Kenwood KRC-778R, KRC-PS978R, KRC-778RV, KRC-778RY, KRC-778RYV Service Manual

KRC-PS978R

KRC-878R

KRC-778R

B.S/

MTL/

DISP

B.S/

MTL/

DISP

KRC-778R/RV/RY/RYV, 878R, PS978R

CASSETTE RECEIVER

SERVICE MANUAL

2000-2 PRINTED IN KOREA

B51-7589-00 ( K ) 1889

KRC-PS978R

KRC-878R

KRC-778R

Front glass (B10-3095-01)

Escutcheon assy (B07-2146-03)

Panel assy (A64-1854-02)

Front glass (B10-3096-01)

Escutcheon assy (B07-2139-03)

Front glass KRC-778R/RY : (B10-3097-01) KRC-778RV/RYV : (B10-3098-01)

Escutcheon assy (B07-2139-03)

Panel assy (A64-1855-02)

Panel assy KRC-778R/RY : (A64-1856-02) KRC-778RV/RYV : (A64-1952-02)

Torsion coil spring (G01-2924-04)

Lever (D10-4301-14) (D10-4302-14)

Antenna adaptor (T90-0523-05)

Remote controller assy (A70-0886-15)

Screw set (N99-1683-05)

Remote controller assy (A70-0874-05)

Mounting hardware assy (J21-9491-03)

DC cord KRC-PS978R,878R,778R/RY : (E30-4788-05) KRC-778RV/RYV : (E30-4789-05)

Plastic cabinet assy (A02-1489-03)

The CASSETTE MECHANISM OPERATION DESCRIPTION is the same model D40-1122-05. Please refer to the service manual for model D40-1122-05(B51-7452-00).

40%

FM+B

AM+B

E2PROM

DIMMER TEL-MUTE

ACC DET.

SRMMECHA

BU DET.

DRIVER

LCD

SUB DRIVER

A 8V

SUB MOT

SW14V

ILL AVR

SW5V B.U.5V P CON

DRIVER

SYSTEM E'S

POWER IC

IC4

IC14

Q32

Q23 Q21,22 Q28,29,31

Q25

Q24

SYSTEM u-COM

IC1

Q18-20

Q37,38

MECH

CHANGER

IC10

IC1,2

Q35,36

Q33,40,44

Q1-6

IC5

IC2

F/E

MECHADET.

IC13

E-VOL

Q87,89

Q86,88

SP-OUT

ILL TEL-MUTE

ACC

P CON

BACK UP

RDS DECODER

IC11

AMP

IC12 NOISE

REMO

IC3

G/A SW

VLCD

4.5V PRE OUT

EXT. AMP CONT

Q39

EXT. AMP CONT

AVR

RST SW

RESET

IC15

POSISTOR

BACK LIGHT

LCD

MAIN MOT AVR

Q41,42

DC/DC

IC6

(FOR 4.5V PRE)

4.5V PRE AMP

Q26,27

CON

ANT

ANT CON

IC6

1.8V PRE OUT

WIDE/ NARROW

Q82

N.C. MPX

MUTE

MUTE LOGIC

P-5V

Q57-62

MOT

SRM

DIMMER

MD-

CD-

CASSETTE

Depeds on the model. Refer to the parts list.

