JVC KSFX-925-R Service manual

SERVICE MANUAL

CASSETTE RECEIVER

KS-FX925R

SOUND

ATT

KS-FX925R

U

SOURCE

R

D

VOL

Contents

F

VOL

EQ

Safety precaution
Disassembly method
Adjustment method
Description of major ICs

DAB

TAP

E

Area Suffix

EE --------- Russian Federation

1- 2
1- 3
1-11
1-15~26

COPYRIGHT 2002 VICTOR COMPANY OF JAPAN, LTD.

No.49742

May. 2002

KS-FX925R

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.

1-2

Disassembly method

Removing the front panel unit

(See Fig.1)

1.

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

KS-FX925R

Front panel unit

Removing the bottom cover

(See Fig.2,3)

1.

Turn the body upside down.

2.

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

CAUTION:

When disengaging the joint c using a
screwdriver, do not damage or break the
board.

Removing the front chassis (See Fig.4,5)

Prior to performing the following procedure, remove
the bottom cover.

1.

Remove the two screws A attaching the front
chassis.

Fig.1

Joint a

Bottom cover

Joint c

Joint b

Fig. 2

Joint b

Bottom cover

2.

Remove the two screws B on each side of the body.

3.

Release the two joints d and the two joints e on the
sides. remove the front chassis toward the front.

Joint d

Joint d

B

Front chassis

Fig. 5

Joint e

Joint e

Joint a

A

Joint c

Fig. 3

Front chassis

Fig.4

1-3

KS-FX925R

Removing the heat sink (See Fig.6)

1.

Remove the four screws C attaching the heat sink
on the left side of the body, and remove the heat
sink.

Removing the rear panel (See Fig.7 )

C

C

Heat sink

Fig. 6

C

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

1.

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

D

Rear panel

CP401

Removing the main amplifier board assembly

(See Fig.8)

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

E

D

D

Fig. 7

1.

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

2.

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

1-4

F

Main board assembly

F

Fig. 8

Removing the cassette mechanism assembly

(See Fig.9)

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

1.

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

Cassette mechanism assembly

G

KS-FX925R

G

Removing the (LCD & key) control switch

board (See Fig.10

Prior to performing the following procedure, remove
the front panel assembly.

1.

Remove the four screws H attaching the rear cover
on the back of the front panel assembly.

2.

Unjoint the nine joints f with the front panel and the
rear cover.

3.

Remove the control switch board on the back of the
front panel.

to 12)

Front panel

H

H

G

Joint f

G

Top cover

Fig. 9

H

H

Fig. 10

Rear cover

Joint f

Joint f

LCD & Key control board

Joint f

Fig. 11

Fig. 12

1-5

KS-FX925R

<Cassette mechanism section>

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).

Removing the reinforce bracket

(See Fig.1 and 2)

1.

Remove the screw A attaching the reinforce bracket
on the bottom of the body.

2.

To release joint a, turn and detach the reinforce
bracket from the side bracket assembly as shown in
Fig.2

Removing the cassette guide (See Fig.3)

1.

Turn the mode gear to set to RVS play or
subsequent mode.

2.

Remove the cassette guide from the main chassis
while releasing each two joint tabs b in the direction
of the arrow.

Mode gear

Reinforce bracket

A

Fig.1

Joint a

Reinforce bracket

Removing the head board (See Fig.4)

1.

Remove the screw B on the upper side. Unsolder
the wires on the under side of the head board, if
necessary.

REFERENCE:

Cassette guide

When reassembling, twist the wires by
turning the head board twice remarked c
and pass through the notch d as shown
in Fig.4.

Head board

B

Fig.2

Head board

Soldering

notch d

1-6

Tab b

Tab b

c

Fig.4Fig.3

KS-FX925R

y

Removing the load arm (See Fig.5)

1.

Remove the E-washer attaching the load arm.

2.

Move the load arm in the direction of the arrow and
release the joint e on the cassette catch.

Removing the cassette hanger assembly /
cassette holder (See Fig.6 to 9)

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 f.

2.

Move the rear part of the cassette hanger assembly
in the direction of the arrow to release it from the two
joint bosses g.

Load arm

E-washer

Cassette holder assembly

Side bracket

Joints f

Joint e

Fig.5

Boss g

Cassette hanger
assembly

Boss g

3.

Release the holder stabilizer spring from the hooks h
and i, then pull out from the cassette hanger
assembly.

4.

Bring up the rear side of the cassette hanger
assembly to release the joint j and k.

5.

Pull out the cassette catch from the cassette hanger
assembly.

