Jvc KS-FX8-R Service Manual

SERVICE MANUAL

CASSETTE RECEIVER

KS-FX8R

Contents

Safety precaution Disassembly method Adjustment method Description of major ICs

SCM

40Wx4

DISP

RDS

PTY

789101112

KS-FX8RKS-FX8R

DOLBY B NR

RND

SSM

RPT

DAB

TAPE

FM/AM

-CH

Area Suffix

E Continental Europe

1-2 1-3 1-10 1-14

No.49580

Jan. 2001

KS-FX8R

Safety precaution

Burrs formed during molding may be left over on some parts of the chassis. Therefore, pay attention to such burrs in the case of preforming repair of this system.

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Disassembly method

Removing the front panel unit

(See Fig.1)

Press the release switch and remove the front panel unit in the direction of the arrow.

Removing the front chassis (See Fig.2~3)

Remove the two screws A attaching the front chassis.

KS-FX8R

Front panel unit

Fig.1

Joint c

Insert a screwdriver to the two joints a on the left side of the front chassis, two joints b on the right side and one joint c from upside, then detach the front chassis toward the front side.

Joint a

Fig.2

Front chassis

Fig. 3

Front chassis

Joint b

Removing the heat sink (See Fig.4)

Remove the three screws B attaching the heat sink on the left side of the body, and remove the heat sink.

Heat sink

Fig. 4

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KS-FX8R

Removing the bottom cover (See Fig.5)

Prior to performing the following procedure, remove the front chassis and the heat sink.

Turn the body upside down.

Insert a screwdriver to the two joints d and two joints e on both sides of the body and the joint f on the back of the body, then detach the bottom cover from the body.

Removing the rear panel (See Fig.6 )

Prior to performing the following procedure, remove the front chassis, the heat sink and bottom cover.

Joints d

Bottom cover

Joints e

Joint f

Fig. 5

Remove the five screws C attaching the rear panel and one screw D attaching the pine jack on the back of the body.

Rear panel

Removing the main amplifier board assembly

(See Fig.7)

Prior to performing the following procedure, remove the front chassis, the heat sink, bottom cover and the rear panel.

Remove the two screws E attaching the main amplifier board assembly on the top cover.

Fig. 6

CP401

Disconnect connector CP401 on the main amplifier board assembly from the cassette mechanism assembly.

1-4

Main board assembly

Fig. 7

Removing the cassette mechanism assembly

(See Fig.8)

Prior to performing the following procedure, remove the front chassis, the heat sink, bottom cover and the main amplifier board assembly.

Remove the four screws F attaching the cassette mechanism assembly from the top cover.

Cassette mechanism assembly

KS-FX8R

Removing the (LCD & key) control switch board (See Fig.9 and 10 )

Remove the front panel unit from the main body.

Remove the five screws G attaching the rear cover on the back of the front panel unit.

Remove the control switch board from the front panel unit.

Fig. 8

LCD & Key control board

Fig. 9

Top cover

Fig. 10

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KS-FX8R

Cassette mechanism ass’y

Removing the head amplifier board.

(See Fig.1 and 2)

For the 6pin wire extending from connector CN402 on the head amplifier board, disconnect it from the head relay board.

Disconnect the card wire from connector CN403 on the head amplifier board.

Remove the screw A attaching the head amplifier board.

Move the tab a as shown in Fig.2 and remove the head amplifier board while moving it in the direction of the arrow.

Removing the cassette mechanism assembly (See Fig.1 to 3)

Disconnect the 6pin wire from connector CN402 and the card wire from CN403 on the head amplifier board (Refer to Fig.1 and 2).

Head relay

board

6pin wire

CN402

CN403

CN402

Fig.1

CN403

Head amplifier board

Fig.2

Head amplifier board

Tab a

Remove the four screws B on the bottom of the cassette mechanism.

Head amplifier board

Cassette mechanism ass’y

Fig.3

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KS-FX8R

Removing the head relay board

(See Fig.4)

Unsolder the soldering b on the head relay board.

Remove the screw C attaching the head relay board.

Remove the head relay board in the direction of the arrow while releasing the two joints c.

Removing the load arm (See Fig.5)

Remove the E washer attaching the load arm using a pincette or something like that and remove the spring d.

Move the part of the load arm marked upwards to release it from the axis of rotation. Then rotate the load arm in the direction of the arrow to remove it from the cach.

Fig.4

Cach

Load arm

Fig.5

Head relay board

Soldering b

E washer

Joint c

Spring d

Removing the sub chassis (See Fig.6)

Prior to performing the following procedure, remove the head relay board.

Remove the screw D attaching the sub chassis.

