Kenwood KRC-609, KRC-679R, KRC-781R Service Manual

AUD

SCANB NR B.S/RDM REP MTL/M.RDM

PROG

LOUD

AUTO

DISP NAME.S

AME

PWR OFF

CR2

47W x 4

AUD

SCANB NR B.S/RDM REP MTL/M.RDM

PROG/PTY

LOUD

T I DISP

NAME.S

VOL ADJ

PWR OFF

47W x 4

CR2 K3I

AUD

SCANB NR B.S/RDM REP MTL/M.RDM

PROG/PTY

LOUD

T I DISP

NAME.S

VOL ADJ

PWR OFF

47W x 4

CR2 K3I

AUD

SCANB NR B.S/RDM REP MTL/M.RDM

PROG

LOUD

DISP NAME.S

PWR OFF

47W x 4

CR2

AUTO AME

CASSETTE RECEIVER

KRC-609

SERVICE MANUAL

KRC-679R/RY KRC-781R/789

The following reference numbers with accessory parts are the same reference numbers used on EXPLODED VIEW and PARTS LIST.

KRC-609 (K)

KRC-679R/RY (E)

KRC-781R (M) KRC-789 (M)

KRC-609

KRC-679R

KRC-781R KRC-789

201

277

780

RC1

276

261

222

259

278

216

DC1

DC2

AUDIO

S-METER

IFC OUT

PLL DATA

PLL CLK

SW5V

TAPE CHANGER

S METER

SDA

SCK

S MUTE

A 8V

MODE 2

SUB-

MOT+B

SUB+

MODE 1

REV (L)

FOR (R)

REV (R)

FOR (L)

R REEL

F REEL

MODE 3

SRT SW2

SRT SW1

S METER

IFC PLL DATA

PLL CLK

MS OUT

MTL ON/OFF

MODE 2 MODE 3

R REEL

MODE 1

F REEL

MS MODE

F/R

MUTE

DOLBY ON/OFF

DATA C

CH RST CH MUTE

DATA H CH CON

CH CLK REQ H REQ C

RESET

SUB -

SUB +

MOTOR

ILL ON

AM+B

FM+B

SCK

SDA

PRE MUTE

MUTE

BEEP

P MUTE

ACC DET

PHONE

DIMMER

EXT AMP CONT

P CON

P-5V

ANT CONT

B.U DET

SW5V

CH MUTE

CH RST

DATA H

DATA C

CH CON

REQ C

CH CLK

REQ H

BACK UP

1200mV

388mV

A 8V

SW5V

B.U.5V

2 SUB-

SUB+

MOT+B

A8V

B.U.5VSW5V

MUTE

AUX IN

BACK UP

SW5V

B.U.5V

1800mVTAPE

3600mV

855mV

1372mV

600mV

3600mV

1800mV

E TYPE K TYPE

1800mV

RCLK

QUAL

RD ATA

QUAL

AFS

NOISE

AFS

MTL ON/OFF

F/R

MS OUT

DOLBY ON/OFF

MUTE

MS MODE

P ON

L CE

L CLK

DIMMER

L DATA S

L DATA L

REMO

LCD

SC CON

V-ILL

MC DATA

MC CLK

MC REQ

SC DATA

P-RESET

DIMMER

TEL MUTE

ACC

ANT CON

P CON

BACK UP

EXT.AMP CONT

F/E

FM+B

BUFFER

DECODER

RDS

E-VOL

MPX

N.C.