Cassette holder
assembly

Cassette holder assembly

Fig.6

Cassette hanger assembl

Cassette stabilizer spring

Hook i

Hook h

Fig.7

Cassette hanger assembly

Cassette catch

Cassette holder assembly

Hook j

Fig.8

Cassette hanger assembly

Hook k

Fig.9

1-7

KS-FX925R

Removing the side bracket assembly

(See Fig.10 to 12)

1.

Remove the screw C attaching the side bracket
assembly.

2.

Detach the front side of the side bracket assembly
upward and pull out forward to release the joint l and
m in the rear.

CAUTION:

CAUTION:

When reassembling, make sure that the
boss n 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 n.

After reattaching the side bracket
assembly, confirm operation.

Side bracket assembly

Joint l

Joint m

C

Side bracket assembly

Fig.10

Side bracket assembly

Joint l

Joint m

Load rack

Load rack

Boss n

Boss n

Fig.11

1-8

Fig.12

Removing the pinch arm (F) assembly

(See Fig.13 and 14)

1.

Remove the polywasher and pull out the pinch arm
(F) assembly.

2.

Remove the compulsion spring.

Removing the pinch arm (R) assembly

(See Fig.13 and 15)

1.

Remove the polywasher and pull out the pinch arm
(R) assembly.

Removing the slide chassis assembly

(See Fig.16 and 17)

Polywasher

Polywasher

Compulsion spring

Pinch arm
(R) assembly

Fig.13

Pinch arm
(F) assembly

Pinch arm (F) assembly

Polywasher

KS-FX925R

REFERENCE:

It is not necessary to remove the head
and the tape guide.

1.

Move the slide chassis assembly in the direction of
the arrow to release the two joints o and remove
from the main chassis.

2.

Remove the rack link.

CAUTION:

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

Rack link

Fig.14

Boss p

Pinch arm
(R) assembly

Fig.15

Head

Hook q

Polywasher

Tape guide

Joint o

Slide chassis assembly

Fig.16

Joint o

Fig.17

1-9

KS-FX925R

Removing the head / tape guide

(See Fig.18 and 19)

REFERENCE:

1.

Remove the band attaching the wire to the head.

2.

Remove the two screws D, 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:

CAUTION:

It is not necessary to remove the slide
chassis assembly.

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

When reattaching the head, set the wires
into the groove of the tape guide (Fig.18).

D

Slide chassis assembly

Head

Tape guide

Fig.18

D

Pinch arm spring

Head

Head support spring

Tape guide

Removing the flywheel assembly (F) & (R)

(See Fig.20 and 21)

REFERENCE:

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)

It is not necessary to remove the slide
chassis assembly.

Belt

r

Pinch spring arm

r

Slid chassis assembly

Fig.19

Polywasher

Polywasher

Flywheel assembly (R)

1-10

Fig.20

Flywheel assembly (F)

Fig.21

Flywheel assembly (R)

Disassembling the flywheel assembly (F)

(See Fig.22 and 23)

1.

Push and turn counterclockwise the spring holder (F)
to release the three joints s 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.

Flywheel assembly (F)

Joints s

KS-FX925R

Flywheel assembly (R)

Joints t

Disassembling the flywheel assembly (R)

(See Fig.22 and 24)

1.

Push and turn clockwise the spring holder (R) to
release the three joints t 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.

Removing the reel board

(See Fig.25 and 26)

1.

Remove the two screws E attaching the reel board.

2.

Move the reel board in the direction of the arrow to
release the joint u.

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.

Joint s

Fig.22

Polywasher

Polywasher

Spring holder (R)

Spring holder (F)

TU spring

Friction gear FF

Friction gear play

Felt

Flywheel assembly (F)

FF spring

Felt

Flywheel assembly (R)

Fig.23 Fig.24

Joint t

Connect the card wire extending from
the reel board to the FFC pad before
reattaching the reel board.

FFC pad

E

Reel board

E

Fig.25

Joint u

FFC pad

CT-1 switch

MODE switch

Soldering

ST-BY switch

Fig.26

1-11

KS-FX925R

Removing the gear base arm / gear base
link assembly (See Fig.27 to 29)

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 releasing the two joints v.

4.

Move the gear base link assemby in the direction of
the arrow to release the two joints w.

REFERENCE:

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

Removing the FFC pad

(See Fig.27 and 29)

Gear base
link assembly

Gear base spring

Joint w

Gear base arm

Joints v

Hook x

FFC pad

Hook x

Joint w

Fig.27

Gear base arm

Screwdriver

1.

Push each joint hook x of the FFC pad and remove
toward the bottom.

Gear base link assembly

Fig.28

Gear base arm

1-12

FFC pad

Fig.29

KS-FX925R

Removing the mode gear

(See Fig.30 and 33)

1.

Remove the polywasher on the bottom and pull out
the mode gear.

