JVC KS-FX772R User manual

SERVICE MANUAL
CASSETTE RECEIVER
No.49694
Mar. 2002
COPYRIGHT 2002 VICTOR COMPANY OF JAPAN, LTD.
KS-FX772R
KS-FX772R
CD CHANGER CONTROL
SEL
TP/PTY
DISP
SSM
¢
4
FM/AM
T A P E
CD-
CH
DAB
SCM
MODE
78910 11 12
RND
RPT
MO
KS-FX772R
Area Suffix
E Continental Europe
Contents
Safety precaution
Disassembly method
Adjustment method
Description of major ICs
1-2
1-3
1-18
1-22

1-3
KS-FX772R
Press the eject button in the lower right part of the
front panel. Remove the front panel assembly from
the body.
1.
Removing the front panel assembly
(See Fig.1)
Prior to performing the following procedure, remove
the front panel assembly.
Release the four joints aon both sides of the front
chassis assembly and remove the front chassis
assembly toward the front.
1.
Removing the front chassis assembly
(See Fig.2 , 3)
Disassembly method
<Main body>
Fig.1
Fig.2
Fig.3
Front panel assembly
Eject button
Joint a
Joint a
Front chassis assembly
Front chassis
assembly
Heat sink Joint a
Joint a

1-4
KS-FX772R
Remove the three screws Aon the left side of the
body.
1.
Removing the heat sink (See Fig.4)
Prior to performing the following procedure, remove
the front panel assembly, the front chassis assembly
and the heat sink.
Turn over the body and unjoint the five joints bwith
the bottom cover and the body using a screwdriver.
1.
Removing the bottom cover
(See Fig.5 , 6)
Fig.4
Fig.5
Fig.6
Heat sink
AA
Joint b
Joint b
Joint b
Joint b
Joint b
Joint b
Bottom cover
Bottom cover
Rear panel
Rear panel

1-5
KS-FX772R
Prior to performing the following procedure, remove
the front panel assembly, the front chassis assembly,
the heat sink and the bottom cover.
Remove the screw B, the three screws C and the
two screws Dattaching the rear bracket on the back
of the body. Remove the rear panel.
Remove the two screws Eattaching the main board
on the bottom of the body. Disconnect connector
CN701 on the main board in the direction of the
arrow.
1.
2.
Removing the main board (See Fig.7 , 8)
Prior to performing the following procedure, remove
the front panel assembly, the front chassis assembly,
the heat sink, the bottom cover and the main board.
Remove the four screws Fattaching the cassette
mechanism section on the back of the top chassis.
1.
Removing the cassette mechanism section
(See Fig.9)
Fig.7
Fig.8
Fig.9
Rear panel
B
D
D
C
C
Main board
E
E
CN701
Cassette mechanism section
F
F
F
F
Top chassis

1-6
KS-FX772R
Prior to performing the following procedure, remove
the front panel assembly.
Remove the four screws Gattaching the rear cover
on the back of the front panel assembly.
Unjoint the eleven joints cwith the front panel and
the rear cover.
Remove the control switch board on the back of the
front panel.
1.
2.
3.
Removing the control switch board
(See Fig.10 ~ 12)
Fig.10
Fig.11
Fig.12
G
GG
G
Rear cover
Joint c
Joint c Joint c
Joint c
Front panel
Rear cover
Front panel
Control switch board

1-7
KS-FX772R
Turn the mode gear to set to RVS play or
subsequent mode.
Remove the cassette guide from the main chassis
while releasing each two joint tabs ain the direction
of the arrow.
1.
2.
Removing the cassette guide (See Fig.2)
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).
REFERENCE:
Remove the E-washer attaching the load arm.
Move the load arm in the direction of the arrow and
release the joint bon the cassette catch.
1.
2.
Removing the load arm (See Fig.3)
Fig.1
Fig.2
Mode gear
Cassette guide
Tab a
Tab a
Fig.3
Load arm
E-washer
Joint b