AM+B

CASSETTE MECH

SYSTEM U-COM

CD-CHANGER MD-CHANGER

KEY

MATRIX

RESET

LCD

DRIVER

REMO

G/R SW

RESET

U-COMMATRIX

RESET

LCD

KEY

REMO

PANEL

G/R SW

DRIVER

SUB MOT

MAIN MOT

AVR

VOLTAGE LIMITTER

ILL AVR

A 8V SW14V

EXT AMP CONT

DIMMER

ACC DET

TEL MUTE

P CON

B.U DET

ANT CON

SW5V B.U.5V

P-5V

SRT

MECHA

POWER IC

THEMO

PROTECT

MUTE LOGIC

DRIVER

MUTE

SP OUT

1.8V PRE OUT

LCD

BUFFER

DOLBY EQ

TYPE

LCD

TYPE

V-ILL

LCD DRIVER

251mV(ETYPE)

470mV(KTYPE)

FM :

AM :

230mV

KRC-509S/689 (K/M) KRC-579R/RY (E) KRC-609,679R/RY,781R/789 (K/E/M) KRC-V679R/RY (E)

KRC-609,679R/RY,781R/789

BLOCK DIAGRAM

KRC-609,679R/RY,781R/789

COMPONENT DESCRIPTION

SYNTHESIZER UNIT (X14-xxxx-xx)

REF

No.

Q1-4 PREOUT MUTE SW Preouts are muted when the base level goes "H".

Q17,20 AUDIO 8V AVR Q20 is turned on when Q17's base level goes "H".

Q18 PANEL 5V SW Q45 is turned on when Q18's base level goes "H".

Q21,22 B.U. 5V AVR Q22 is turned on when Q21's base level goes "H".

Q23 SW 5V ON when the base level goes "L". Q24 BACK-UP DETECTION ON when the base level goes "H" during the back-up works.

Q25 ACC DETECTION ON when the base level goes "H" during the ACC works. Q26,27 P-ANT SW Q26 is turned on when Q27's base level goes "H". Q28-31 P-CON SW Q28 is turned on when Q31's base level goes "H".

Q32 DIMMER SW ON when the base level goes "H" while vehicle small lamps turn on. Q33,34 ILLUMINATION AVR ON when Q44's base level goes "H". Q35,36 SW 14V Q36 is turned on when Q35's base level goes "H". Q37,38 MOTOR DRIVER POWER SUPPLY Q38 is turned on when Q37's base level goes "H".

Q39 EXTERNAL AMPLIFIER CONTROL ON when the base level goes "L".

Q40 ILLUMINATION AVR ON when Q44's base level goes "H". Q41,42 MOTOR SW Q42 is turned on when Q41's base level goes "H".

Q44 ILLUMINATION AVR ON when Q44's base level goes "H".

Q45 PANEL 5V SW Q45 is turned on when Q18's base level goes "H".

Q71 PREOUT MUTE DRIVER ON when the base level goes "L".

Q72 E-VOL MUTE SW ON when the base level goes "H".

Q73 NOISE BUFFER Q86,88 AM+B SW Q88 is turned on when Q86's base level goes "H". Q87,89 FM+B SW Q89 is turned on when Q87's base level goes "H".

Q90 COMPOSITE OUTPUT BUFFER

Q92 IFC BUFFER

Q95 MSTC SW Q95 is turned on when MS mode level goes "H".

IC1 SYSTEM u-COM IC2 E-VOL / NOISE CHANCELLOR / MPX

IC4 POWER IC IC10 MUTE LOGIC IC11 RDS DECODER IC13 MOTOR DRIVER IC15 RESET IC16 DOLBY

FUNCTION OPERATION

SWITCH UNIT (X13-xxxx-xx)

REF.

No.

Q1,2 KEY DETECTION SW

Q3,4 KEY ILLUMINATION SW

Q5 LCD REFERENCE VOLTAGE SUPPLY Stabilises voltage circuit. Q6 REMOTE IC POWER SUPPLY Remote controller works when the base level goes "L".

Q7 DIMMER SW

IC1 LCD DRIVER

IC2 REMOTE SENSOR

FUNCTION OPERATION

Q1 is to start the key scan for the SRT. Q2 is to start the key scan for the M&T. Lights red key-illumination when Q3's base level goes "H". Lights green key-illumination when Q4's base level goes "H".