Removing the mode switch actuator

(See Fig.30, 31 and 33)

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 y into the slot z.

Removing the direction link / direction
plate (See Fig.31 to 33)

1.

Remove the polywasher attaching the direction link.

2.

Bring up the direction link to release the three joints
a’, b’ and c’ at a time.

3.

Move the direction plate in the direction of the arrow
to release the two joints d’.

REFERENCE:

When reattaching the direction plate,
engage the two joints d’ and move in the
direction of the arrow (See Fig.32).

Mode switch actuator

Direction plate

Direction link

Fig.30

Direction plate

Joints d'

Joint c'

Direction link

Slot z

Joint b'

Polywasher

Fig.31

Direction plate Mode rack assembly

Joint k'

Mode gear

Polywasher

Mode rack assembly

Joint a'

Joint k'

Joint l'

REFERENCE:

When reattaching the direction link,
move the direction plate in the direction
of the arrow and engage the three joint

a’, b’ and c’ at a time (See Fig.33).

Removing the mode rack assembly

(See Fig.31 and 32)

1.

Move the mode rack assembly in the direction of the
arrow to release the two joints k’ and the joint l’.

REFERENCE:

When reattaching, set the two k’ 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.32).

Joints d'

Fig.32

Direction link

Mode switch actuator

Polywasher

y

Mode gear

Direction plate

Mode rack assembly

Fig.33

1-13

KS-FX925R

Removing the gear base assembly / take
up gear / reflector gear (See Fig.34 to 36)

1.

Push in the pin e’ 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 f’ of the main
chassis.

REFERENCE:

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

Gear base assembly

Pin e'

Polywasher

Slot f'

Slot f'

Fig.34

Take up gear

Removing the reel driver / reel spindle

(See Fig.36)

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.

Reflector gear

Reel driver

Reel driver spring

Reel spindle

Main chassis

Fig.35

Reel driver

Reel driver spring

Reel spindle

Gear base assembly

Slots f’

Take up gear

1-14

Reflector gear

Polywasher

Fig.36

Removing the side bracket assembly

(See Fig.37 to 41)

1.

Remove the eject cam plate spring.

2.

Push the joint g‘ 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 h’ of the side
bracket assembly and from the two joints i’.

4.

Move the eject cam plate in the direction of the arrow
to release the joint j’.

KS-FX925R

Joint g'

CAUTION:

Joint i'

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

Side bracket assembly

Boss h'

Eject cam limiter

Side bracket assembly

Joint i'

Joint g'

Eject cam plate spring

Joint i'

Load rack

Fig.37

Boss h'

Eject cam limiter

Eject cam plate

Fig.39

Joint i'

Fig.38

Side bracket assembly

Boss h'

Eject cam plate

Fig.40

Load rack

Joint j'

Side bracket assembly

Eject cam plate

Joint j'

Fig.41

1-15

KS-FX925R

Removing the main motor assembly /
sub motor assembly (See Fig.42 to 44)

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 F attaching the main motor
assembly.

6.

Remove the two screws G attaching the sub motor
assembly.

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)

G

Polywasher

Fig.42

F

G

Mode gear

Polywasher

Reduction gear (A)

F

Main motor
assembly

Reduction
gear (A)

Polywasher

Sub motor
assembly

Spacer

Main motor assembly

Sub motor assembly

Main motor assembly

Sub motor assembly

Fig.43

Spacer

Fig.44

1-16

Adjustment method

KS-FX925R

Test Instruments reqired for adjustment

1.Digital osclloscope(100MHz)

2.Frequency Counter meter

3.Electric voltmeter

4.Wow & flutter meter

5.Test Tapes

VT724

VT739
VT712
VT703

6.Torque gauge

Measuring conditions(Amplifier section)

Power supply voltage

Load impedance

Line out

For playback frequency measurement

For wow flutter & tape speed measurement

for DOLBY level measurement

For head azimuth measurement

Cassette type for CTG-N
(mechanism adjustment)

4 (2Speakers connection)

DC14.4V(10.5~16V)

20k

Frequency Range

FM1 /FM2 : 87.5 MHz to 108.0 MHz
FM3 : 65 MHz to 74 MHz

AM : (MW) 522 kHz to 1620 kHz
(LW) 144 kHz to 279 kHz

DUMMY LOAD

Exclusive dummy load should be used for AM
and FM dummy load,there is a loss of 6dB
between SSG output and antenna input. The
loss of 6dB need not be considered since
direct reading of figures are applied in this
working standard.

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 receiving.

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).

Arrangement of Adjusting

Cassette Mechanism Section

Capstan motor

Cassette mechanism
(Surface)

Azimuth screw
(Forward side)

Playback head

Tape speed adjust

Azimuth screw
(Reverse side)

1-17