Kenwood KR-C2902 Service Manual

2002-1 PRINTED IN JAPAN

B51-7882-00 (N)1089

CASSETTE RECEIVER

KRC-2902YA/G

SERVICE MANUAL

45Wx4

HIGH POWER

KRC-2902

LOUD

PWR OFF

AMEAUTO

CLK

SRC

AUD

T. CALL

WIDE BAND

REW

Lever (D10-3031-04)x2

Plastic cabinet assy (A02-1486-13)

Mounting hardware assy (J21-9491-13)

DC cord (E30-4790-05)

Antenna adaptor (T90-0523-05)

Escutcheon (B07-2124-02)

Knob (ATT) (K25-1388-03)

Cassette lid (A53-1638-13)

Panel assy (A64-2520-02)

KRC-2902YA/G

BLOCK DIAGRAM

IC1

KEY

PAN 5V

MUTE

B.U. DET.

B.U.

ACC

POWER IC

EQ. AMP.

CH ISO AMP

NC/MPX/

E-VOL.

FRONT Lch

FRONT Rch

REAR Lch

REAR Rch

LCD DRIVER

LCD

MAIN

TAPE MECHA.

IC5

IC2

IC4, Q151

IC3,Q150

SP OUT

PAN IN SW

ACC DET.

P-CONT.

IC1

FM+B

Q200,201

AM+B

Q202,203

AM BPF

FM BPF

Q320

Q50

Q350-353

Q53

SW 5V

Q54-57

COM+B

Q58-61

ILLUMI.

B.U. 5V

Q51,52

SYSTEM u-COM

RST SW

Q301

MOTOR SW

RST

Q260,261

ED1 Q1

FM ANT AM ANT RF GND

FM+B

AM+B

OSC GND OSC GND OSC GND

PLL +B

IFC OUT

SDA SCL

DIG GND

IF1+B

IF1 GND

S-METER

IF2 GND

FM+B

SW5V

ACC DET

B.U. DET

SCL

MUTE

SDA

P CON

PANEL

HOLD

L CLK

L DATA S

L DATA L

FWD/REV

MOTOR

Rch

COM

Lch

MP IN

MPX

OUT RR

OUT LR

OUT RF

LEVEL

SCL

SDA

OUT LF

STBY

MUTE

Rch

Lch

T-MUTE

FWD

REV

B.U.5V

B.U.

S MUTE

B.U.5V

AM+B

VDD 5V

PACK IN

L RES

ANT CON

BEEP

SVR

AMP. STBY

SVR

AC GND (BEEP)

Rch

Lch

RF GND

OSC GND

IF2 +B

AUDIO OUT

S-METER

PLL CLK

PLL DATA

PLAY HEAD

55.6mV

B.U.5V

SW5V

B.U.5V

AM: 170mV

FM: 400mV

TAPE

PACK IN

(FF/REW)

AMP. MUTE

FF/REW

B.U.5V

ILLUMI.

(X16- )

(X14- )

D200

P-CONT. /ANT-CONT.

KRC-2902YA/G

● SYNTHESIZER UNIT (X14-6872-73)

COMPONENTS DESCRIPTION

Ref.No. Function Operation

IC1 SYSTEM µ-COM Controls the unit. IC2 E -VOLUME Controls the volume and selects source. IC3 M UTE LOGIC Controls the mute output. IC4 POWER AMPLIFIER For the speaker output. IC5 EQUALIZER AMPLIFIER For the cassette tape's signal.

IC6 RESET Resets the power. Q49 A CC DETECTION SW Outputs "H" during the ACC off. Q50 BACK-UP DETECTION SW Outputs "H" when the back-up voltage is under 9.2V.

Q51,52 BACK-UP 5V DRIVER Works when back-up current exists.

Q53 P.ON 5V SW Works during the power on.

Q54,55 8V SW Works during the power on. Q56,57 8V DRIVER Works during the power on. Q58,59 ILLUMI +B SW Works during the power on. Q60,61 ILLUMI +B DRIVER Works during the power on.

Q150 E-VOL MUTE SW

Works when the back-up current is detected or the changer mute works or system

-com mute works.

Q151

SVR FORCED DISCHARGE SW

Works when the amplifier mute works. Q201 FM +B SW Works during FM mode. Q203 AM +B SW Works during AM mode. Q260 MOTOR +B SW Works during the tape mode. Q261 MOTOR +B DRIVER Works when Q206 works. Q301 CD-CH RESET SW Works when the power is reset and the reset SW works. Q320 PANEL 5V SW Works when the back-up current exists and the panel is attached on the unit. Q350 P.CON DRIVER SW Does not work during the power off and the ALL OFF. Q351 P.CON PROTECTION SW Works when the P.CON is short-circuited on the GND. Q352

P.CON PROTECTION INHIBIT SW

Inhibits the protection SW in a moment during the P.CON on. Q353 P.CON DRIVER SW Does not work during the power off and the ALL OFF.

