /4904Y

SERVICE MANUAL

© 2002-10 PRINTED IN JAPAN B51-7986-00 (N) 2139

Mechanism extension cord : W05-0477-00 (7P), W05-0609-00 (10P)

KRC-36/37/37Y

/391/394

/394Y/466R

KRC-XXXX

							45Wx4
							DISC
LOUD	SCRL	SCAN	B.S/RDM	REP	T.CALL	M.RDM	CLK MENU TI VOL ADJ
SRC							AUD
OFF

KRC-31Y/366L

KRC-XXXX

							45Wx4
							DISC
LOUD	SCRL	SCAN	B.S/RDM	REP	T.CALL	M.RDM	CLK MENU AUTO AME
SRC							AUD
OFF

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)

KRC-4904Y

							WIDE BAND
		KRC-4904
							45Wx4
							DISC
LOUD	SCRL	SCAN	B.S/RDM	REP	T.CALL	M.RDM	CLK MENU AUTO AME
SRC							AUD
OFF

Panel assy (A64-2948-02)

DC cord	Plastic cabinet assy	Mounting hardware assy	Escutcheon
(E30-4792-05)	(A02-1486-13)	(J21-9716-03)	(B07-)

Screw set	Screw set	Antenna adaptor	Lever
(N99-1610-15)	(N99-1719-05)	(T90-0523-05)	(D10-4589-04) x2

Depends on model. Refer to the parts list.

2

(X14)
TUNER	ANT.
RF GND
FM ANT
AM ANT
FM+B	FM+B
AM+B	AM+B
AM LO/DX
FM LO/DX
IF SELECT
RDS OUT

SW5V

IC6

RDS DECODER

REQUEST
K2I-VTH
VCO-GND
FM SD OUT
FSD OUT
FM DET OUT
AM DET OUT
COMMON+B	A8V
IF GND
HI UP ADJ
PLL CE
PLL DATA
PLL CLK
P-ON 5V	SW5V
DIG GND

IC10

SUB MOTOR DRIVER

	AUDIO	AVR
	8V
	MOTOR	BU14V
	DRIVER

SW5V

	M	M
	SUB	MAIN
	T-MODE
	T-END	PACK
		IN
	M-STBY	FWD
		REV
	Lch
	PLAY HEAD
	Rch

FM : 213mV

AM : 160mV

IC1

CLKCH

CREQ

HREQ

CATAD

HATAD

CONCH

RSTCH

R DATA

R CLK

R QUAL

LO/DX

AFS

SD

S-METER

SYSTEM u-COM

PLL-CE

PLL-DATA

PLL-CLK

SUB+

SUB-

MOTOR

END-T

STBY-M

MODE-T

INCKAP

FWD/REV

DSI

MUSIC

MUTE-EQ

CONT-MS

REMO

CE-L

LATAD-L

DSI

IC9

BU5V

TAPE L/R

Lch

COM

MUSIC

Rch

EQ-MUTE

MS-CONT

EQ AMP

MUTECH	NOISE	SDA
		SCL

				BEEP
				SVR
				P-STBY
				P-MUTE
				MUTE
				BU-DET
				ACC-DET
				PHONE
				EN1
				EN2
				EN3
				SW5V
SATAD-L	CLK-L	RES-L	RESET	ANELP

	IC11
BU5V	RST IC

AUDIO 8V	SW5V	PAN 5V

(X16)		PAN IN SW
REMO
IC2		Q2,3
	5	RED or
IC1		GREEN
LCD DRIVER		RED
	GREEN
10
LCD	KEY

			IC2
			MPX
			AM
			LEVEL
			MP IN
			AFS
			QUAL
				CD ISO AMP
				E-VOL
			SDA
			SCL
		IC12
	ASD	SCL	SMUTE	L/RAPET
	E2PROM
	SW5V