PLL CLK

CHANGER

F/R

TAPE IN

MODE 3

MODE 1

R REEL

MTL ON/OFF

DOLBY ON/OFF

MODE 2

F REEL

MS MODE

MUTE

DOLBY B/C

CH CLK

CH CON

DATAC

REQ H

CH RST

REQ C DATAH

TAPE

MUTE

RESET

SRM SW1

SRM DET

SRM SW2

SUB MOT1

RCLK

QUAL

RDATA

FM+B

SDA

SCK

A8V

SW5V

PLL DATA

PLL CE

FM SD

FSD OUT

REQUEST

RDS OUT

SW5V

FM+B

AM+B

S METER

FM SD

NARROW IF MODE PLL CE

NOISE

CH MUTE

BACK UP

SW5V

S METER

P MUTE

EXT. AMP CONT

AC GND

DIMMER

PHONE

ACC DET

P CON

BU DET

BEEP

SW5

P-ON

L CLK

L DATAS

L CE

L DATAL

LOCK SW

DIMMER

REMO

BU5V

160mV

1200mV

388mV

ILL ON

213mV

MS OUT

MODE 1 MODE 3

TAPE IN

MODE 2

DOLBY ON/OFF

DOLBY B/C

MTL ON/OFF MS MODE

R REEL F REEL

F/R

MUTE

MS OUT

400mV: (K) TYPE

: (E) TYPE

CASS/SRM

SUB MOT2

SUB MOT3

MOTOR

B B

ANT CON

MUTE

-B

(K) TYPE(E) TYPE

3600mV 3600mV

855mV 600mV

TAPE

1372mV 1800mV

1800mV 1800mV

(K) TYPE(E) TYPE

1715mV

2250mV

4500mV

1069mV

FM AM

TAPE

4500mV

2250mV

2250mV 750mV

SUB+

SUB-

MOT+B

IF SELECT

SW5V

AFC

B.U.5V

BACK UP

SW5V

PRE MUTE

S MUTE

P-5V

SW5V B.U.5V

A 8V

ILL

REQ H

CH MUTE

CH RST

CH CON

REQ C DATAH

DATAC

CH CLK

IF MODE

WIDE

PLL DATA PLL CLK

SW5V

SUB-

SUB+

MOT+B

SW 5V

A 8V

SCK

SDA

SCK

(X13- )

KRC-X858

KRC-778R/RY

KRC-PS988R KRC-708

KRC-PS978R KRC-888

KRC-778RV/RYV KRC-878R

KRC-778R/RV/RY/RYV,878R,PS978R

BLOCK DIAGRAM

UPD784217GC103(105) (IC1: X14-618X-XX) System MicroComputer

Pin Pin Name Signal Name I/O Purpose Operation Description

1 P120/RTP0 CHCON O Changer control terminal. ON:Hi, OFF:Lo 2 P121/RTP1 CH_MUTE I Muting input to changer. ON:Hi, OFF:Lo 3 P122/RTP2 REQH O Handshake request to changer. 4 P123/RTP3 DIMMER I Small detection. DIMMER ON:Lo, OFF:Hi

5 P124/RTP4 MOTER O

Cassette mechanism main motor output.

Active; Hi.

6 P125/RTP5 NC O 7 P126/RTP6 NC O 8 P127/RTP7 NC O

9 Vdd Vdd - Positive power supply. 10 X2 X2 - Main clock connection. 11 X1 X1 - Main clock connection. 12 Vss Vss - GND terminal. 13 XT2 XT2 - Sub-clock connection. 14 XT1 XT1 - Sub-clock connection. 15 RESET RESET I Reset input. Active: Lo. 16 P00/INTP0 CH_RST O Reset output to changer. Active: Hi. 17 P01/INTP1 R_CLK I RDS clock input. 18 P02/INTP2/NMI REQC I Handshake request from changer. 19 P03/INTP3 KEY REQ I 20 P04/INTP4 SUB_MOTOR3 O Sub-motor output. 3 21 P05/INTP5 SUB_MOTOR2 O Sub-motor output. 2 22 P06/INTP6 SUB_MOTOR1 O Sub-motor output. 1 23 AVdd Avdd - A/D analog power supply. 24 AVref0 AVref0 - A/D reference voltage input.

25 P10/ANI0 PHONE I Phone detection.

1 V or less: TEL MUTE /2.5 V or more: NAVI MUTE.

26 P11/ANI1 SRM_SW1 I SRM position detection. Open: Hi. 27 P12/ANI2 NOISE I FM noise detection. 28 P13/ANI3 SMETER I FM S meter detection.

