Kenwood KRC-33R, KRC-378R, KRC-480R Service Manual

CASSETTE RECEIVER

KRC-33R

SERVICE MANUAL

KRC-378R/RY

MECHANISM EXTENSION CORD

W05-0477-00 (7P) W05-0609-00 (10P)

KRC-480R

SRC

PWR OFF

LOUD

SRC

PWR OFF

LOUD

EJECT

/ PTY

VOL ADJ

CLK NAME.S

SCAN B.S/RDM REP

D.SCN

M.RDM

KRC-378R

40W 4

CD MD-CHANGER CONTROL

DISC

EJECT

/ PTY

VOL ADJ

CLK NAME.S

SCAN B.S/RDM REP

D.SCN

M.RDM

KRC-33R

40W 4

CD MD-CHANGER CONTROL

DISC

SRC

PWR OFF

LOUD

EJECT

/ PTY

VOL ADJ

CLK NAME.S

SCAN B.S/RDM REP

D.SCN

M.RDM

KRC-480R

40W 4

CD MD-CHANGER CONTROL

DISC

KRC-480R (M)

KRC-33R (E)

KRC-378R/RY (E)

DC CORD (E30-4792-05)

PLASTIC CABINET ASSY (A02-1486-13)

LEVER (D10-xxxx-xx) x2

MOUNTING HARDWARE ASSY (J21-9491-03)

(Refer to the parts list.)

ANTENNA ADAPTOR (T90-0523-05) (Except KRC-480R)

REMOTE CONTROLLER ASSY (A70-0883-05) (KRC-480R only)

STAY (J54-0606-04) (KRC-480R only)

SCREW SET (N99-1632-05) (KRC-480R only)

SCREW SET (N99-1610-15) (KRC-480R only)

BATTERY (Non-service part) (KRC-480R only)

40%

IC8

RDS DECODER

IC1

KEY

PANEL 5V

MUTE

B.U DET.

B.U

ACC

P-CONT.

MUTE

PRE OUT

POWER IC

MOTOR DRIVER

IC6

EQ. AMP

CH. ISO AMP.

N.C/MPX

E-VOL.

CD/MD CHANGER

FRONT Lch

FRONT Rch

REAR Lch

REAR Rch

LCD DRIVER

LCD

ME1

MAINSUB

IC5

1 Lch

2 Rch

PRE OUT

IC2

IC4

IC10

SP OUT

REAR

SUB

DSI

REMOTE

RESET SW

PANEL SW (GND)

GRN/RED

u-COM RESET

IC9

ACC DET.

P-CONT.

TEL MUTE

DRIVER

Lch

Rch

PRE OUT

FRONT

CN3

IC1

(40W)

FRONT-END UNIT

FM+B

Q61,63

AM+B

Q62,64

R216

AM BPF

FM BPF

R205,C207,211

R206,C206,212

MP SW

IC2

Q65

Q20

u-COM RESET

D18,19

Q21

Q2,3

D1-17

Q57-60

Q18

Q19

Q14-17

SW5V

Q4,5

SW14W

Q6,7

8V AVR

Q10-13

ILLUMI. AVR

AVR

B.U.5V

Q1,2

u-COM

ED1

DRIVER

FM ANT

AM ANT

OSC 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

SUB+ SUB-

PON

ACC DET

B.U DET

SCL

MUTE

SDA

P CON

PANEL

RESET

L-RESET

L-CLK

L-DATA S

L-DATA L

DSI

FWD/REV

T-MODE

MOTOR

CH CON

DATA H

DATA C

REQ H

REQ C

CH CLK

Rch

COM

Lch

TAPE

MP IN

MPX

OUT RR

OUT LR

OUT RF

Rch

LEVEL

SCL

SDA

OUT LF

Rch

STBY

MUTE

Rch

Lch

PACK

T-END

SYBY

MODE

FWD

REV

B.U.5V

B.U

CHRST

SMUTE

B.U.5V

AM+B

VDD 5V

R QUAL

R CLK

R DATA

PACK IN

T-END

L-CE

B.U.5V

REMOTE

SW5V

GRN

RED

PHONE

CHMUTE

BEEP

SVR

STBY

SVR

AC GND(BEEP)

Lch Lch

Rch

Lch

1200mV

3 2 1

TAPE :1778mV CD/MD-CH :3592mV

AM :792mV

FM :1276mV

SW 5V

MUSIC

RF GND

OSC GND

IF2 +B

AUDIO OUT

S-METER

PLL-SCL

PLL-SDA

M2 M1

Ref.103

Ref.94

Ref.95

Ref.105

Ref.102

HD1

AFC

NOISE

QUAL

MPOUT

MUTE

EQ MUTE

340mV

M-STBY

B.U.5V

SW5V

B.U.5V

AM: 175mV

FM: 213mV

(X13)

KRC-33R,378R/RY,480R (E,E/E,M)

KRC-33R,378R/RY,480R

BLOCK DIAGRAM

KRC-33R,378R/RY,480R

SYNTHESIZER UNIT (X14-6xxx-xx)

REF.