Push the tab e in the direction of the arrow to detach the one side of the sub chassis. Then release the sub chassis from the tab f.

Removing the cassette holder and the holder arm in the eject mode

(See Fig.7 and 8)

Prior to performing the following procedure, remove the head relay board, the load arm and the sub chassis.

Remove the screw E attaching the reinforce bracket.

Remove the reinforce bracket.

Tab f

Sub chassis

Head relay

board

Cassette mecha chassis

Cassette holder

Fig.6

Head relay board

Tab e

Reinforce bracket

tab g

Push the tab g fixing the cassette holder in the direction of the arrow and open the cassette holder and the holder arm upward until they stop at an angle of 45 degrees. Move the two joints h to the side and remove the cassette holder and the holder arm from the shaft.

Joint h

Load arm

Holder arm

Fig.7

Joint h

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KS-FX8R

Removing the flywheel

(See Fig.10 and 12)

Prior to performing the following procedure, remove the head relay board, the load arm, the sub chassis, the cassette holder, the holder arm and the reel disc board.

Remove the belt on the bottom of the cassette mechanism ass’y.

Remove the slit washer attaching the flywheel on the upper side of the cassette mechanism ass’y and pull out the flywheel downward. Then remove another flywheel in the same way.

ATTENTION:

When reassembling, make sure to use a new slit washer.

Removing the reel disc ass’y( I )

(See Fig.12 to 14)

Soldering j

Motor

Plate

Reel disc board

Slit washer

Tab k

Tab o

Cassette mechanism ass’y

Tab k

Belt

Fig.10

Reel driver

The part n

Tabs o

Flyhwheel

Reel disc

ass’y( I )

Push aside the gear

Prior to performing the following procedure, remove the head relay board, the load arm, the sub chassis, the cassette holder and the holder arm.

Disengage the part n inside of the reel driver which engages with the shaft, using a pincette or something like that. Then remove the reel driver from the shaft.

Remove the reel driver spring and the reel table.

The part n

Slit washer

Shaft

Fig.13

The part n

Reel driver

Fig.12

Reel driver

Reel driver spring

Reel disc ass’y( II )

1-8

Reel table

Fig.14

KS-FX8R

Removing the reel disc ass’y( II )

(See Fig.12 to 15)

ATTENTION:

Release the plate from the three tabs o.

Push aside the gear over the reel table using a pincette or something like that.

Remove the reel disc ass’y ( II ) as with the reel disc ass’y ( I ).

ATTENTION:

Prior to performing the following procedure, remove the reel disc ( I ).

Do not break the front panel tab fitted to the metal cover.

Push aside the gear and reattach the reel disc Ass’y( I ).

Reel disc ass’y( II )

Fig.15

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KS-FX8R

Adjustment method

Test Instruments reqired for adjustment

1. Digital osclloscope(100MHz)

2. Frequency Counter meter

3. Electric voltmeter

4. Wow & flutter meter

5. Test Tapes

VT724 ....................... for DOLBY level measurement

VT739 ............ For playback frequency measurement

VT712 ....For wow flutter & tape speed measurement

VT703 ..................... For head azimuth measurement

6. Torque gauge .................... Cassette type for CTG-N

(mechanism adjustment)

Measuring conditions(Amplifier section)

Power supply voltage .............. DC14.4V (10.5 - 16V)

Load impedance ........... 4 (2Speakers connection)

Line out............................................................ 20k

Standard volume position

Balance and Bass,Treble volume .Fader :Center(Indication"0") Loudness,Dolby NR,Sound,Cruise:Off Volume position is about 2V at speaker output with following conditions.Playback the test tape VT721.

AM mode 999kHz/62dB,INT/400Hz,30%

modulation signal on recieving.

FM mono mode 97.9MHz/66dB,INT/400Hz,22.5kHz

deviation pilot off mono FM stereo mode 1kHz,67.5kHz dev. pilot7.5kHz dev. Output level 0dB(1 V,50 /open terminal)

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Arrangement of adjusting & test points

Cassette mechanism (Surface)

Motor assembly

Tape speed adjust

KS-FX8R

Playback head

Head section view

Azimuth screw

Head azimuth screw

Fixed screw

Playback head

Height adjusting screw c

Height adjusting screw b

Height adjusting screw a

1-11

KS-FX8R

Information for using a car audio service jig

1. For 1995 and 1996 , we're advancing efforts to make our extension cords common for all car audio products. Please use this type of extension cord as follows.

2. As a U-shape type top cover is employed, this type of extension cord is needed to check operation of the mechanism assembly after disassembly.

3. Extension cord : EXTKSRT002-6P ( 6 pin extension cord ) For connection between mechanism assembly and main board assembly. Check for mechanism driving section such as motor ,etc..