Usually the base level is "H". During the dimmer on, the base level goes "H" and "L" repeatedly in a moment.

KRC-609,679R/RY,781R/789

MICROCOMPUTER'S TERMINAL DESCRIPTION

(X14-) IC1 : SYSTEM µ-COM

PORT

No.

1 AM+B O AM power supply. "H" : During receiving AM. 2 FM+B O FM power supply. "H" : During receiving FM.

3 AFS O Noise detection time constant SW.

4 PLL-DATA I/O Data from and to the front-end. 5 PLL-CLK I/O Clock from and to the front-end. 6 EVDD - VDD. 7 GND - GND. 8---

9 BEEP O Beep. 10 REMOTE I Remote sensor. 11 P-ON O SW 14V control. "H" : Power on. "L" : Power off. 12 P-STBY O Power IC stand-by control. "H" : Power IC on. "L" : Power IC off. 13 IC2-SDA I/O IC2 data line. 14 IC2-SCL I/O IC2 clock line. 15 PRE-MUTE O Premute. "L" : Reset / Momentary power down. 16 17 18 TEST - Test. 19 P-CON O Power control. "H" : Power on. "L" : Power off. 20 ANT-CON O Antenna control. "H" : Tuner on, TI on.

21 MUTE O Mute.

22 - - - -

23 ACC-DET I ACC detection.

24 25 26 CH-MUTE I Mute request from the changer. "H" : Mute on. "L" : Mute off. 27 CH-CON O Changer control. "H" : Changer on. "L" : Changer off. 28 29 CH-RST O Resets the changer. "L" : Normally.

30 EXT-AMP O External amplifier control. 70mS "L" level : Bass boost LOW.

31 32 XT1 I Sub clock. 33 XT2 - Sub clock. 34 REG-C - To inner u-com's regulator

35 X2 - Main clock. Power off or Momentary power down :

36 X1 I Main clock. 37 VSS - GND. 38 VDD - VDD.

39,40 - - -

41 MOTOR O Main motor. "H" : Motor driving. "L" : Motor stopping. 42 MODE2 I Mode detection for the cassette mechanism. 43 MODE1 I Mode detection for the cassette mechanism.

44,45 - - -

46 SUB- O Sub motor. 47 SUB+ O Sub motor.

48-50 - - -

PORT NAME I/O FUNCTION OPERATING CONDITION

P-MUTE

DIM-CON/SC-CON

DIMMER

SW 5V

CH-REQ-H

RESET

O Power IC mute. "L" : Power off / All off / Tel mute. O Dimmer control or panel u-com control. "H" : Dimmer off. L : Panel off.

I Detects the small signal. "H" : Small off. "L" : Small on.

O 5V power supply. "H" : 5V off. "L" : 5V on.

O Request to the changer. "L" : During requesting.

I Reset. "H" : Normally. "L" : Reset.

"H" : During receiving. "L" : During seeking FM or searching AF.

"ON" : Open. "OFF" : Level "L". Time constant : 0.48mS.

"H" : ACC does not exist. "L" : ACC exists.

40mS "L" level : Bass boost OFF.

100mS "L" level : Bass boost HI.

Power on : During oscillating.

No oscillation.

KRC-609,679R/RY,781R/789

MICROCOMPUTER'S TERMINAL DESCRIPTION

(X14-) IC1 : SYSTEM µ-COM

PORT

No.

51 - - 52 ILLUMI-ON O Illumination. "H" : Illumination on. "L" : Illumination off.

