JVC KSFX-621 Service manual
49825200303
KS-FX621
SERVICE MANUAL
CASSETTE RECEIVER
KS-FX621
11
RPT
1097
12
8
MO
RND
S
C
M
MODE
Area Suffix
U ------ Other Areas
TABLE OF CONTENTS
1 Safety precaution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
4 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD.
No.49825
2003/03
KS-FX621
SECTION 1
Safety precaution
CAUTION
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.
1-2 (No.49825)
SECTION 2
Disassembly method
2.1 Main body
2.1.1 Removing the front panel assembly
(See Fig.1)
(1) Press the release button and remove the front panel as-
sembly.
2.1.2 Removing the bottom cover
(See Fig.2)
• Prior to performing the following procedure, remove the front
panel assembly.
(1) Turn the body upside down.
(2) Insert a screwdriver under the joints to release the two
joints a on the left si de, the two joints b on the right side and
the joint c on the back of the body, then remove the bottom
cover from the body.
CAUTION:
When releasing the joint c using a screwdriver, do not damage
the main board.
Front panel assembly
Joint a
Fig.1
Bottom cover
KS-FX621
Release button
Joint
b
2.1.3 Removing the front chassis
(See Fig.3)
• Prior to performing the following procedure, remove the front
panel assembly and bottom cover.
(1) Remove the screw A on each side of the body.
(2) Release the two joints d and the two joints e on the sides,
then remove the front chassis toward the front.
Joint a
Joint c
Fig.2
Joint d
Joint e
A
Joint d Joint e
Front chassis
Fig.3
Joint b
(No.49825)1-3
KS-FX621
2.1.4 Removing the heat sink
(See Fig.4)
• Prior to performing the following procedure, remove the front
panel assembly.
(1) Remove the two scre ws B and two screws C attaching the
heat sink on the left side of the body, and remove the heat
sink.
2.1.5 Removing the rear panel
(See Fig.5)
• Prior to performing the following procedure, remove the front
panel assembly and bottom cover.
(1) Remove the two screws D, three screws E and three
screws F attaching the rear panel on the back of the body.
CB C
Heat sink
Fig.4
2.1.6 Removing the main board
(See Fig.6)
• Prior to performing the following procedure, remove the front
panel assembly, bottom cover, front chassis, heat sink and
rear panel.
(1) Remove the two screws G attaching the main board on the
top chassis.
(2) Disconnect the connectors CP701 on the main board from
the cassette mechanism assembly.
E
G
D
Rear panel
EFF
D
Fig.5
Main board assembly
G
1-4 (No.49825)
CP701
Fig.6
2.1.7 Removing the cassette mechanism assembly
(See Fig.7)
• Prior to performing the following procedure, remove the front
panel assembly, bottom cover, front chassis, heat sink, rear
panel and main board.
(1) Remove the four screws H attaching the cassette mecha-
nism assembly from the top chassis.
2.1.8 Removing the mecha bo ar d
(See Fig.8)
• Prior to performing the following procedure, remove the front
panel assembly, bottom cover, front chassis, heat sink, rear
panel, main board and cassette mechanism assembly.
(1) Disconnect the wire from the connectors CN402 and
CN403 on the mecha board.
(2) Remove the screw J attaching the mecha board.
KS-FX621
Cassette mechanism assembly
H
H
H H
Top chassis
Fig.7
CN402
J
2.1.9 Removing the front board
(See Figs.9 to 11)
• Prior to performing the following procedure, remove the front
panel assembly.
(1) Remove the four screws L attaching the rear cover on the
back of the front panel assembly. (See fig.9)
(2) Release the eleven joints f, the front panel and the rear
cover become separate. (See fig.10)
(3) Remove the front board from the front panel assembly.
(See fig.11)
K
K
K K
Fig.9
CN401
Front panel assembly
Joint h
LCD & Key control board
Fig.8
Joint h
Joint h
Fig.10
CN403
Joint h
Rear cover
Fig.11
(No.49825)1-5
KS-FX621
r
2.2 CD 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).
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 casse tte 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
1-6 (No.49825)
2.2.3 Removing the cassette hanger assembly / cassette holder
y
(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 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
KS-FX621
Cassette hanger assembly
Cassette stabilizer spring
Hook f
Hook e
Fig.5
Side bracket
Joints c
Cassette holder assembly
Fig.4
Boss d
Cassette hanger
assembly
Boss d
assette holder
ssembly
Cassette hanger assembl
Hook g
Hook h
Fig.6
Cassette hanger assembly
Cassette catch
Cassette holder assembly
Fig.7
(No.49825)1-7
KS-FX621
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
Side bracket assembly
Joint i
Joint j
Load rack
A
Joint j
Boss k
Fig.9
Side bracket assembly
Fig.8
Boss k
Load rack
1-8 (No.49825)
Fig.10
2.2.5 Removing the pinch arm (F) assembly
r
r
(See Fig.11 and 12)
(1) Remove the polywasher and pull out the pinch arm (F) as-
sembly.
(2) Remove the compulsion spring.
KS-FX621
Pinch arm (F) assembly
Polywasher
Compulsion spring
Polywasher
Pinch arm
(R) assembly
2.2.6 Removing the pinch arm (R) assembly
(See Fig.11 and 13)
(1) Remove the polywasher and pull out the pinch arm (R) as-
sembly.
Pinch arm
(R) assembly
Pinch arm
(F) assembly
Fig.11
Polywashe
Polywashe
Fig.12
Joint l
Joint l
Slide chassis
assembly
Fig.14
Fig.13
2.2.7 Removing the slide chassis assembly
(See Fig.14 and 15)
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.