1-8
KS-FX772R
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.
Move the rear part of the cassette hanger assembly
in the direction of the arrow to release it from the two
joint bosses d.
Release the holder stabilizer spring from the hooks e
and f, then pull out from the cassette hanger
assembly.
Bring up the rear side of the cassette hanger
assembly to release the joint g and h.
Pull out the cassette catch from the cassette hanger
assembly.
1.
2.
3.
4.
5.
Removing the cassette hanger assembly /
cassette holder (See Fig.4 to 7)
Fig.4
Fig.5
Fig.7
Fig.6
Cassette holder assembly
Cassette holder assembly
Side bracket
Joints c
Cassette holder assembly
Cassette hanger assembly
Cassette hanger assembly
Cassette hanger
assembly
Boss d
Boss d
Cassette hanger assembly
Cassette stabilizer spring
Hook f
Hook h
Hook e
Hook g
Cassette holder
assembly Cassette catch

1-9
KS-FX772R
Remove the screw Aattaching the side bracket
assembly.
Detach the front side of the side bracket assembly
upward and pull out forward to release the joint iand
jin the rear.
1.
2.
Removing the side bracket assembly
(See Fig.8 to 10)
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 operation.
CAUTION:
Fig.9
Fig.10
Fig.8
A
Side bracket assembly
Side bracket assembly
Joint i
Joint j
Side bracket assembly
Boss k
Load rack
Boss k
Load rack
Joint i
Joint j

1-10
KS-FX772R
Remove the polywasher and pull out the pinch arm
(F) assembly.
Remove the compulsion spring.
1.
2.
Removing the pinch arm (F) assembly
(See Fig.11 and 12)
Remove the polywasher and pull out the pinch arm
(R) assembly.
1.
Removing the pinch arm (R) assembly
(See Fig.11 and 13)
Move the slide chassis assembly in the direction of
the arrow to release the two joints land remove from
the main chassis.
Remove the rack link.
1.
2.
Removing the slide chassis assembly
(See Fig.14 and 15)
When reassembling, first reattach the rack
link, and next fit the boss mand hook nof
the slide chassis assembly to the hole of
the main chassis, and engage the two joints
l.
CAUTION:
It is not necessary to remove the head
and the tape guide.
REFERENCE:
Fig.11
Fig.15
Fig.12
Fig.13
Fig.14
Polywasher
Polywasher Pinch arm
(F) assembly
Pinch arm
(R) assembly
Polywasher
Pinch arm (F) assembly
Compulsion spring
Pinch arm
(R) assembly Polywasher
Slide chassis assembly
Joint l
Joint l
Boss m
Hook n
Rack link
Head
Tape guide

1-11
KS-FX772R
Remove the band attaching the wire to the head.
Remove the two screws B, the head and the head
support spring.
Remove the pinch arm spring from the tape guide.
Remove the tape guide and the pinch spring arm.
1.
2.
3.
4.
Removing the head / tape guide
(See Fig.16 and 17)
Remove the belt at the bottom.
Remove the two polywashers on the upper side.
Pull out each flywheel assembly downward.
1.
2.
3.
Removing the flywheel assembly (F) & (R)
(See Fig.18 and 19)
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).
CAUTION:
It is not necessary to remove the slide
chassis assembly.
REFERENCE:
It is not necessary to remove the slide
chassis assembly.
REFERENCE:
Fig.17
Fig.19
Fig.16
Fig.18
B
Slide chassis assembly
Head Tape guide
B
Pinch arm spring
Head
Head support spring
Tape guide
Pinch spring arm
Slid chassis assembly
Flywheel assembly (F)
Flywheel assembly (R)
Belt Polywasher
Polywasher
Flywheel assembly (F)
Flywheel assembly (R)
o
o