53,54 - - -

55 BVDD - Power supply. 56 BVSS - GND. 57 - - 58 TYPE-2 I/O Destination SW. 59 TYPE-1 I/O Destination SW. 60 TYPE-0 I/O Destination SW. 61 IC2-TYPE-1 I Destination. "L" : Initial setting. 62 IC2-TYPE-0 I Destination. "L" : Initial setting. 63 - - -

65 MC-REQ/L-CE I/O Request to panel u-com. "L" : Panel on.

66,67 - - -

69 MSC O No-sound detection time constant SW.

70 AV CONT O Reference voltage control. 71 AVDD - VDD. 72 AVSS - GND. 73 AVREF I Reference voltage supply.

74 PHONE I Phone detection.

75 R-REEL I Reverse reel pulse of cassette mechanism. 76 F-REEL I Forward reel pulse of cassette mechanism. 77 SRT-SW2 I SRT mechanism position detection. 78 SRT-SW1 I SRT mechanism position detection. 79 NOISE I FM noise detection. 80 S-METER I S-meter detection. 81 R-DATA I RDS decoder data. 82 R-QUAL I RDS decoder qual. 83 IFC-OUT I Front-end IFC. "L" : Signal exists. 84 MUSIC I No-sound detection. "H" : No sound. "L" : Sound exists. 85 - - 86 DOLBY O Dolby SW. "H" : Dolby on. "L" : Dolby off. 87 R-CLK I RDS decoder clock. 88 89 SC-REQ/KEY-REQ I Request from panel u-com. 90 MODE3 I Cassette mechanism SW.

91 EQ-MUTE O Equalizer mute SW.

94 CH-DATA-C I Data from the changer. 95 CH-DATA-H O Data to the changer. 96 CH-CLK I/O Clock from and to the changer. 97 SC-DATA/L-DATA-L I Data from panel u-com. 98 MC-DATA/L-DATA-S I/O Data from and to panel u-com. 99 MC-CLK/L-CLK I/O Clock from and to panel u-com. "L" : Panel off.

100 PAN-5V O Panel 5V control. "H" : Panel on. "L" : Panel off.

PORT NAME I/O FUNCTION OPERATING CONDITION

"H" : Normally.

P-RST

FWD/REV

CH-REQ-C

NML/MTL

BU-DET

O Resets panel u-com. "L" : Rest / Panel off / Momentary power

down / U-com running out of control.

O Tape equalizer. "H" : Reverse. "L" : Forward.

"H" : Tape playing. "L" : During FF/REW, Except tape mode.

Tel mute : Under 1V. Navi mute : Over 2.5V.

I Request from the changer. "L" : request exists.

"H" : During FF/REW, Except tape mode. "L" : Tape playing.

O Normal/Metal SW. "H" : Normal. "L" : Metal.

I Momentary power-down detection.

"H" : No back-up (Momentary power down). "L" : Back-up exists.

KRC-609,679R/RY,781R/789

TEST MODE

1. How to enter the test mode While holding the FM and Preset 6 keys, reset the unit.

2. How to exit from the test mode While holding the Preset 6 key, reset the unit. (Note) The test mode cannot be terminated by ACC OFF,

power OFF or momentary power down.

3. Initial status in the test mode

• Sources : ALL OFF

• Display : All segments are lit.

• Volume : -10 dB (displayed as "30")

• Loudness : OFF

• CRSC : OFF regardless of the presence of

switching function.

• SYSTEM Q : Flat

• LED : White for no scanning. (VLCD model)

4. Special display in Tuner mode When any of the following messages is displayed in Tuner mode, the F/E may be abnormal.

• "TNE2P NG" : The EEPROM is set to the default

(unstable values) because the F/E was shipped without passing through the adjustment process, etc.

• "TNCON NG" : Communication with the F/E is not

possible.

5. Forced switching of K3I Each press of the Preset 6 key in Tuner mode should switch K3I from AUTO î Forced Wide î Forced Middle î Forced Narrow î AUTO. The initial status is AUTO and the display shows these modes as follows.

• AUTO : FMA

• Forced Wide : FMW

• Forced Middle : FMM

• Forced Narrow : FMN

6. Test mode specifications of the CD receiver

• Forced ejection is inhibited in the reset start operation.

When the unit is reset while a CD is loaded in it, the CD is not recognized by resetting.

