JVC KSFX-490 Service manual

SERVICE MANUAL

CASSETTE RECEIVER

4984520035

KS-FX490

S

Area Suffix

J ------ Northern America

TABLE OF CONTENTS

1 Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD.

No.49845

2003/5

SPECIFICATION

AUDIO AMPLIFIER
SECTION

TUNER SECTION Frequency Range FM 87.5 MHz to 107.9 MHz

CASSETTE DECK
SECTION

GENERAL Power Requirement Operating Voltage DC 14.4 V (11 V to 16 V allowance)

Maximum Power Output Front 50 W per channel

Rear 50 W per channel

Continuous Power Output (RMS) Front 19 W per channel into 4 Ω, 40 Hz to 20 000 Hz at no more

than 0.8 % total harmonic distortion.

Rear 19 W per channel into 4 Ω, 40 Hz to 20 000 Hz at no more

than 0.8 % total harmonic distortion.

Load Impedance 4 Ω (4 Ω to 8 Ω allowance)

Tone Control Range Bass ±10 dB at 100 Hz

Treble ±9 dB at 10 kHz

Frequency Response 40 Hz to 20 000 Hz

Signal-to-Noise Ratio 70 dB

Line-Out Level/Impedance 2.0 V/20 kΩ load (250 nWb/m)

AM 530 kHz to 1 710 kHz

[FM Tuner]

Usable Sensitivity 11.3 dBf (1.0 µV/75 Ω)
50 dB Quieting Sensitivity 16.3 dBf (1.8 µV/75 Ω)

Alternate Channel Selectivity (400 kHz) 65 dB

Frequency Response 40 Hz to 15 000 Hz

Stereo Separation 35 dB

Capture Ratio 1.5 dB

[AM Tuner]

Sensitivity 20 µV

Selectivity 35 dB

Wow & Flutter 0.11% (WRMS)

Fast-Wind Time

Frequency Response (Dolby B NR OFF) 30 Hz to 16 000 Hz (Normal tape)

Signal-to-Noise Ratio
(Normal tape)

Stereo Separation 40 dB

Grounding System Negative ground

Allowable Operating Temperature 0°C to +40°C (32°F to +104°F)
Dimensions (W × H × D) Installation Size 182 mm x 52 mm x 150 mm (7-3/16" x 2-1/16" x 5-15/16")

(Dolby B NR ON) 65 dB

(Dolby B NR OFF) 56 dB

Panel Size 188 mm x 58 mm x 12 mm (7-7/16" x 2-5/16" x 1/2")

Mass 1.3 kg (2.9 lbs) (excluding accessories)

100 sec. (C-60)

Design and specifications are subject to change without notice.

1-2 (No.49845)

1.1 Safety Precautions

SECTION 1

Precautions

!

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.

(No.49845)1-3

SECTION 2

Disassembly method

2.1 Main body

2.1.1 Removing the front panel assembly
(See Fig.1)

(1) Push the detach button in the lower left part of the front

panel assembly and remove the front panel assembly in
the direction of the arrow.

2.1.2 Removing the bottom cover
(See Fig.2)

• Prior to performing the following procedures, remove the front

panel assembly.
(1) Turn the main body upside down.
(2) Insert a screwdriver under the joints to release the two

joints a on the left side, two joints b on the right side and
joint c on the back side of the main body, then remove the
bottom cover from the main body.

CAUTION:

When releasing the joints using a screwdriver, do not damage
the main board.

Front panel assembly

Detach button

Fig.1

Bottom cover

Joint b

Joint a

2.1.3 Removing the front chassis assembly
(See Figs.3 and 4)

• Prior to performing the following procedures, remove the front

panel assembly and bottom cover.
(1) Remove the two screws A on the both sides of the main

body. (See Fig.3.)

(2) Remove the two screws B on the front side of the main

body. (See Fig.4.)

(1) Release the two joints d and two joints e on the both sides

of the main body, then remove the front chassis assembly
toward the front. (See Fig.3.)