1-12
KS-FX772R
Push and turn counterclockwise the spring holder (F)
to release the three joints pon the bottom of the
flywheel.
The spring holder (F), the TU spring and the friction
gear play come off.
Remove the polywasher and felt.
1.
2.
3.
Disassembling the flywheel assembly (F)
(See Fig.20 and 21)
Push and turn clockwise the spring holder (R) to
release the three joints qon the bottom of the
flywheel.
The spring holder (R), the FF spring and the friction
gear FF come off.
Remove the polywasher and the felt.
1.
2.
3.
Disassembling the flywheel assembly (R)
(See Fig.20 and 22)
Remove the two screws Cattaching the reel board.
Move the reel board in the direction of the arrow to
release the joint r.
Unsolder the wires if necessary.
1.
2.
3.
Removing the reel board
(See Fig.23 and 24)
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.
CAUTION:
Fig.24
Fig.20
Fig.21 Fig.22
Fig.23
Flywheel assembly (F) Flywheel assembly (R)
Joints p
Joint p
Joints q
Joint q
Polywasher
Spring holder (F)
TU spring
Polywasher
Spring holder (R)
FF spring
Friction gear play
Friction gear FF
Flywheel assembly (F) Flywheel assembly (R)
FFC pad
FFC pad
Joint r
Reel board
C
C
CT-1 switch
ST-BY switch
Soldering
MODE switch
Felt Felt

1-13
KS-FX772R
Move the gear base arm in the direction of the arrow.
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.
Remove the gear base arm from the main chassis
while releasing the two joints s.
Move the gear base link assemby in the direction of
the arrow to release the two joints t.
1.
2.
3.
4.
Removing the gear base arm / gear base
link assembly (See Fig.25 to 27)
Push each joint hook uof the FFC pad and remove
toward the bottom.
1.
Removing the FFC pad
(See Fig.27 and 29)
When reattaching the gear base arm,
make sure that the boss on the gear
base assembly is inside the gear base
spring.
REFERENCE:
Fig.25
Fig.26
Fig.27
FFC pad
Gear base link assembly Gear base arm
Gear base
link assembly
Gear base arm
FFC pad
Joint t
Joint t
Joints s
Hook u
Hook u
Gear base arm
Screwdriver
Gear base spring

1-14
KS-FX772R
Remove the polywasher on the bottom and pull out
the mode gear.
1.
Removing the mode gear
(See Fig.28 and 31)
Move the mode rack assembly in the direction of the
arrow to release the two joints b’ and the joint c’.
1.
Removing the mode rack assembly
(See Fig.29 and 30)
Remove the polywasher attaching the direction link.
Bring up the direction link to release the three joints
x, yand zat a time.
Move the direction plate in the direction of the arrow
to release the two joints a’.
1.
2.
3.
Removing the direction link / direction
plate (See Fig.29 to 31)
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.30).
REFERENCE:
Pull out the mode switch actuator at the bottom.
1.
Removing the mode switch actuator
(See Fig.28, 29 and 31)
When reattaching the mode switch
actuator to the main chassis, make sure to
set on the shaft and insert vinto the slot w.
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 joint
x, yand zat a time (Refer to Fig.31).
REFERENCE:
Fig.28
Fig.30
Fig.31
Fig.29
Polywasher
Mode switch actuator Mode gear
Direction plate Direction link
Mode rack assembly
Slot w
Direction plate
Joints a'
Joint z
Direction link Polywasher
Joint y Joint x
Direction plate Mode rack assembly
Joint c'
Joint b'
Joint b'
Polywasher
Mode gear
Mode switch actuator
Direction link
Direction plate
Mode rack assembly
v
Joints a'

1-15
KS-FX772R
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.
Remove the polywasher on the bottom and pull out
the take up gear.
Move the gear base assembly in the direction of the
arrow to release it from the two slots e’of the main
chassis.
1.
2.
3.
Removing the gear base assembly / take
up gear / reflector gear (See Fig.32 to 34)
Draw out the reel driver from the shaft on the main
chassis and remove the reel driver spring and the
reel spindle respectively.
1.
Removing the reel driver / reel spindle
(See Fig.34)
The reel driver is damaged when
removed. Please replace with a new
one.
CAUTION:
The parts are damaged when removed.
Please replace with new ones.
REFERENCE:
Fig.32
Fig.33
Fig.34
Gear base assembly
Pin d'
Slot e'
Slot e'
Polywasher
Reflector gear
Take up gear
Reel driver spring
Reel driver spring
Reel driver
Reel driver
Reel spindle
Reel spindle
Gear base assembly
Slots e’
Main chassis
Reflector gear Polywasher
Take up gear