• Each press of the Track Up key jumps to the following

track numbers: No. 9 î No. 15 î No. 10 î No. 11 î No. 12 î No. 13 î No. 14 î No. 9 (The cycle restarts from here.)

• Each press of the Track Down key jumps to the previous track number to the track being played.

7. Audio-related specifications

• A short press of the Q key initiates the audio adjustment mode.

• Pressing the îkey on the remote initiates the audio adjustment mode.

• Continuous holding of a remote control key is inhibited.

• Bass, Middle and Treble are adjusted in 3 steps of Min/Center/Max with the Track Up/Down keys.

• Balance is adjusted in 3 steps of Left Max/Center/Right Max with the Track Up/Down keys.

• Fader is adjusted in 3 steps of Rear Max/Center/Front Max with the Track Up/Down keys.

• HPF is adjusted in 2 steps of Through/220 Hz with the Track Up/Down keys.

• LPF is adjusted in 2 steps of Through/120 Hz with the Track Up/Down keys.

• Bass f, Bass Q, Bass EXT, Middle f, Middle Q and Treble f are not dealt with by the audio adjustment.

8. Menu-related specifications

• A short press of the CLK key initiates the Menu mode.

• Pressing the DNPP/SBF key on the remote initiates the Menu mode.

• Continuous holding of a remote control key is inhibited.

• Calendar adjustment, calendar display switching and calendar memo are eliminated from the targets of continuous key holding. (FL model)

• In the color adjustment mode, pressing the Preset 1 key sets Red, 2 sets Blue, 3 sets Green and 4 sets Green. (VLCD model)

• Contrast is adjusted in 3 steps of 0/5/10 and the default is 5. (VLCD/LCD model)

• Brightness is adjusted in 3 steps of 0/5/10 and the default is 10. (Normal FL model)

9. Backup current measurement When the unit is reset while ACC is OFF (i.e. by turning Backup ON), the MUTE terminal goes OFF in 2 seconds in place of 15 second. (The panel, CD mechanism and TAPE mechanism are not activated at this time.)

10. Special display when the display is all on Pressing the Preset keys while the power is ALL OFF displays the following information.

Version display (8 digits, Month/Day/Hour/Minute)

[PRESET 1] (Display) SYS xxxxxxxx System microcomputer

PAN xxxxxxxx Panel microcomputer

[PRESET 2]

Serial No. display (8 digits)

(Note) CD/RK type eXcelon model

(Display) S. No. xxxxxxxx Short press : View power ON time.

(The All OFF period is not counted.)

[PRESET 3] Long press/hold : Clear power ON time.

(Display) PonTim xxxxx Max. 65535 (hours) Short press

: Display TAPE/CD/MD operation time.

[PRESET 4] Long press/hold

: Clear TAPE/CD/MD operation time

(Display) CDTime xxxxx (CD/R)

TapTim xxxxx (C/R) Max. 65535 (hours)

Short press

: Display TAPE/CD/MD ejection count.

[PRESET 5] Long press/hold

: Clear TAPE/CD/MD ejection count.

(Display) EjeTim xxxxx Max. 65535 (times) Short press : Display Panel open/close count.

[PRESET 6] Long press/hold : Clear Panel open/close count.

(Display) PnCnt xxxxx Max. 655350 (times)

TEST MODE

KRC-609,679R/RY,781R/789

11. Other specifications

• Automatic panel closing when a tape/CD is inserted is inhibited. (M&T model)

• Panel operation by turning power OFF/ON is inhibited. (M&T model)

• Messages such as "CODE OFF" are not displayed when power is turned ON.

• Pressing the ATT key opens or closes the panel. (M&T model)

• Pressing the TI (AUTO) key during changer operation turns 2zone ON. 2zone can be turned OFF by pressing the TI (AUTO) key again. The P/S dot lights while 2zone is ON.

• Pressing and holding the CLK key for a second in the ALL OFF status the Mask Key (security) write mode.