No.

FUNCTION OPERATION

IC1

-COM Controls system. IC2 ELECTRIC VOLUME Switches each source, decodes FM stereo signal, controls sound. IC4 POWER IC Amplifies power so that the speaker can drive audio signal. IC5 EQUALIZER AMPLIFIER Amplifies and equalizes the cassette head output signal (120

sec). IC6 SUB MOTOR CONTROLLER Controls sub motor's loading and eject modes. IC8 RDS DECODER Decodes RDS signal from tuner MPX signal.

IC9

-COM RESET

Resets

-COM after detecting the back-up voltage comes

less than 3V.

IC10 MUTE DRIVER

Mutes power IC (IC4) and E-volume (IC2) when the back-up is detected and

-COM mute signal is output.

Q1,2 BACK-UP 5V AVR Usually output 5V when battery is connected.

Q3 SW 5V Outputs 5V when

-COM makes Q3's base level "L".

Q4,5 SW 14V

Q4's corrector outputs the back-up 14V when

-COM makes Q5's

base level "H".

Q6,7 8V AVR Output 8V. Q8,9 MAIN MOTOR SW Output 14V when

-COM makes Q9's base level "H".

Q10-13 ILLUMINATION AVR

Q12's corrector outputs 10.3V when

-COM makes Q11's

base level "H".

Q14 P-CON. START-UP

Cancels Q15's protection circuit effected by C9 time constant and Q14's inner base resister.

Q15 P-CON. PROTECTION CIRCUIT

Stops output signal, and makes Q16's base level "H" when P-CON output comes GND shorted.

Q16,17 P-CON. SW Outputs the back-up 14V when Q17's base level comes "H".

Q18 ACC DETECTION

Corrector level comes "L" when ACC comes "ON". Detection voltage : 8.95V.

Q19 BACK-UP DETECTION

Corrector level comes "L" when the back-up comes "ON". Detection voltage : 9.0V.

Q20

-COM RESET Resets -COM when Q20's base level comes "H". Q21 DSI Indicates when Q21's base level comes "H". Q51 POWER AMPLIFIER SVR CONTROLLER SVR level comes "L" when

-COM makes Q51's base level "H". Q52 PREOUT MUTE CONTROLLER Mutes preout sound when Q52's base level comes "L". Q53 ELECTRIC VOLUME MUTE Mutes E-volume (IC2) signal when Q53's base level comes "H".

Q54,55 AFC Switches AFC time constant.

Q56 MPX BUFFER For the front-end MPX output buffer (Emitter follower).

Q57-60 PREOUT MUTE CONTROLLER Mutes preout sound when Q52's base level comes "L".

Q61 FM+B SW "ON" when Q61's base level comes "H". Q62 AM+B SW "ON" when Q62's base level comes "H". Q63 FM+B SW "ON" when Q61's base level comes "H". Q64 AM+B SW "ON" when Q62's base level comes "H". Q65 PANEL SW "ON" when Q65's base level comes "L" (Panel OFF). Q67 NOISE BUFFER For E-volume (IC2) output buffer (Emitter follower).

COMPONENT DESCRIPTION

KRC-33R,378R/RY,480R

(X14-) IC1 : -COM

PORT

No.

PORT NAME I/O FUNCTION

OPERATING CONDITION

1 AV CONT O Analogue reference voltage control. Active "H". 2 IC2 TYPE O I Stereo signal data switch.

IC2 TYPE 1 I Stereo signal data switch.

4 AVSS - Analogue GND.

MOTOR O Cassette mechanism power supply control.

"H" : Mechanism motor +B "ON". "L" : Mechanism motor +B "OFF".

6 M-STBY I

Stand-by signal input from the cassette mechanism.

"H" when the stand-by signal exists. "L" when the other signal exists.

AV REF 1 - 5V power supply for D/A converter reference voltage.

8 ILLUMI O Illumination power supply control.

"H" : Illumi. "ON" or the ALL OFF mode. "L" : Illumi. "OFF".

L-RESET

O Reset signal output to LCD driver (X13-).

"L" : Reset.

10 PANEL I Panel detection signal input.

"H" : Panel OFF. "L" : Panel ON.

L-DATA L I Data input from LCD driver.

12 L-DATA S O Data output from LCD driver.

L-CLK O Data clock output from LCD driver.

14,15 N.C. - -

CH-DATA C I Data input from the changer.

17 CH-DATA H O Data output to the changer.

CH-CLK I/O Changer communication clock input and output.

19 L-CE O LCD driver data control.

Active "H".

SUB+ O Sub motor control signal output.

21 SUB- O Sub motor control signal output.

MS-CONT O No audio signal detection level switch to equalizer amplifier.

"H" : PLAY. "L" : FF/REW.

23 EQ-MUTE O Mute control signal output to equalizer amplifier.

"H" : FF/REW or the other source. "L" : TAPE PLAY.

PLL-SCL O Communication clock signal output to the front-end.

25 AM+B O Front-end's AM power supply control output.

"H" : AM+B "ON".

FM+B O Front-end's FM power supply control output.