Disassembly method

1. Remove the bottom cover.

2. Remove the front panel assembly.

3. Remove the top cover .

4. Install the front panel.

5. Confirm that current is being carried by connecting an extension cord jig.

Note Available to connect to the CN701 connector when installing the front panel.

Cassette mechanism

EXTKSRT002-6P

Extension cord : EXTKSRT002-6P

Main board

Front panel assembly

1-12

Mechanism adjustment section

Item Adjusting & Confirmation Methods Adjust Std. Value

1.Head azimuth

"Head Height Adjustment" Note

Adjust the azimuth directly. When you adjust the height using a mirror tape, remove the cassette housing from the mechanism chassis. After installing the cassette housing, perform the azimuth adjustment.

1.load the mirror tape ( SCC-1659 ). Adjust with height adjustmentscrew (a) and azimuth adjustment screw (b) so that line "A" of the mirror tape runs in the center between Lch and Rch in the reverse play mode.

2.After switching from REV to FWD then to REV, check that the head position set in procedure "1" is not changed. *If the position has shifted, adjust again and check.

3.Adjust the azimuth screw (b) so that line "B" of the mirror tape runs in the center between Lch and Rch in the forward play mode.

"Head Azimuth Adjustment"

1.Load the test tape ( VT724: 1kHz ) and play it back in the reverse play mode. set the Rch output level to maximum.

2.Load the test tape ( VT703: 10kHz ) and play it back in the forward play mode. Adjust the Rch and Lch output levels tomaximum, with azimuth adjustment screw (b).

In this case, the phase difference should be within 45 .

3.Engage the reverse mode and adjust the output level to maximum, with azimuth adjustment screw (c). *The phase difference should be 45_Kor more.

4.When switching between forward and reverse modes, the difference between channels should be within 3dB. *Between FWD Lch and Rch, REV Lch and Rch.

5.When the test tape ( VT721 : 315Hz ) is played back, the level difference between channels should be within 1.5dB.

Head shield

The head is at low position during FWD.

Head shield

The head is at height position during REV.

Head azimuth screw

screw (c)

screw (b)

Phase

KS-FX8R

A Line

B Line

Fixed screw

screw (a)

2.Tape Speed and Wow & Flutter

3.Playback Frequency response

1.Check to see if the reading of the frequency counter & Wow flutter meter is within 2940-3090 Hz( FWD/REV ), and less than 0.35% ( JIS RMS ).

2.In case of out of specification, adjust the motor with a builtin volume resistor.

1.Play the test tape ( VT724 : 1kHz ) back and set the volume position at 2V.

2.Play the test tape ( VT739 )back and confirm 0 + 3dB at1kHz/

8kHz and -4+2dB at 1kHz/125Hz.

3.When 8kHz is out of specification, it will be necessary to read adjust the azimuth.

Built-in volume resistor

Tape Speed 2940-3090Hz Wow&Flutter Less than

0.35% (JIS RMS)

Speaker out 1kHz/8kHz : 0dB_}3dB, 125Hz/1kHz : -4dB+2dB,

1-13

KS-FX8R

Description of major ICs

UPD178018AGC-551 (IC701) : Main system control CPU

1. Pin layout

80 ~ 61

2. Pin function Pin No.

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

21 ~ 40

Port Name I/O Descriptions

KEY 0 KEY 1 KEY 2 LEVEL SM SQ LCDCE LCDDA LCDSCK BUSI/O UNLOCK BUSSI BUSSO BUSSCK NC NC NC NC NC NC GNDPORT VDDPORT AM AFCK MONO FM SEEK/STP NC IFC VDDPLL FMOSC AMOSC GNDPLL AMEO FMEO IC SD/ST STAGE0 NC F/R

O O O

I/O

O O O O O

O O

I I I I I I

Key input 0 Key input 1 Key input 2 Level meter input S.meter level input S.Quality level input CE output to LCD driver Data output to LCD driver Clock output to LCD driver

I/O selector output for J-BUS, H : OUT, L: INPUT Non connect J-BUS Data input J-BUS Data output J-BUS Clock in/output

Non connect Non connect Non connect Non connect Non connect Non connect Port GND Port Vdd Non connect AF check output, L: AF check Monaural on /off selecting output, H:mono on FM/AM switching output L : FM H : AM

Auto seek /stop selecting output, H: Seek, L:Stop I I

Pulse signal input port for Cruise control

FM/AM midle frequency counter input

PLL Vdd

FM/AM limited generator frequency input

None connect

PLL GND

AM error out output

FM error out output

I I

GND

Station detector, Stereo signal input, H:Find Station, L:Stereo

Pull up

Non connect

Main motor output

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