1200mV
CD L/R
OUT LF
AUDIO 8V
OUT RF
OUT LR
OUT RR
FM	: 1345mV
AM	: 850mV
TAPE	: 1786mV
CD-CH : 3546mV

SVR

IC8

MUTE

DRIVER

AMP

MUTE

SW5V

THERMO PROTECTION

8

BU14V

IC4

POWER IC

TDA7386

AC GND(BEEP) SVR STBY MUTE

J4

CD/MD

CHANGER

CD L/R

SP OUT

FRONT Lch

FRONT Rch

REAR Lch

REAR Rch

J5

PRE OUT

		R-Lch
	PRE
	MUTE
		R-Rch
	FM	: 1727mV
BU5V	AM	: 550mV
	TAPE	: 1719mV
	CD-CH : 3424mV
340mV
		BU14V
	SURGE-DET	J2
		DC CONNECTOR
	B.U. DET	B.U.

RST SW	IC7
BU14V
FM+B	FM+B
AM+B	AM+B
AUDIO 8V	AUDIO
	ILLUM
BU5V	B.U.5V

	BU5V
SW5V	SW5
	ACC DET	ACC
VOLTAGE	EN1
REGULATOR	EN2
	EN3
	TEL DET	TEL MUTE
	P,CON	P-CONT

/391/394/Y/466R/4904Y

31Y/36/366L/37/Y-KRC

DIAGRAM BLOCK

TAPE MECHA

KRC-31Y/36/366L/37/Y /391/394/Y/466R/4904Y

COMPONENTS DESCRIPTION

● SYNTHESIZER UNIT (X14-689x-xx)

Ref. No.	Function	Operation
IC1	System -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”.

● 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”.

3

KRC-31Y/36/366L/37/Y /391/394/Y/466R/4904Y

MICROCOMPUTER’S TERMINAL DESCRIPTION

● Microcomputer : UPD780058GCxxx (X14 : IC1)

Pin No.

Pin Name

I/O

Function / Operating Condition

Pin No.

Pin Name

I/O

Function / Operating Condition

1

DSI

O

DSI control.

41

P. CON-DET

I

P. CON short-circuited detection.

2

PANEL

I

Panel detection. “L” : Panel exists

42

CH-CONT

O

Changer control.

3

-

-

-

43

-

-

-

4

AVSS

-

GND.

44

CH-REC H

O

Changer request.

5

L-RST

O

LCD driver reset.

45~47

-

-

-

6

L-CE

O

LCD driver chip enable.

48

EN2-1

O

Power supply IC control.

7

AVREF1

I

Reference voltage.

49

EN2-0

O

Power supply IC control.

8

-

-

-

50

BEEP

O

Buzzer.

9

PLL-DATA

I/O

Front-end communication data.

51

EN3

O

Power supply IC control.

10

PLL-CLK

O

Front-end communication clock.

52

EN1

O

Power supply IC control.

11

L-DATA L

I

LCD driver communication data.

53

SW 5V

O

P. ON 5V control. “H” : OFF, “L” : ON

12

L-DATA S

O

LCD driver communication data.

Tape signal detection. “H” : Signal

54

MUSIC

I

13

L-CLK

O

LCD driver communication clock.

does not exist, “L” : Signal exists

14

R-DATA

I

RDS data.

55

MS-CONT

O

tape advanced sensitivity control.

15

R-QUAL

I

RDS QUAL.

“H” : Play, “L” : FF/REW

16

CH-DATA C

I

Changer communication data.

56

EQ-MUTE

O

Cassette tape muting. “H” : ON, “L” : OFF

17

CH-DATA H

O

Changer communication data.

Cassette tape runing direction detection.

57

FWD/REV

I

18

CH-CLK

I/O

Changer communication clock.

“H” : FWD, “L” : REV

19

M-STBY

I

Cassette tape standby detection.

58

SUB+

O

Sub motor control.

“H” : Standby

59

SUB-

O

Sub motor control.

20

T-END

I

Tape end detection. “H” : Run, “L” : Stop

60

RESET

I

System reset.

21

ACC-DET

I

ACC detection.

61

REMOTE

I

Remote control.

22

BU-DET

I

Backup detection.

62

R-CLK

I

RDS clock.

23

IC2 TYPE 0

I

For service. “L” : Normally

63

CH-REQ C

I

Changer request.