29 P14/ANI4 F_REEL I

Cassette mechanism reel pulse input (FWD).

30 P15/ANI5 R_REEL I

Cassette mechanism reel pulse input

(REV). 31 P16/ANI6 N.C. I 32 P17/ANI7 N.C. I 33 AVss AVss - A/D GND terminal.

34 P130/ANO0 EXT_AMP O External amp control.

L 40mS:Bass boost OFF L 70mS:Bass boost LOW L 100mS:Bass boost Hi

35 P131/ANO1 IF_MODE I IF status detection for K2I. Hi = WIDE, Lo = NARROW 36 AVref1 AVref1 - D/A reference voltage input. 37 P70/RxD2/SI2 DATAC I Data line from changer. 38 P71/TxD2/SO2 DATAH O Data line to changer. 39 P72/ASCK2/SCK2 CH_CLK I/O Clock line with changer. 40 P20/RxD1/SI1 L_DATAL I Data line from LCD driver. 41 P21/TxD1/SO1 L_DATAS O Data line to LCD driver. 42 P22/ASCK1/SCK1 L_CLK O Clock line to LCD driver. 43 P23/PCL DIMMER O Dimmer control output. 44 P24/BUZ BEEP O Beep output. Active: Hi. 45 P25/SI0 PLL_CE O CE to PLL. 46 P26/SO0 PLL_DATA I/O Data input/output with PLL. 47 P27/SCK0 PLL_CLK O Clock output to PLL. 48 P80/A0 ILL_ON O ILL ON ILL ON : Hi

49 P81/A1 PANEL_5V O

5V power supply control for LCD

driver.

Active: Lo.

50 P82/A2 L_CE O CE terminal to LCD driver 51 P83/A3 LOCK_SW I Panel lock SW detection terminal. Lock SW ON : Lo

KRC-778R/RV/RY/RYV,878R,PS978R

MICROCOMPUTER TERMINAL DESCRIPTION

UPD784217GC103(105) (IC1: X14-618X-XX) System MicroComputer

Pin Pin Name Signal Name I/O Purpose Operation Description

52 P84/A4 WIDE O K2I Forced Wide output. H:Forced Wide 53 P85/A5 NARROW I/O K2I Forced Narrow output. H:Forced Narrow

54 P86/A6 AFC I Noise detection time constant SW 55 P87/A7 SRM_SW2 I SRM eject position detection. EJECT:Hi

56 P40/AD0 QUAL I RDS reception quality. 57 P41/AD1 R_DATA I RDS data input. 58 P42/AD2 SRM_DET I SRM mechanism detection. Detected: Lo /Not detected: Hi.

59 P43/AD3 FM_SD I FM SD input.

Station detected: Hi /Not detected: Lo.

60 P44/AD4 N.C. O 61 P45/AD5 MUSIC I Blank detection input.

Music detected: Lo /Music not detected: Hi.

62 P46/AD6 B/C O Dolby B/C switching. B = Lo, C = Hi 63 P47/AD7 Dolby O Dolby output. ON : Hi, OFF : Lo 64 P50/A8 EQ_MUTE O EQ muting output. During play: Lo /FF or REW: 65 P51/A9 MTL O Metal output. NOMAL : Hi, METAL : Lo 66 P52/A10 F/R O Tape EQ input switching. FWD:Lo, REW:Hi

67 P53/A11 MSC O

Blank detection time constant

switching.