Head
Tape guide
Boss m
Rack link
Hook
n
Fig.15
(No.49825)1-9
KS-FX621
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).
Slide chassis assembly
B
Pinch arm spring
Head
Head support spring
Tape guide
o
B
Pinch spring arm
o
Head
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.
Flywheel assembly (F)
Tape guide
Belt
Slid chassis assembly
Fig.17
Polywasher
Polywasher
Flywheel assembly (F)
Flywheel assembly (R)
1-10 (No.49825)
Flywheel assembly (R)
Fig.19
Fig.18
2.2.10 Disassembling the flywheel assembly (F )
r
(See Fig.20 and 21)
(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.
KS-FX621
Polywasher
Spring holder (F)
TU spring
Flywheel assembly (F)
Joints p
Joint p
Fig.20
2.2.11 Disassembling the flywheel assembly (R)
(See Fig.20 and 22)
(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.
Polywasher
Spring holder (R)
FF spring
Flywheel assembly (R)
Joints q
Joint q
Friction gear play
Felt
Flywheel assembly (F)
Fig.21
FFC pad
C
Joint
Friction gear FF
Felt
Flywheel assembly (R)
Fig.22
2.2.12 Removing the reel board
(See Fig.23 and 24)
(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.
C
Reel board
Fig.23
FFC pad
CT-1 switch
MODE switch
ST-BY switch
Soldering
Fig.24
(No.49825)1-11
KS-FX621
2.2.13 Removing the gear base arm / gear base link assembly
(See Fig.25 to 27)
(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.
Joint t
Gear base arm
Joints s
Hook u
FFC pad
Hook u
2.2.14 Removing the FFC pad
(See Fig.27 and 29)
(1) Push each joint hook u of the FFC pad and remove toward
the bottom.
Gear base
link assembly
Joint t
Gear base spring
Gear base link assembly
Fig.25
Gear base arm
Screwdriver
Fig.26
Gear base arm
1-12 (No.49825)
FFC pad
Fig.27
KS-FX621
r
r
2.2.15 Removing the mode gear
(See Fig.28 and 31)
(1) Remove the polywasher on the bottom and pull out the
mode gear.
2.2.16 Removing the mode switch actuator
(See Fig.28, 29 and 31)
(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.29 to 31)
(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.30).
REFERENCE:
When reattaching the direction link, move the direction plate in
the direction of the arrow and engage the three join t x, y and
z at a time (Refer to Fig.31).
2.2.18 Removing the mode rack assembly
(See Fig.29 and 30)
(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' Eon the bottom of the mode
rack assembly into the slots of the main chassis and move in
the direction of the arrow (See Fig.30).
Mode switch actuator
Direction plate
Direction plate
Direction link
Fig.28
Slot w
Mode rack assembly
Joints a'
Joint z
Direction link
Polywasher
Joint y
Fig.29
Joint x
Direction plate Mode rack assembly
Joint b'
Mode gear
Polywashe
Joint b'
Joint c'
Joints a'
Fig.30
Direction link
Mode switch actuator
Polywasher
v
Mode gea
Direction plate
Mode rack assembly
Fig.31
(No.49825)1-13
KS-FX621
2.2.19 Removing the gear base assembly / take up gear / reflector gear
(See Fig.32 to 34)
(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.
Slot e'
Gear base assembly
Pin d'
Slot e'
Fig.32
2.2.20 Removing the reel driver / reel spindle
(See Fig.34)
(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.
Polywasher
Reflector gear
Reel driver
Reel driver spring
Reel spindle
Take up gear
Fig.33
Reel driver
Reel driver spring
Reel spindle
Gear base assembly
1-14 (No.49825)
Main chassis
Reflector gear
Slots e
Take up gear
Polywasher
Fig.34
2.2.21 Removing the side bracket assembl y
(See Fig.35 to 39)
(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 brack et 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 limiter
Joint h'
Eject cam plate
Fig.37
Side bracket assembly
Boss g'
KS-FX621
Joint h'
Eject cam plate spring
Side bracket assembly
Boss g'
Joint h'
Fig.35
Eject cam limiter
Joint f'
Load rack
Joint h'
Eject cam plate
Eject cam plate
Joint i'
Fig.38
Side bracket assembly
Joint i’
Fig.39
Fig.36
Load rack
(No.49825)1-15
KS-FX621
r
2.2.22 Removing the main motor assembly / sub motor assembly
(See Fig.40 to 42)
(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 D attaching the main motor as-
sembly.
(6) Remove the two scre ws 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)
Mode gear
Polywasher
Fig.40
Polywasher
D
E
Main motor
assembly
Reduction
gear (A)
Polywashe
Sub motor
assembly
E
Spacer
Main motor assembly
Reduction gear (A)
D
Main motor assembly
Sub motor assembly
Fig.41
1-16 (No.49825)
Sub motor assembly
Fig.42
Spacer
SECTION 3
Adjustment
3.1 Adjustment method
Test instruments reqired for adjustment Standard volume position
1. Digital oscilloscoe(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)
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.pilot 7.5kHz dev
Output level 0dB (1 V,50 /open terminal)
KS-FX621
Power supply voltage.............. DC14.4V(11V to 16V allowance)
Load impedance............ 4 (4 to 8 allowance)
Line out level/Impedance..............1.0V/20k load (250 nWb/m)
Frequency band
Band
FM
AM
87.5 MHz to 108.0MHz
522 kHz to 1620 kHz
MW
LW
144 kHz to 279 kHz
(No.49825)1-17
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