1-16
KS-FX772R
Remove the eject cam plate spring.
Push the joint f‘through the slot to remove the load
rack downward.
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’.
Move the eject cam plate in the direction of the arrow
to release the joint i’.
1.
2.
3.
4.
Removing the side bracket assembly
(See Fig.35 to 39)
When reassembling, confirm operation of
each part before reattaching the eject cam
plate spring.
CAUTION:
Fig.35
Fig.37
Fig.39
Fig.36
Fig.38
Joint f'
Load rack
Eject cam plate spring
Eject cam limiter
Side bracket assembly
Boss g'
Joint h'
Load rack
Joint f'
Joint h'
Boss g'Eject cam limiter
Side bracket assembly
Joint h' Joint h'
Eject cam plate
Side bracket assembly
Boss g'
Joint i'
Eject cam plate
Side bracket assembly
Eject cam plate
Joint i'

1-17
KS-FX772R
Remove the belt at the bottom.
Remove the polywasher and pull out the mode gear.
Pull out the reduction gear (B).
Remove the polywasher and pull out the reduction
gear (A).
Remove the two screws Dattaching the main motor
assembly.
Remove the two screws Eattaching the sub motor
assembly.
Unsolder the wires on the reel board if necessary.
1.
2.
3.
4.
5.
6.
7.
Removing the main motor assembly /
sub motor assembly (See Fig.40 to 42)
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.
CAUTION:
Fig.40
Fig.41
Fig.42
Belt
Polywasher
Polywasher
Polywasher
Mode gear
Reduction
gear (A)
Main motor
assembly
D
Sub motor
assembly
E
Reduction gear (B)
Reduction gear (B)
Reduction gear (A)
ED
Main motor assembly
Sub motor assembly
Spacer
Spacer
Sub motor assembly
Main motor assembly

1-18
KS-FX772R
Adjustment method
1.Digital osclloscope(100MHz)
Measuring conditions(Amplifier section)
Power supply voltage
Load impedance
Line out level / Impedance
for DOLBY level measurement
For playback frequency measurement
For wow flutter & tape speed measurement
For head azimuth measurement
Cassette type for CTG-N
(mechanism adjustment)
DC14.4V(11V to 16V allowance)
4 (4 to 8 allowance)
2.0V / 20k
Tuner area
Band range
FM : 87.5MHz to 108.0MHz
AM : (MW) 522kHz to 1620 kHz
(LW) 144kHz 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.
Test Instruments reqired for adjustment
2.Frequency Counter meter
3.Electric voltmeter
4.Wow & flutter meter
5.Test Tapes
VT724
VT739
VT712
VT703
6.Torque gauge

1-19
KS-FX772R
Head section view
Cassette mechanism
(Surface)
Arrangement of adjusting & test points
Motor assembly
Tape speed adjust
Playback head
Azimuth screw B
(Reverse)
Azimuth screw B
(Reverse) Azimuth screw A (Forward)
Azimuth screw A
(Forward)
Playback Head