24

IC2 TYPE 1

I

For service. “L” : Normally

64

PACK-IN

I

Cassette tape pack-in detection.

25

TYPE 0

I

Destination discrimination.

65

KEY-REQ

I

Key signal detection.

26

TYPE 1

I

Destination discrimination.

66

-

-

-

27

TYPE REF

O

Reference voltage for destination

67

VSS0

-

GND.

and service.

68

VDD1

-

VDD.

28

MOTOR

O

Cassette mechanism motor.

69

X2

-

Main system clock.

“H” : ON, “L” : OFF

70

X1

I

Main system clock.

29

PLL-CE

O

Front-end communication ship enable.

71

IC

-

-

30

SD

I

Station detection. “H” : Station exists,

72

-

-

-

“L” : Station does not exist

73

XT1

-

VDD.

31

ASF

O

Noise detection time constant switch.

74

VDD0

-

VDD.

32

LO/DX

O

Local seeking switch. “H” : LO, “L” : DX

75

AVREF 0

I

Reference voltage.

33

VSS1

-

GND.

76

S-METER

I

SD detection.

34

P-MUTE

O

Power amplifier muting.

“H” : SD exists, “L” : SD does not exist

35

SVR

O

SVR control.

77

T-MODE

I

Cassette tape mode detection.

36

-

-

-

78

PHONE

I

Navi mute : Over 2.5V,

37

IC2-SCL

O

E-volume communication clock.

Tel mute : Less tha 2.5V

38

IC2-SDA

I/O

E-volume communication data.

79

NOISE

I

Noise detection during FM mode.

39

MUTE

O

Muting control.

80

AV CONT

O

reference voltage.

40

P-STBY

O

Power amplifier standby.

4

KRC-31Y/36/366L/37/Y /391/394/Y/466R/4904Y

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.
			0 dev			Preset “1” key, and	“ADJ OK” is good.
	1	SD		–	FM
			35dB			preset “6” key	“ADJ NG” is not good.
					98.1MHz
			(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.
			0% mod			Preset “1” key, and	“ADJ OK” is good.
	(1)	SD		–	AM
			35dB			preset “6” key	“ADJ NG” is not good.
					990kHz
			(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		SP OUT	TAPE PLAY		playing “FWD” and “REV”	(a)
			10kHz			(FWD/REV)
							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

5

A

B

C

D

E

1	PC BOARD (COMPONENT SIDE VIEW)

2

3

4

5

6

X14-689x-xx (J74-1321-02)

W17

01

1

C531

J5

IC7

CN1

R231

C514

R232

2

12

C513

R229

J6

R230

1

C52

13

C56

C509

C517

C55

C50

C402

C403

C54

2 1

C51

C518

C53

8 4 3

7 5

R402

R407

R405

R404

D404

D401

C222

C221

W25

R501

C501

D101

R537

R403

R401

C401

C505

111312

1096

C223

W24

RES

5V

J4

R408

R411

R410R406

R409

D409DTC

D410DTH

CLKD411

D403

D402

D407

R221

R224

R223

W23

W21

C101

C224

C507

R222

GND

TEST

L101

W22

C251

D40

X1

R143

C253

C252

W19

25

C258

D251

W20

C203

24

C254

IC4

C257

C201

R10

D252

W18

C256

D253

D10

2

R102

1

W16

L201

W15

R103

C255

W14

D2

W3

W13

W12

W4

W11

W10

W8

W9

D3

R31

W7

R552

W6

18

J2

D4

R551

R162

R21

Q551

E

B

R20

R30

D30

R14

D11

D20

R354

D159

D160

R1

R2

W1

W5

7

D551

1

R160

2

1

W2

D157

R303

R304

D1

WH1

R305

L305

L306

C351

X2

J3

L304

CN2

C1

C353

R159

L303

R158

R157

L301

C304

R156

14

15

C1

C306

R155

L1

C301

R154

D154

R161

D161

R153

1

24

D153

1

P1

A1

Refer to the schematic diagram for the values of resistors and capacitors.	X14-689x-xx
	IC	Q	Address
	4		4A
	7		1C
		551	5D