KRC-2902YA/G

● µ-COM (IC1 : X14-)

Pin No.

Pin name I/O Description

Processing Operation

1 PANEL I Panel detection. "L" : Panel exists. 2 L CE O LCD driver chip enable. 3 L RES O LCD driver reset. 4 AVSS - GND. 5 R DATA I RDS data. 6 R QUAL I RDS receiving. 7 AVREF 1 - Reference voltage. 8 I C2 SEL 1 I Selector. "L" : Normally.

9 I C2 SEL 0 I Selector. "L" : Normally. 10 - - - 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. -

14,15 - - - -

16 DATA C I Changer communication data. 17 DATA H O Changer communication data. 18 CH CLK I Changer communication clock. -

19-26 - - - -

27 MOTOR O Cassette tape motor SW. 28 FF/REW I Cassette tape FF/REW detection. "L" : FF or REW works.

29-31 - - - -

32 SD I Signal detection. "H":Signal exists. "L" : Signal does not exist. 33 VSS 1 - GND. 34 - - - 35 PLL CLK O Front-end communication clock. 36 PLL DATA I/O Front-end communication data. 37 AM +A O AM power supply SW. 38 FM +B O FM power supply SW. 39 IC2 DATA I/O E-volume communication data. 40 IC2 CLK O E-volume communication clock. 41 AFC O FM noise detection /Time constant SW. 42 MUTE O Mute control. 43 AMP MUTE O Power amplifier mute. 44 - - - 45 CH CNT O Changer control. 46 REQ H O Changer request. 47 - - - 48 SVR O SVR control. -

MICROCOMPUTER'S TERMINAL DESCRIPTION

KRC-2902YA/G

Pin No.

Pin name I/O Description

Processing Operation

49 AMP STBY O Power amplifier stand-by. 50 BEEP O Buzzer signal output. -

51,52 - - - -

53 P.CONT O Power control SW. 54 ACC DET I ACC detection. 55 B.U.DET I Back-up detection. 56 P.ON O Power SW. 57 ILLUMI O Illumination SW. 58 FWD/REV I Cassette mechanism FWD/REV detection. 59 - - - 60 RESET I System reset signal input. 61 SEL 1 I Destination SW. 62 R CLK I RDS clock. 63 REQ C I Changer request. 64 PACK IN I Cassette tape pack-in detection. 65 KEY-REQ I Key signal input detection. 66 SEL 0 I Destination SW. 67 VSS 0 - GND. 68 VDD 1 - 5V power supply. 69 X2 - Main system clock. 70 X1 I Main system clock. 71 IC - GND. 72 - - - 73 XT1 - 5V power supply. 74 VDD 0 - 5V power supply. 75 AVREF 0 I A/D converter reference voltage. 76 S METER I S-meter detection. "H" : S-meter exists. "L" : S-meter does not exist.

77 PHONE I -

Navigation mute : 2.5V or more.

Telephone mute : 1V or less. 78 NOISE I FM noise detection. 79 AV CONT O A/D converter reference voltage. 80 - - - -

MICROCOMPUTER'S TERMINAL DESCRIPTION

KRC-2902YA/G

TEST MODE / ADJUSTMENT

(2-LINE TAPE)

(FWD)

(RVS)

HEIGHT

(FWD)

HEIGHT/AZIMUTH

(FWD)

HEIGHT/AZIMUTH

(RVS)

TAPE SPEED

HEIGHT

(RVS)

1. How to enter the test mode

• Reset the unit while holding the "FM" key and preset "6" key.

• All indication segments go ON at the beginning of the test mode.

2. How to release the test mode

• Simply reset the unit.

• (NOTE) The test mode is not canceled by ACC OFF, power OFF, momentary power down or the panel off.

3. Audio adjustment

• Set the volume level to -10dB (which is shown as "30" on the display).

• Loudness OFF.

• The BASS/TREBLE and BALANCE/FADER can be set to the full-boost/full-cut and full-front/full-rear each by pressing the "Track UP" / "Track DOWN" keys.

• Sound coordination doesn't appear for the feed.

TEST MODE

ADJUSTMENT

Head Angle Adjustment

Head height alignment procedure

• During FWD transport adjust screws F and F' so that line A of 2-LINE TAPE passes trough the center of the head shield plate (core center area)

• During RVS transport adjust screws R and R' so that line B of 2-LINE TAPE passes trough the center of the head shield plate core (center area)

• 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)

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