"H" : FM+B "ON".

27 N.C. - -

DSI O DSI's LED on/off switch.

"H" : LED "ON".

MUSIC

I No audio signal detection level input to equalizer amplifier.

"H" when audio signal does not exist. "L" when audio signal exists.

FWD/REV

I Tape FWD/REW signal input.

"H" : Forward. "L" : Reverse.

31 R-DATA I Data input from RDS decoder.

R-QUAL I Qual input from RDS decoder.

33 VSS1 - GND.

SD I SD signal input from the front-end.

"H" when the carrier signal exists. "L" when the carrier signal does not exist.

35 IC2-SCL O Clock output to E-volume (IC2).

N.C. - -

37 PLL-SDA I/O Data input and output to the front-end.

IC2-SDA I/O Data input and output to E-volume (IC2).

39 MUTE O Preout and mute signal output to E-volume (IC2).

"H" : Mute "ON". "L" : Mute "OFF".

N.C. - -

CIRCUIT DESCRIPTION

(X14-) IC1 : -COM

PORT

No.

PORT NAME I/O FUNCTION

OPERATING CONDITION

AFC

O Noise detection time constant switch.

"L" : FM seeking. "H" : The other condition.

42-44

N.C. - -

P-MUTE

O Mute signal output to the power IC (IC4).

"L" : Power IC (IC4) mute.

SVR

O SVR signal output to the power IC (IC4).

"L" when P.ON goes down.

47 STBY O Stand-by signal output to the power IC (IC4).

"H" : Power IC (IC4) "ON". "L" : Power IC (IC4) "OFF".

P-CON O Control signal output to P-CON or P-ANT.

"H" : P-CON signal output "ON". "L" : P-CON signal output "OFF".

49 N.C. - -

BEEP O Buzzer signal output.

Beep sound output.

ACC-DET

I ACC detection signal input.

"H" : ACC "OFF". "L" : ACC "ON".

BU-DET O Back-up voltage detection signal input.

"H" when back-up signal does not exist. "L" when back-up signal exists.

CH-REQ H

O Request signal output to the changer.

"L" : Request.

CH-CON O Changer control.

"H" : Changer mode. "L" : The other mode.

55 N.C. - -

SW5

O SW 5V power control signal output.

"L" : SW 5V "ON".

P.ON O P.ON power supply control signal output.

"H" : Power "ON". "L" : Power "OFF".

58,59

---

RESET

I System reset signal input.

"L" : Reset. "H" : The other condition.

REMOTE I Data input from the remote controller.

R-CLK I Data clock input from RDS decoder .

CH-REQ C I Request input signal from the changer.

PACK IN I Insertion detection signal input from cassette mechanism.

"H" : Pack in. "L" : Pack out.

KEY-REQ

I Key request.

Active "L".

T-END I Tape-end detection signal input from cassette mechanis.

"H" : Tape running. "L" : Tape-end.

VSS 0 - GND.

VDD 1 - Power supply.

X2 - For main system clock oscillation.

X1 I For main system clock oscillation.

IC/TEST - For flash memory writing.

XT2 - -

VDD 0 - Power supply.

AV REF 0 I 5V power supply (For A/D converter reference voltage).

S-METER I S-meter voltage input from the front-end.

"H" : SD signal exists. "L" : SD signal does not exist. Vth : Fit the new front-end.

T-MODE I Tape mode input from cassette mechanism.

Vth : 2.5V.

PHONE I Phone (Tel-mute) voltage input.

Tel mute : More than 1V. Navi mute : Less than 2.5V.

NOISE I Voltage input from E-volume (IC2)’s noise amplifier.

TYPE 0 I Destination switching.

"H" : KRC-478RV/RYV. "L" : The other models.

KRC-33R,378R/RY,480R

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 check the test mode

• Cancel the blank skip (B.S).

• Push the “ATT” key.

• The eject function works.

3. 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.

4. Audio adjustment

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

• Loudness OFF.

• The BAS S /TREBLE and BALANCE/FADER can be set to the full-boost/ful l-cut a nd full-front/full-rear each by pressing the “Track UP” / “Track DOWN” keys.

• Sound coordination doesn't

appear

for the feed.

TEST MODE

BALANCE/FADER/BASS/TREBLE : CENTER T.ADV/METAL/DOLBY NR/AUTO : OFF

No. ITEM

INPUT

SETTINGS

OUTPUT

SETTINGS

RECEIVER

SETTINGS

ALIGNMENT

POINTS

ALIGN FOR FIG.

CASSETTE DECK SECTION

1 AZIMUTH

TCC-153

10KHz

(B) TAPE PLAY

Head azimuth

screw

(FWD/REV)

(ME1)

Adjust so that output

level in playing "FWD"

and "REV" becomes

maximum each.

(b)

(b) AZIMUTH

PANEL FRONT

FWD

REV

FM-SG

MPX-SG

AC Voltmeter Oscilloscope

FM-SG

AM-SG

(A)

(B)

(C)

(D)

(REAR VIEW)

KRC-33R,378R/RY,480R

ADJUSTMENT

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