JVC KS-FX490 - Radio / Cassette Player User manual

SERVICE MANUAL
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD. No.49845
2003/5
CASSETTE RECEIVER
4984520035KS-FX490
TABLE OF CONTENTS
1 Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
S
Area Suffix
J ------ Northern America

1-2 (No.49845)
SPECIFICATION
Design and specifications are subject to change without notice.
AUDIO AMPLIFIER
SECTION
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 Ωto 8 Ωallowance)
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 kΩload (250 nWb/m)
TUNER SECTION Frequency Range FM 87.5 MHz to 107.9 MHz
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
CASSETTE DECK
SECTION
Wow & Flutter 0.11% (WRMS)
Fast-Wind Time
100 sec. (C-60)
Frequency Response (Dolby B NR OFF) 30 Hz to 16 000 Hz (Normal tape)
Signal-to-Noise Ratio
(Normal tape)
(Dolby B NR ON) 65 dB
(Dolby B NR OFF) 56 dB
Stereo Separation 40 dB
GENERAL Power Requirement Operating Voltage DC 14.4 V (11 V to 16 V allowance)
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")
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)

(No.49845)1-3
SECTION 1
Precautions
1.1 Safety 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.

1-4 (No.49845)
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.
Fig.1
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 aon the left side, two joints bon the right side and
joint con 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.
Fig.2
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 Aon the both sides of the main
body. (See Fig.3.)
(2) Remove the two screws Bon the front side of the main
body. (See Fig.4.)
(1) Release the two joints dand two joints eon the both sides
of the main body, then remove the front chassis assembly
toward the front. (See Fig.3.)
Fig.3
Fig.4
Front panel assembly
Detach button
Bottom cover
Joint a
Joint b
Joint a
Joint b
Joint c
Joint d
Joint d
Front chassis assembly
A
Joint e
Joint e
A
B
Front chassis assembly

(No.49845)1-5
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 Cand screw Dattaching the heat
sink on the left side of the main body, and remove the heat
sink.
Fig.5
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 Fand three
screws Gattaching the rear panel on the back side of the
main body.
Fig.6
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 Hattaching the main board on the
top chassis.
(2) Disconnect the connector CP401 on the main board from
the cassette mechanism assembly.
Fig.7
C
D
Heat sink
C
FG
EE
F
Rear bracket
H
Main board
CP401
H

1-6 (No.49845)
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 Jattaching the cassette mecha-
nism assembly to the top chassis, take out the cassette
mechanism assembly.
Fig.8
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 Kattaching the mecha board.
(4) Bend the hook fin 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. Fig.9
JJ
Top chassis
Cassette mechanism assembly
CN403 CN402
Mecha board
K
Mecha board Hook f
Top chassis
Mecha bracket (L)
CN402
CN403
1
2

(No.49845)1-7
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 Lattaching 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.)
Fig.10
Fig.11
Fig.12
L
L
L
Rear cover
Joints g
Joints g
Joint g
Joint g
Rear cover
Front panel assembly
Front board Front panel assembly

1-8 (No.49845)
2.2 Cassette mechanism assembly
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).
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 ain the direction of the arrow.
Fig.2
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 bon the cassette catch.
Fig.3
Mode gea
r
Cassette guide
Tab a
Tab a
Load arm
E-washer
Joint b

(No.49845)1-9
2.2.3 Removing the cassette hanger assembly / cassette holder
(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 ar-
row 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 eand
f, then pull out from the cassette hanger assembly.
(4) Bring up the rear side of the cassette hanger assembly to
release the joint gand h.
(5) Pull out the cassette catch from the cassette hanger as-
sembly.
Fig.4
Fig.5
Fig.6
Fig.7
Cassette holder assembly
Side bracket
Joints c
Cassette holder assembly
Cassette hanger
assembly
Boss d
Boss d
Cassette hange
r
assembly
Cassette stabilizer spring
Hook f
Hook e
Cassette hanger
assembly
Hook h
Hook g
Cassette holder
assembly
Cassette holder assembly
Cassette hanger assembly
Cassette catch

1-10 (No.49845)
2.2.4 Removing the side bracket assembly
(See Fig.8 to 10)
(1) Remove the screw Aattaching the side bracket assembly.
(2) Detach the front side of the side bracket assembly upward
and pull out forward to release the joint iand jin the rear.
CAUTION:
When reassembling, make sure that the boss kof 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 op-
eration.
Fig.8
Fig.9
Fig.10
A
Side bracket assembly
Side bracket assembly
Joint i
Joint j
Joint i
Joint j
Side bracket assembly
Boss k
Load rack
Boss k
Load rack