Joint d

A

Joint d

Front chassis assembly

A

Fig.3

Joint e

Joint e

Joint a

Joint b

Joint c

Fig.2

Front chassis assembly

B

Fig.4

1-4 (No.49845)

2.1.4 Removing the heat sink

(See Fig.5)

• Prior to performing the following procedure, remove the front

panel assembly.
(1) Remove the two screws C and screw D attaching the heat

sink on the left side of the main body, and remove the heat
sink.

C

D

2.1.5 Removing the rear panel

(See Fig.6)

• Prior to performing the following procedure, remove the front

panel assembly and bottom cover.
(1) Remove the two screws E, three screws F and three

screws G attaching the rear panel on the back side of the
main body.

2.1.6 Removing the main board

(See Fig.7)

• Prior to performing the following procedures, remove the front

panel assembly, bottom cover, front chassis assembly, heat
sink and rear panel.
(1) Remove the two screws H attaching the main board on the

top chassis.

(2) Disconnect the connector CP401 on the main board from

the cassette mechanism assembly.

Heat sink

Fig.5

FG

Rear bracket

EE

Fig.6

Main board

H

C

F

H

CP401

Fig.7

(No.49845)1-5

2.1.7 Removing the cassette mechanism assembly
(See Fig.8)

• Prior to performing the following procedures, remove the front

panel assembly, bottom cover, front chassis assembly, heat
sink, rear panel and main board.
(1) Disconnect the wire from the connector CN402 on the

mecha board.

(2) Disconnect the card wire from the connector CN403 on the

mecha board.

(3) Remove the four screws J attaching the cassette mecha-

nism assembly to the top chassis, take out the cassette
mechanism assembly.

Cassette mechanism assembly

J

J

2.1.8 Removing the mecha board
(See Fig.9)

• Prior to performing the following procedures, remove the front

panel assembly, bottom cover, front chassis assembly, heat
sink, rear panel and main board.
(1) Disconnect the wire from the connector CN402 on the

mecha board.

(2) Disconnect the card wire from the connector CN403 on the

mecha board.
(3) Remove the screw K attaching the mecha board.
(4) Bend the hook f in the direction of the arrow 1 and move

the mecha board in the direction of the arrow 2.
(5) Remove the mecha board from the mecha bracket (L) of

the top chassis.

Mecha board

Top chassis

K

CN402

CN403

CN403

CN402

Fig.8

Mecha board

Fig.9

Top chassis

Hook f

1

2

Mecha bracket (L)

1-6 (No.49845)

2.1.9 Removing the front board
(See Figs.10 to 12)

• Prior to performing the following procedures, remove the front

panel assembly.
(1) Remove the four screws L attaching the rear cover on the

back side of the front panel assembly. (See Fig.10.)

(2) Release the nine joints g, the front panel assembly and

rear cover become separate. (See Fig.11.)

(3) Remove the front board from the front panel assembly.

(See Fig.12.)

Rear cover

L

Joint g

Rear cover

Front board

L

Joints g

L

Fig.10

Front panel assembly

Joint g

Joints g

Fig.11

Front panel assembly

Fig.12

(No.49845)1-7

2.2 Cassette mechanism assembly

r

REFERENCE:

Prior to performing the following procedures, turn the mode
gear on the bottom of the body until the respective part comes
to the EJECT position (Refer to Fig.1).

2.2.1 Removing the cassette guide
(See Fig.2)

(1) Turn the mode gear to set to RVS play or subsequent

mode.

(2) Remove the cassette guide from the main chassis while re-

leasing each two joint tabs a in the direction of the arrow.

Mode gea

Fig.1

Cassette guide

2.2.2 Removing the load arm
(See Fig.3)

(1) Remove the E-washer attaching the load arm.
(2) Move the load arm in the direction of the arrow and release

the joint b on the cassette catch.

Load arm

E-washer

Tab a

Tab a

Fig.2

Joint b

Fig.3

1-8 (No.49845)

2.2.3 Removing the cassette hanger assembly / cassette holder

r

(See Fig.4 to 7)

(1) Check the mode is set to EJECT. Push down the front part

of the cassette holder and move in the direction of the ar­row to release the joint c.