During play: Hi /FF or REW:

Lo. 68 P54/A12 MODE3 I Cassette mechanism mode detection. 69 P55/A13 MODE1 I Cassette mechanism mode detection. 70 P56/A14 MODE2 I Cassette mechanism mode detection. 71 P57/A15 PACK_DET I Cassette mechanism pack detection. Pack detected: Lo. 72 Vss GND - GND terminal. 73 P60/A16 TYPE0 I Destination type terminal 0. 74 P61/A17 TYPE1 I Destination type terminal 1. 75 P62/A18 TYPE2 I Destination type terminal 2. 76 P63/A19 ST_TYPE0 I IC2 Ver.3 destination type terminal 0. 77 P64/RD ST_TYPE1 I IC2 Ver.3 destination type terminal 1. 78 P65/WR N.C. O Not used. 79 P66/WAIT N.C. O Not used. 80 P67/ASTB N.C. O Not used. 81 Vdd Vdd - B.U.5V 82 P100/TI5/TO5 SVR O SVR discharge control. POWER OFF:Hi 83 P101/TI6/TO6 PREMUTE O PRE mute. Active: Lo. 84 P102/TI7/TO7 PMUTE O Power IC muting. P IC ON : Hi

85 P103/TI8/TO8 CASS/SRM O

Cassette mechanism / SRM mechanism voltage SW terminal.

C mech.:Hi, SRM mech.:Lo 86 P30/TO0 ANT_CON O Antenna control. Active: Hi.

87 P31/TO1 AM+B O AM power supply. Active: Hi. 88 P32/TO2 FM+B O FM power supply. Active: Hi. 89 P33/TI1 P_CON O Power control. Active: Hi. 90 P34/TI2 ACC_DET I Acc detection. Acc OFF:Hi. 91 P35/TI00 REMO I Remote control input. 92 P36/TI01 P_ON O Power supply control. POWER ON:Hi 93 P37 BU_DET I Momentary power down detection. Power down: Hi. 94 TEST TEST - Test terminal. 95 P90 IC2_SDA I/O IC2, IC5 and EEPROM data line. 96 P91 IC2_SCK O IC2, IC5 and EEPROM clock line. 97 P92 MUTE O Muting terminal. OPEN:MUTE ON 98 P93 SW5V O 5 V power supply. Lo=SW5 ON 99 P94 N.C. O Not used.

100 P95 N.C. O Not used.

KRC-778R/RV/RY/RYV,878R,PS978R

MICROCOMPUTER TERMINAL DESCRIPTION

During reception: Hi /During search: Lo.

KRC-778R/RV/RY/RYV,878R,PS978R

TEST MODE

2000 MODEL

(1) How to enter the test mode

Reset the set while holding the FM and preset 6 keys depressed. All indications light up at the moment the test mode starts.

(2) How to exit from the test mode

Reset the set while holding the preset 6 key.

(Note) The test mode is not canceled by turning Acc OFF,

turning power OFF or causing momentary power down.

(3) FM S meter voltage adjustment

1. Enter the test mode.

2. While holding the preset 1 key depressed, press and hold the preset 6 key.

3. "ADJ OK" is displayed when the result is OK or "ADJ NG" is displayed when it is No Good.

(4) AM SD voltage write

1. Enter the test mode.

2. While holding the preset 1 key depressed, press and hold the preset 6 key to write the SD voltage data.

(5) Forced Auto/Manual switching of K2I

Press and hold the TI key in the TUNER mode to switch between AUTO and MANUAL. The initial status is MANUAL, which is indicated by the lighting of the TI dots.

(6) Forced Narrow/Wide switching of K2I

Press the preset 6 key in the TUNER mode to switch between Forced Narrow and Wide. The initial status is Wide, which is indicated by the lighting of the NEWS dot.

(7) TAPE test mode specification

o The blank skip function is initially turned off.

(8) Audio adjustments

o The volume should be set to -10 dB (displayed as "30"). o The bass/treble and balance/fader controls are set to

full boost/full cut and full front/full rear respectively by single press of the UP/DOWN key.

o The high-pass filter is set to Through/100 Hz/200 Hz by

each press of the UP key, or to 200 Hz/100 Hz/Through by each press of the DOWN key.

(9) Back-up current measurement

When the set is reset while Acc is off (i.e. when the backup power is on) or when Acc is turned off in the middle of test mode, the MUTE pin turns ON in 2 seconds instead of 15 seconds. (The panel/CD/C/MD mechanism is not activated at this time.)