7

6

F

G

H

I

J

PC BOARD (FOIL SIDE VIEW)

1

R536

R535

R531

C511

C512

R533

R511

R512

R534

C532

C533

C534

R519

R515 C515

R517

R513

R514

15

IC10

106

E

B

Q501

R521

1011

20

21

3031

C516

1

40

IC9

R518

C506

R516

R504

R520

C502

R502

R104

R101

R137

C508

R522

R414

C106

C103

CP101

EB

R51

3

2

R503

4

1

R129

R138C104

IC11

D102

R142R140

R141

C102

61

60

R135

CP102

R132

R145

CP103

8

7

C404

R136

Q50

C105

R50

R415

R146

R258

R123

801

IC1

41

R122

14

IC8

EB

Q101

R120

1

R144

40

4 CP10

C40

20

R118

R117

R12

R116

BE

21

R259

R11

Q10

R114

R556

R105

R106

R113

R115

R108

R554

C14

R112

R111

R413

R110

R109

R107

1

IC12

8

R412

R23

4

5

Q20

R4

BE

BE

Q552

C355

CP315

R353

9

C354

8

		1
C205
C204
R203 C209	C208	14
	C207
	C206
	C211
	C210
	R202
	R201

C20

R22

R32

28

IC2
	15	C202
	R204
	R205
BE
Q201
	R16
C30	EB	Q11

C356	IC6
E B	1			D301
16			C308
Q151
		C352	BE	C303
				C302
	C305		Q301
	C307

		R227
Q40	BE	EB	Q223
	Q224	B
		E	R225
	R228
	Q221	E	R226
		B B
	Q222
		E

		R260
		R262
R257		R261
R256
	E	Q251
	B
R263		R255
Q1		EB	C2
		R3
R15

TH1

R251

R252

C225

2

689x-X14 xx-

1321-(J74 02)-

3

C260

R253

R254

C259

4

5

6

X14-689x-xx

IC

Q

Address

IC

Q

Address

IC

Q

Address

IC

Q

Address

IC

Q

Address

1

3F

10

2F

11

5H

151

6F

301

6H

2

4H

11

3F

20

4G

201

4H

501

2F

6

5G

12

4G

40

2H

223

2I

552

5G

Refer to the schematic dia-

8

3G

1

4H

50

3G

224

2H

gram for the values of resis-

9

2G

10

4G

101

3F

251

4I

tors and capacitors.

7

7

K

L

M

N

O

1

2

3

4

5

6

7

PC BOARD (KRC-36/37/Y/391/394/Y/466R)

(COMPONENT SIDE VIEW)	(FOIL SIDE VIEW)
X16-1532-7x (J74-1303-02)	X16-1532-7x (J74-1303-02)

	D13	SRC		VOL
				D2
		KS2	KI1
				IC2
			2	1
			3	4
D3	ATT
		KS3	1	D21
	1

D4

2

ED1

D5

3

D6

4

D7

5

D8

KI4

6

D9

RST
			56
CLK
D22
D10	KS5	AM
			D20
	TI
	KS4		D12
	KS3		D11
			FM
	KI2	KI5
D14	AUD

8

D1

X16-1532-7x

(J74-1303-02)

IC Address

2 2L

X16-1532-7x

(J74-1303-02)

IC Q Address

1

4O

13O

23O

33O

Refer to the schematic diagram for the

values of resistors and capacitors.

C5

R20

R13

SW5V R10

KS4

KS5

						R14
								C6
			C8
R22
R19			DATAL	CE-L	PAN5V
REMO	LGND						14	15
D17					R9	R8	J1
L-CLK			R7		R6	DATAS
WL+B LRES D18			R5			DGND	2	1
KI1	R11	E B			R15			KI3
					Q2
	R12
		EB			Q3
			D19					Q1
						R4	E	B
			R3				C4
			R2
			R1				C3
			C1				C2
			80					65
	1							64
						IC1
	24							41
		25						40
								KI4
					R16
				RES
							KI2
								R23
	R18
						KS3
			KI5		KS2		C7
					R17