(2) Move the rear part of the cassette hanger assembly in the

direction of the arrow to release it from the two joint bosses
d.

(3) Release the holder stabilizer spring from the hooks e and

f, then pull out from the cassette hanger assembly.

(4) Bring up the rear side of the cassette hanger assembly to

release the joint g and h.

(5) Pull out the cassette catch from the cassette hanger as-

sembly.

Cassette holder assembly

Side bracket

Joints c

Cassette holder assembly

Fig.4

Boss d

Cassette hanger
assembly

Boss d

Cassette stabilizer spring

Hook e

Cassette holder
assembly

Hook g

Cassette hange

assembly

Hook f

Fig.5

Cassette hanger
assembly

Hook h

Fig.6

Cassette hanger assembly

Cassette catch

Cassette holder assembly

Fig.7

(No.49845)1-9

2.2.4 Removing the side bracket assembly
(See Fig.8 to 10)

(1) Remove the screw A attaching the side bracket assembly.
(2) Detach the front side of the side bracket assembly upward

and pull out forward to release the joint i and j in the rear.

CAUTION:

When reassembling, make sure that the boss k of the
main chassis is set in the notch of the load rack under the
side bracket assembly. Do not reattach the load rack on
the boss k.

CAUTION:

After reattaching the side bracket assembly, confirm op­eration.

Side bracket assembly

Joint i

Joint j

A

Side bracket assembly

Fig.8

Side bracket assembly

Joint i

Joint j

Load rack

Load rack

Boss k

Fig.9

Boss k

1-10 (No.49845)

Fig.10

2.2.5 Removing the pinch arm (F) assembly

r

(See Fig.11 and 12)

(1) Remove the polywasher and pull out the pinch arm (F) as-

sembly.

(2) Remove the compulsion spring.

2.2.6 Removing the pinch arm (R) assembly

(See Fig.11 and 12)

(1) Remove the polywasher and pull out the pinch arm (R) as-

sembly.

2.2.7 Removing the slide chassis assembly

(See Fig.13 and 14)

REFERENCE:

It is not necessary to remove the head and the tape guide.
(1) Move the slide chassis assembly in the direction of the ar-

row to release the two joints l and remove from the main
chassis.

(2) Remove the rack link.

CAUTION:

When reassembling, first reattach the rack link, and next
fit the boss m and hook n of the slide chassis assembly
to the hole of the main chassis, and engage the two joints
l.

Joint l

Joint l

Slide chassis assembly

Fig.13

Head

Tape guide

Boss m

Rack link

Hook n

Polywasher

Polywasher

Compulsion
spring

Pinch arm
(R) assembly

Pinch arm
(F) assembly

Fig.11

Pinch arm (F) assembly

Pinch arm
(R) assembly

Polywashe

Fig.14

Polywasher

Fig.12

(No.49845)1-11

2.2.8 Removing the head / tape guide
(See Fig.16 and 17)

REFERENCE:

It is not necessary to remove the slide chassis assembly.
(1) Remove the band attaching the wire to the head.
(2) Remove the two screws B, the head and the head support

spring.
(3) Remove the pinch arm spring from the tape guide.
(4) Remove the tape guide and the pinch spring arm.

CAUTION:

When reattaching the pinch arm spring, set both end of
it to the pinch spring arm (remarked o).

CAUTION:

When reattaching the head, set the wires into the groove
of the tape guide (Fig.16).

2.2.9 Removing the flywheel assembly (F) & (R)
(See Fig.18 and 19)

REFERENCE:

It is not necessary to remove the slide chassis assembly.
(1) Remove the belt at the bottom.
(2) Remove the two polywashers on the upper side.
(3) Pull out each flywheel assembly downward.