(10) Procedure for security code registration after

the E2PROM replacement during servicing (KRC-888 only)

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

2. Press the SRC key to select ALL OFF.

3. Press and hold the AUDIO key for 1 second to enter the menu mode.

4. Press the FM/AM key to select "SECURITY".

5. Press and hold the Track UP/DOWN key for 2 seconds.

6. Enter the security code by pressing the preset 1, 2, 3 and 4 keys.

Example: To enter "3510"

- Press preset key "1" 4 times.

- Press preset key "2" 6 times.

- Press preset key "3" 2 times.

- Press preset key "4" 1 time.

7. Press and hold the DISP key for 3 seconds so that "APPROVED" is displayed.

8. Exit from the test mode (see "(2) How to exit from the test mode").

(11) Simplified security code clear procedure

(KRC-X858, KRC-708)

1. During the code request mode, while holding the DISP key depressed, press and hold the Volume UP key for 3 seconds (so that "----" disappears).

2. Enter "KCAR" from the remote control unit. (Same operation as with the '98 models)

- Press numeric key "5" 2 times and press the Track UP key (to enter "K").

- Press numeric key "2" 3 times and press the Track UP key (to enter "C").

- Press numeric key "2" 1 time and press the Track UP key (to enter "A").

- Press numeric key "7" 2 times and press the Track UP key (to enter "R").

3. The security is canceled and the set enters the TUNER mode.

(12.1) MASK key write procedure in production line

(when the E2PROM is in the initial status)

1. While holding the FM and preset 6 keys depressed, press RESET to enter the test mode.

2. Press and hold the AUDIO key for 1 second to enter the menu mode.

3. Press the FM or AM key to select "Mask key".

4. Press the Track UP/DOWN key shortly so that "TRANSMIT1" is displayed.

5. Point the MASK key to the light sensor and press and hold the key for more than 0.5 second.

6. When "TRANSMIT2" is displayed, press and hold the MASK key again for more than 0.5 second. Note that the first and second counter codes are not compared at this time.

7. The write operation is complete when "APPROVED" is displayed. At this time, the demonstration mode is set and the test mode is canceled.

(Note) Similarly to the '98 models, leaving the set for more

than 30 minutes without writing the code causes an error and turns power off.

KRC-778R/RV/RY/RYV,878R,PS978R

TEST MODE

(12.2) Procedure for canceling the MASK key

request (when the set is reset or the back-up power is turned off while the MASK key is enabled)

1. When the power is supplied and the set is switched on, "TRANSMIT1" is displayed and the MASK key request mode starts.

2. Point the MASK key toward the light sensor and press and hold for more than 3 seconds (until the level indicator indicates the full condition).

3. When "TRANSMIT2" is displayed, press and hold the MASK key again for more than 3 seconds.If "TRANSMIT1" is displayed now, go back to step 2 and restart from there again.

4. When "APPROVED" is displayed, the MASK key is enabled and the set is turned on.

(12.3) Procedure for MASK key initialization

(Resetting the MASK key enabled condition to the factory-set condition)

1. While holding the FM and preset 6 keys, press RESET to enter the test mode.

2. "TRANSMIT1" is displayed and the MASK key request mode starts.At this time, the display shows "* *" in place of "[ ]".

3. Press the MASK key cancel remote control for more than 3 seconds.

4. When "TRANSMIT2" is displayed, press and hold the MASK key again for more than 3 seconds.

5. When "APPROVED" is displayed, the MASK key is canceled, the demonstration mode is set, the test mode is canceled and the set returns to the factory-set condition.

(12.4) MASK key all-clear procedure

1. While holding the FM and preset 6 keys, press RESET to enter the test mode.

2. Press and hold the AUDIO key for more than 1 second to enter the menu mode.

3. Press the Track UP/DOWN key to select "Mask key".

4. Press and hold the FM or AM key for more than 2 seconds so that "TRANSMIT1" is displayed.

5. Point the MASK key cancel remote control toward the light sensor and press for more than 3 seconds (until the level indicator indicates the full condition).

