JVC KSFX-921 Service manual
SERVICE MANUAL
CASSETTE RECEIVER
4984620036
KS-FX921
SOUND
ATT
U
SOURCE
F
R
D
VOL
VOL
Area Suffix
U --------------------- Other Areas
TABLE OF CONTENTS
1 Precaution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
4 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LIMITED
No.49846
2003/5
SPECIFICATION
AUDIO AMPLIFIER
SECTION
TUNER SECTION Frequency Range FM 87.5 MHz to 108.0 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 7 0 dB
Line-Out Level/Impedance 2.0 V/20 kΩ load (250 nWb/m)
AM 531 kHz to 1 602 kHz
[FM Tuner] Usable Sensitivity 11.3 dBf (1.0 ΩV/75 Ω)
50 dB Quieting Sensitivity 16.3 dBf (1.8 ΩV/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 ΩV
Selectivity 35 dB
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 56 dB (Normal tape)
(Dolby B NR ON) 65 dB
(Dolby B NR OFF) 56 dB
Stereo Separation 40 dB
Grounding System Negative ground
Allowable Operating Temperature 0ºC to +40ºC
Dimensions (W × H × D) Installation Size (approx.) 182 mm ×52 mm ×150 mm
Panel Size (approx.) 188 mm × 58 mm × 12 mm
Mass (approx.) 1.5 kg (excluding accessories)
Design and specifications are subject to change without notice.
1-2 (No.49846)
1.1 Safety Precautions
SECTION 1
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.
(No.49846)1-3
SECTION 2
Front chassis assembly
Disassembly method
2.1 Main body
2.1.1 Removing the front panel assembly
(See Fig.1)
(1) Press the rele ase button and remove the front panel as-
sembly.
2.1.2 Removing the bottom cover
(See Fig.2)
• Prior to performing the following procedures, remove the fro nt
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
Release 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 fro nt
panel assembly and bottom cover.
(1) Remo ve the two screws A on the both sides of the main
body. (See Fig.3.)
(2) Remove th e two screws B on the front side of the main
body. (See Fig.4.)
(3) 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 a
Joint d
Joint d
B
Joint c
Fig.2
A
Front chassis
Fig.3
Joint b
Joint e
Joint e
1-4 (No.49846)
Fig.4
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
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) Disconn ect the connector CP701 on the main board from
the cassette mechanism assembly.
D
F
Rear bracket
EE
H
Heat sink
Fig.5
G
F
Fig.6
Main board
H
CP701
Fig.7
(No.49846)1-5
2.1.7 Removing the cassette mechanism assembly
(See Fig.8)
• Prior to performing the following procedures, remove the fro nt
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
H
H
2.1.8 Removing the mecha board
(See Fig.9)
• Prior to performing the following procedures, remove the fro nt
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 mech a board from the mecha bracket (L) of
the top chassis.
H H
Top chassis
Fig.8
CN402
J
CN401
Fig.9
Mecha board
CN403
1-6 (No.49846)
2.1.9 Removing the front board
m
(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) Rele ase 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.)
L
t g
ar cover
Front board
L
Joints
L
Rear cover
Fig.10
g
Joints g
Fig.11
Front panel assembly
Front panel asse
Joint g
Fig.12
(No.49846)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.49846)
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 directi on of the arrow to release the joint c.
(2) Move th e 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 h ooks e and
f, then pull out from the cassette hanger assembly.
(4) Bri ng up the rear side of the cassette hanger assembly to
release the joint g and h.
(5) Pull ou t 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.49846)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.49846)
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 compul sion 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 th e slid e chassis assembly in the di recti on 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.49846)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) Remov e 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.49846)
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 pol ywasher and felt.
2.2.11 Disassembling the flywheel assembly (R)
(See Fig.19 and 20)
(1) Push an d 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 pol ywasher and the felt.
2.2.12 Removing the reel board
(See Fig.21 and 22)
(1) Remove the tw o screws C attaching the reel board.
(2) Move the reel board in the direction of the arrow to release
the joint r.
(3) Unsol der 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.49846)1-13
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