B

Slide chassis assembly

Flywheel assembly (F)

Flywheel assembly (R)

Belt

Fig.17

Polywasher

Polywasher

Head

Head support spring

Tape guide

o

Pinch spring arm

Head

Fig.15

Tape guide

B

Pinch arm spring

Flywheel assembly (F)

Flywheel assembly (R)

Fig.18

o

1-12 (No.49845)

Slid chassis assembly

Fig.16

2.2.10 Disassembling the flywheel assembly (F)

r

(See Fig.19 and 20)

(1) Push and turn counterclockwise the spring holder (F) to re-

lease the three joints p on the bottom of the flywheel.

(2) The spring holder (F), the TU spring and the friction gear

play come off.

(3) Remove the polywasher and felt.

2.2.11 Disassembling the flywheel assembly (R)

(See Fig.19 and 20)

(1) Push and turn clockwise the spring holder (R) to release

the three joints q on the bottom of the flywheel.

(2) The spring holder (R), the FF spring and the friction gear

FF come off.

(3) Remove the polywasher and the felt.

2.2.12 Removing the reel board

(See Fig.21 and 22)

(1) Remove the two screws C attaching the reel board.
(2) Move the reel board in the direction of the arrow to release

the joint r.

(3) Unsolder the wires if necessary.

CAUTION:

When reattaching, confirm operation of the MODE
switch and the ST-BY switch.
The mode position between EJECT and ST-BY is opti­mum for reattaching.
Connect the card wire extending from the reel board to
the FFC pad before reattaching the reel board.

FFC pad

C

Joint

Reel board

C

Fig.21

FFC pad

CT-1 switch

MODE switch

Flywheel
assembly (F)

Joint p

Joints p

Fig.19

Polywasher

Spring holder (R)

Spring holder (F)

TU spring

Friction gear FF

Friction gear play

Polywasher

FF spring

Flywheel
assembly (R)

Joints q

Joint q

Soldering

ST-BY switch

Fig.22

Felt

Flywheel assembly (F)

Fig.20

Felt

Flywheel assembly (R)

(No.49845)1-13

2.2.13 Removing the gear base arm / gear base link assembly
(See Fig.23 to 25)

(1) Move the gear base arm in the direction of the arrow.
(2) Insert a slotted screwdriver to the gear base spring under

the gear base arm, and release the gear base arm upward
from the boss on the gear base assembly.

(3) Remove the gear base arm from the main chassis while re-

leasing the two joints s.

(4) Move the gear base link assemby in the direction of the ar-

row to release the two joints t.

REFERENCE:

When reattaching the gear base arm, make sure that the
boss on the gear base assembly is inside the gear base
spring.

2.2.14 Removing the FFC pad
(See Fig.25 and 27)

(1) Push each joint hook u of the FFC pad and remove toward

the bottom.

Gear base
link assembly

Gear base spring

Joint t

Gear base arm

Joints s

Hook u

FFC pad

Hook u

Joint t

Fig.23

Gear base arm

Gear base link
assembly

Screwdriver

Fig.24

Gear base arm

1-14 (No.49845)

FFC pad

Fig.25

2.2.15 Removing the mode gear

r

r

(See Fig.26 and 29)

(1) Remove the polywasher on the bottom and pull out the

mode gear.

2.2.16 Removing the mode switch actuator

(See Fig.26, 27 and 29)

(1) Pull out the mode switch actuator at the bottom.

REFERENCE:

When reattaching the mode switch actuator to the main
chassis, make sure to set on the shaft and insert v into
the slot w.

2.2.17 Removing the direction link / direction plate

(See Fig.27 to 29)

(1) Remove the polywasher attaching the direction link.
(2) Bring up the direction link to release the three joints x, y

and z at a time.

(3) Move the direction plate in the direction of the arrow to re-

lease the two joints a’.

REFERENCE:

When reattaching the direction plate, engage the two
joints a’ and move in the direction of the arrow (Refer to
Fig.28).

REFERENCE:

When reattaching the direction link, move the direction
plate in the direction of the arrow and engage the three
joint x, y and z at a time (Refer to Fig.29).

2.2.18 Removing the mode rack assembly

(See Fig.27 and 28)

(1) Move the mode rack assembly in the direction of the arrow

to release the two joints b’ and the joint c’.