6. When "TRANSMIT2" is displayed, press and hold the MASK key again for more than 3 seconds.If "TRANSMIT1" is displayed now, go back to step 2 and restart from there again.

7. When "APPROVED" is displayed, the E2PROM is cleared entirely and the condition in "(14) MASK key write procedure in production line (when the E2PROM is in the initial status)" returns.

(13) Other

o Automatic panel closing when the TAPE/CD/MD is

inserted is disabled.

o Pressing the ATT key ON/OFF opens or closes the

panel. (The ATT operation can be activated from the remote control unit.)

o The DNPP/SBF key of the remote control unit (RC-510)

functions as the menu mode ON/OFF key.

o The OPEN/CLOSE key of the remote control unit (RC-

510) functions as the audio adjustment mode ON/OFF key.

o The menu feed operations occur only with the necessary

features.

o Display such as "CODE OFF" is not displayed at the

moment power is turned on.

o Pressing the TI (AUTO) key during the changer opera-

tion turns 2zone on, and pressing the TI (AUTO) key again cancels it. The P/S dot lights during the 2zone operation.

o Pressing and holding the MENU key for more than 1

second while ALL OFF initiates the MASK KEY write mode.

o The dimmer control of the FL models or the contrast

control of the LCD models can be adjusted only to 0/5/10 using the UP/DOWN keys.

KRC-778R/RV/RY/RYV,878R,PS978R

No ITEM INPUT SETTINGS

OUTPUT

SETTINGS

TUNER

(RECEIVER)

SETTINGS

ALIGNMENT

POINTS

ALIGN FOR FIG.

FM SECTION

SEPARATION

(NARROW)

98.1MHz 1kHz,±40kHz dev Pilot:±6.0kHz dev

Selector:L or R

60dBµ (ANT input)

Connect a

AC voltmeter

to SP OUT

TEST MODE:ON

(Forced Narrow)

FM 98.1MHz

VR1

(X14-)

Adjust it so that the crosstalk from L to R and R to L become minimum.

S METER

VOLTAGE

35dBµ (ANT input)

–

TEST MODE: ON

98.1MHz

Preset "1" key,

and

preset "6" key

While holding preset "1" key, press and hold preset "6" key for a few seconds. "ADJ OK" is displayed if the adjustment is OK and "ADJ NG" is displayed if it is not good.

AM SECTION

(1) SD VOLTAGE

990 kHz 0% mod

35dBµ (ANT input)

–

TEST MODE: ON

990 kHz

Preset "1" key,

and

preset "6" key

While holding preset "1" key, press and hold preset "6" key for a few seconds. "ADJ OK" is displayed if the adjustment is OK and "ADJ NG" is displayed if it is not good.

CASSETTE DECK SECTION

[1] AZIMUTH

TCC-153

10kHz

Connect a

AC voltmeter

to SP OUT

TAPE PLAY

Head Azimuth

Screw

Adjust the azimuth for

each Lch/Rch or

FWD/RVS becomes

maximum

[2]

PLAY BACK

LEVEL

TCC-130

Connect a

AC voltmeter

to CN2

TAPE PLAY

VR1 (L)

VR2 (R)

(X87)

387.5mV (-6dBm) (a)

TEST MODE : ON While holding the "FM" key and preset "6" key, reset the unit. (Forced Narrow) Press "SRC" key. Tuner mode ON.

Press preset "6" key. "NEWS" goes OFF.

Set the controls and switches as follows. BALANCE :center position BASS :center position LOUD :OFF DOLBY NR :OFF

FADER :center position TREBLE :center position

98.1MHz 0 dev

VR2 (R ch)

L G R

VR1 (L ch)

F/E

X87-301X-XX

X14-618X-XX A/2

(a) 387.5mV

AC voltmeter

CN2

VR1 (sep.)

ADJUSTMENT

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