• Security-related information

1. Forced Power ON mode (All models) Even when the security (Mask key) is approved, resetting the unit while holding the ATT and Preset 4 keys makes it possible to turn the power ON for 30 minutes. After 30 minutes have elapsed, it is not possible to return to the previous condition unless the unit is reset again.

2. Method of registration of the security code after EEPROM

(Tuner Unit Ass'y) replacement (Code security model)

(1) Enter the test mode. (See " 1. How to enter the test

mode")

(2) Press the CLK key to enter the security registration

mode.

(3) Enter the code using the Preset 1/2/3/4 keys.

Example: To enter "3510"

• Press the Preset 1 key 4 times.

• Press the Preset 2 key 6 times.

• Press the Preset 3 key twice.

• Press the Preset 4 key once.

(4) Press and hold the DISP key for 3 seconds until

"APPROVED" is displayed.

(5) Exit from the test mode. (See " 2. How to exit from the

test mode")

(Note) All Clear is not applicable to the security code of

this model.

3. Simplified method of clearing the security code (K Type

only)

(1) While the code entry is requested, press and hold the

VOL UP key for 3 seconds while holding the DISP key pressed. (This should turn "----" off.)

(2) Enter "KCAR" from the remote. (Same way as the 00

model) Press the 5 key on the remote twice, then press the Track Up key. (This enters "K".) Press the 2 key on the remote 3 times, then press the Track Up key. (This enters "C".) Press the 2 key on the remote once, then press the Track Up key. (This enters "A".) Press the 7 key on the remote twice, then press the Track Up key. (This enters "R".)

(3) The security code is cleared and the unit enters the

ALL OFF mode.

(4) If you commit a mistake in the code entry, the unit

enters the code request mode again.

4. Method of writing the Mask key while the EEPROM is in the initial status

(1) Enter the test mode. (See " 1. How to enter the test

mode")

(2) Press the CLK key to enter the Mask key registration

mode. "TRANSMIT1" should be displayed now. The display at this time should show " < > " in place of " [ ] ".

(3) Point the Mask key remote toward the light sensor,

and press and hold its key for more than 0.5 second.

(4) When "TRANSMIT2" is displayed, press and hold the

key on the Mask key remote for more than 0.5 second again. The first and second counter codes are not compared at this time.

(5) When "APPROVED" is displayed, the write operation

is complete. Now the demonstration mode is initiated and the test mode is terminated.

(Note) In the same way as previous models, if 30 minutes

have elapsed with no code written, an error occurs and the power is turned OFF.

5. Method of initializing the Mask key

(How to reset the unit from the Mask key approved condition to the factory condition)

(1) Enter the test mode. (See " 1. How to enter the test

mode")

(2) "TRANSMIT1" is displayed and the Mask key entry

request mode is initiated. The display at this time should show " ✽ ✽" in place of " [ ] ".

(3) Press and hold the key on the Master key remote for

more than 3 seconds.

(4) When "TRANSMIT2" is displayed, press and hold the

key on the Master key remote for more than 3 seconds again.

(5) When "APPROVED" is displayed, the Mask key is

cleared, the demonstration mode is initiated, the test mode is terminated and the unit returns to the factory condition.

6. Method of clearing all Mask key-related data

(1) Enter the test mode. (See " 1. How to enter the test

mode")

(2) Press the CLK key to enter the Mask key registration

mode. "TRANSMIT1" should be displayed now.

(3) Point the Master key remote toward the light sensor,

and press and hold its key for more than 3 seconds (until the level display shows the full condition).

(4) When "TRANSMIT2" is displayed, hold the key on the

Mask key remote for more than 3 seconds again. If "TRANSMIT1" is displayed in place of "TRANSMIT2", restart the procedure from step (3).

(5) When "APPROVED" is displayed, all security data is

cleared and the unit returns to the condition before Mask key writing with the EEPROM in the initial status.

TEST MODE

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