REFERENCE:

When reattaching, set the two b’ on the bottom of the
mode rack assembly into the slots of the main chassis
and move in the direction of the arrow (See Fig.28).

Direction plate

Direction plate

Joints a'

Joint z

Direction link

Direction plate

Mode switch actuator

Direction link

Fig.26

Slot w

Joint y

Polywasher

Fig.27

Mode rack assembly

Joint b'

Mode gear

Polywashe

Mode rack assembly

Joint x

Joint b'

Joint c'

Joints a'

Fig.28

Direction link

Mode switch actuator

Polywasher

v

Mode gea

Direction plate

Mode rack assembly

Fig.29

(No.49845)1-15

2.2.19 Removing the gear base assembly / take up gear / reflector gear

r

(See Fig.30 to 32)

(1) Push in the pin d’ of the gear base assembly on the upper

side of the body and move the reflector gear toward the
bottom, then pull out.

(2) Remove the polywasher on the bottom and pull out the

take up gear.

(3) Move the gear base assembly in the direction of the arrow

to release it from the two slots e’ of the main chassis.

REFERENCE:

The parts are damaged when removed. Please replace
with new ones.

2.2.20 Removing the reel driver / reel spindle
(See Fig.32)

(1) Draw out the reel driver from the shaft on the main chassis

and remove the reel driver spring and the reel spindle re­spectively.

CAUTION:

The reel driver is damaged when removed. Please re­place with a new one.

Gear base assembly

Pin d'

Polywasher

Slot e'

Slot e'

Fig.30

Take up gear

Reflector gear

Reel driver

Reel driver spring

Reel spindle

Main chassis

Reflector gear

Fig.31

Reel driver

Reel driver spring

Reel spindle

Gear base assembly

Slots e’

Take up gea

Polywasher

Fig.32

1-16 (No.49845)

2.2.21 Removing the side bracket assembly

(See Fig.33 to 37)

(1) Remove the eject cam plate spring.
(2) Push the joint f’ through the slot to remove the load rack

downward.

(3) Move the eject cam limiter in the direction of the arrow to

release it from the boss g’ of the side bracket assembly and
from the two joints h’.

(4) Move the eject cam plate in the direction of the arrow to re-

lease the joint i’.

CAUTION:

When reassembling, confirm operation of each part be­fore reattaching the eject cam plate spring.

Joint f'

Side bracket assembly

Boss g'

Eject cam plate

Fig.36

Side bracket assembly

Joint i'

Eject cam plate spring

Side bracket assembly

Joint h'

Side bracket
assembly

Boss g'

Boss g'

Load rack

Fig.33

Eject cam limiter

Joint f'

Fig.34

Eject cam limiter

Eject cam plate

Joint i'

Fig.37

Joint h'

Load rack

Joint h'

Eject cam plate

Fig.35

Joint h'

(No.49845)1-17

2.2.22 Removing the main motor assembly / sub motor assembly

r

r

r

(See Fig.38 to 40)

(1) Remove the belt at the bottom.
(2) Remove the polywasher and pull out the mode gear.
(3) Pull out the reduction gear (B).
(4) Remove the polywasher and pull out the reduction gear

(A).

(5) Remove the two screws attaching the main motor assem-

bly.

(6) Remove the two screws E attaching the sub motor assem-

bly.

(7) Unsolder the wires on the reel board if necessary.

CAUTION:

When reassembling, adjust the length of the wires ex­tending from the sub motor asswmbly by attaching them
to the side of the sub motor assembly with the wires ex­tending from the main motor assembly using a spacer.

Belt

Reduction gear (B)

Reduction gear (B)

E

Mode gear

Polywasher

Fig.38

Main motor

D

assembly

Reduction
gear (A)

Polywashe

Sub moto
assembly

E

Polywasher

Reduction gear (A)

D

Spacer

Main motor assembly

Sub motor assembly

Fig.39

Main motor assembly

Sub motor assembly

Fig.40

Space

1-18 (No.49845)