1-20
KS-FX772R
C401
C402
C403 C404
C405 C406
C407
C408
C409
C410
C411
C412
C413 C414 C416
C417
C418
C419
C421
C422
C423
C424
C425
CJ401
B405
B403
D401 D402
IC402
Q401
Q402
Q403
R401
R402
R403
R404 R405
R406
R407
R408
R410
R411
R412
R413
R414
R415
R416
R417
R418
R420
B413
R422
R423
R424
R425
R426
VR401
VR402
IC401
CJ403
B412
B407
B401
B408
B410
B406
B409 B404
C415
B402
B411
2
1
2
1
11
21
31
1
FSMW1093A
1
1
T11
VR401:Rch
(Dolby NR Frequency response adj)
Arrangment of adjusting
Head amplifier board section (Reverse side)
Information for using a car audio service jig
1. We're advancing efforts to make our extension cords common for all car audio products.
Please use this type of extension cord as follows.
2. As a U-shape type top cover is employed, this type of extension cord is needed to check operation of the
mechanism assembly after disassembly.
3. Extension cord : EXTKSRT002-18P ( 18 pin extension cord ) For connection between mechanism assembly
and main board assembly.
Check for mechanism driving section such as motor ,etc..
Disassembly method
1. Remove the bottom cover.
2. Remove the front panel assembly.
3. Remove the top cover .
4. Install the front panel.
5. Confirm that current is being carried by connecting
an extension cord jig.
Note
Available to connect to the CP701 connector when in-
stalling the front panel.
Cassette mechanism
Front panel assembly
EXTKSRT002-18P
Extension cord
Main board
VR402:Rch
(Dolby NR leveladj)
EXTKSRT002-18P
to Main board
to Cassette mechanism

1-21
KS-FX772R
Item Conditions Adjustment and Confirmation methods S.Values Adjust
Head
azimuth
adjustment
Head height adjustment
Adjust the azimuth directly. When you
adjust the height using a mirror tape,
remove the cassette housing from the
mechanism chassis. After installing the
cassette housing, perform the azimuth
adjustment.
Load the SCC-1659 mirror tape. Adjust with
height adjustment screw A and azimuth
adjustment screw B so that line A of the
mirror tape runs in the center between Lch
and Rch in the reverse play mode.
After switching from REV to FWD then to
REV, check that the head position set in
procedure 1 is not changed. (If the position
has shifted, adjust again and check.)
Adjust with azimuth adjustment screw B so
that line B of the mirror tape runs in the
center between Lch and Rch in the forward
play mode.
Test tape:
SCC-1659
VT703(10kHz)
Test tape: VT712
(3kHz)
Test tape: VT724
(1kHz)
VT739
(63Hz / 1kHz / 10kHz)
1.
Tape speed
and wow
flutter
confirmation
2.
Play back
frequency
response
confiramation
3.
1.
2.
3.
Check to see if the reading of the F, counter /
wow flutter meter is within 3015 3045(FWD
/ REV), and less than 0.35% (JIS RMS).
In case of out of specification, adjust the
motor with a built-in volume resistor.
1.
2.
Play test tape VT724, and set the volume
position at 2V.
Play test tape VT739 and confirm.
1kHz / 10kHz: -1 3dB,
1kHz / 63Hz: 0 3dB,
When 10kHz is out of specification, it will be
necessary to read adjust the azimuth.
1.
2.
3.
Load VT724 (1kHz) and play it back in
the reverse play mode.
Set the Rch output level to max.
Load VT703 (10kHz) and play it back in
the forward play mode. Adjust the Rch
and Lch output levels to max, with
azimuth adjustment screw B. In this case,
the phase difference should be within 45 .
Engage the reverse mode and adjust the
output level to max, with azimuth
adjustment screw C.
(The phase difference should be 45 or
more.)
When switching between forward and
reverse modes, the difference between
channels should be within 3dB. (Between
FWD L and R, REV L and R.)
When VT721 (315Hz) is played back,
the level difference between channels
should be within 1.5dB.
1.
2.
3.
4.
5.
Head azimuth adjustment
Tape speed:
3015
3045Hz
Wow
flutter: less
than 0.35%
Speaker out
1kHz / 63Hz
: 0 3db
1kHz / 10kHz
: -1 3db
Built-in volume
resistor
The tuner section is of an adjustment-freedesign. In case the tuner is in trouble, replace the tuner pack.
A line
B line
Head shield
PBHead
FWD Adj B
REV Adj C HEIGHT Adj A
phase
(0 ) (45 )
Head shield
The head is at low position
during.
The head is at High position
during REV.
Output
level:
Maximum