JVC MX-J270V User manual

SERVICE MANUAL
COMPACT COMPONENT SYSTEM
No.20880
Nov. 2000
COPYRIGHT 2000 VICTOR COMPANY OF JAPAN, LTD.
MX-J270V
Contents
Safety Precautions
Important for laser products
Preventing static electricity
Disassembly method
Adjustment method
Flow of functional operation
until TOC read
Maintenance of laser pickup
Replacement of laser pickup
Description of major ICs
1-2
1-3
1-4
1-5
1-22
1-26
1-27
1-27
1-28
Area Suffix
US
UX Singapore Saudi Arabia
PlayBack
Control
VIDEO CD
CD
CD
CD
STANDBY
VOLUME
CD
CD
CD
FM /AM
CD
PLAY REC/PLAY
AUTO REVERSE
TAPE
MIC LEVEL
1 BIT
DUAL D/A CONVERTER
AUX
PHONES
MX-J270V
+
–
MIC
MIN MAX
AUTO REVERSE
PLAY& EXCHANGER
VIDEO CD
NTSC/PAL COMPATIBILITY
REC
START/STOP
KEY CONTROL
DUBBING
CD REC START NTSC/PALPAL AUTO
RANDOM
REPEAT
–PRESET +TUNING / VCD NUMBER
REVERSE MODE TAPE A/B SOUNDMODE ACTIVE BASS EX.
PREV NEXT
ECHO
+
–
SELECT
MPX/V.REPLACE/V.MASKING
EJECT EJECT
1
CD
TAPE
CLOCK
ECHO SET
TIMER
SLEEP
SELECT
–+
RM-SMXJ111VREMOTE CONTROL
2 3
456
PLAYMODE
STILL
CD3CD2CD1
A –TAPE - B RECPAUSE
SOUND
MODE VOLUME KEY
CONTROL
SHIFT FM MODE
789
10 + 10
HIGHLIGHT
ON SCREEN
V.INTRO
PREV NEXT RETURN SELECT
FM/AM AUX
i
I
MX-J270V
SP-MXJ270V
CA-MXJ270V
SP-MXJ270V

MX-J270V
1-2
Safety Precautions
1.This design of this product contains special hardware and many circuits and components specially
for safety purposes. For continued protection, no changes should be made to the original design
unless authorized in writing by the manufacturer. Replacement parts must be identical to those
used in the original circuits. Services should be performed by qualified personnel only.
2. Alterations of the design or circuitry of the product should not be made. Any design alterations of
the product should not be made. Any design alterations or additions will void the manufacturer`s
warranty and will further relieve the manufacture of responsibility for personal injury or property
damage resulting therefrom.
3. Many electrical and mechanical parts in the products have special safety-related characteristics.
These characteristics are often not evident from visual inspection nor can the protection afforded
by them necessarily be obtained by using replacement components rated for higher voltage,
wattage, etc. Replacement parts which have these special safety characteristics are identified in
the Parts List of Service Manual. Electrical components having such features are identified by
shading on the schematics and by ( ) on the Parts List in the Service Manual. The use of a
substitute replacement which does not have the same safety characteristics as the recommended
replacement parts shown in the Parts List of Service Manual may create shock, fire, or other
hazards.
4. The leads in the products are routed and dressed with ties, clamps, tubings, barriers and the
like to be separated from live parts, high temperature parts, moving parts and/or sharp edges
for the prevention of electric shock and fire hazard. When service is required, the original lead
routing and dress should be observed, and it should be confirmed that they have been returned
to normal, after re-assembling.
5. Leakage currnet check (Electrical shock hazard testing)
After re-assembling the product, always perform an isolation check on the exposed metal parts
of the product (antenna terminals, knobs, metal cabinet, screw heads, headphone jack, control
shafts, etc.) to be sure the product is safe to operate without danger of electrical shock.
Do not use a line isolation transformer during this check.
Plug the AC line cord directly into the AC outlet. Using a "Leakage Current Tester", measure
the leakage current from each exposed metal parts of the cabinet , particularly any exposed
metal part having a return path to the chassis, to a known good earth ground. Any leakage
current must not exceed 0.5mA AC (r.m.s.)
Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000 ohms
per volt or more sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by
a 0.15 F AC-type capacitor between an exposed
metal part and a known good earth ground.
Measure the AC voltage across the resistor with the
AC voltmeter.
Move the resistor connection to eachexposed metal
part, particularly any exposed metal part having a
return path to the chassis, and meausre the AC
voltage across the resistor. Now, reverse the plug in
the AC outlet and repeat each measurement. voltage
measured Any must not exceed 0.75 V AC (r.m.s.).
This corresponds to 0.5 mA AC (r.m.s.).
Warning
1.This equipment has been designed and manufactured to meet international safety standards.
2. It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
3. Repairs must be made in accordance with the relevant safety standards.
4. It is essential that safety critical components are replaced by approved parts.
5. If mains voltage selector is provided, check setting for local voltage.
Good earth ground
Place this
probe on
each exposed
metal part.
AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)
1500 10W
0.15 F AC TYPE
!
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.

MX-J270V
1-3
Important for laser products
1.CLASS 1 LASER PRODUCT
2.DANGER : Invisible laser radiation when open and inter
lock failed or defeated. Avoid direct exposure to beam.
3.CAUTION : There are no serviceable parts inside the
Laser Unit. Do not disassemble the Laser Unit. Replace
the complete Laser Unit if it malfunctions.
4.CAUTION : The compact disc player uses invisible
laserradiation and is equipped with safety switches
whichprevent emission of radiation when the drawer is
open and the safety interlocks have failed or are de
feated. It is dangerous to defeat the safety switches.
5.CAUTION : If safety switches malfunction, the laser is able
to function.
6.CAUTION : Use of controls, adjustments or performance of
procedures other than those specified herein may result in
hazardous radiation exposure.
VARNING : Osynlig laserstrålning är denna del är öppnad
och spårren är urkopplad. Betrakta ej strålen.
VARO : Avattaessa ja suojalukitus ohitettaessa olet
alttiina näkymättömälle lasersäteilylle.Älä katso
säteeseen.
ADVARSEL : Usynlig laserstråling ved åbning , når
sikkerhedsafbrydere er ude af funktion. Undgå
udsættelse for stråling.
ADVARSEL : Usynlig laserstråling ved åpning,når
sikkerhetsbryteren er avslott. unngå utsettelse
for stråling.
REPRODUCTION AND POSITION OF LABELS
WARNING LABEL
DANGER : Invisibie laser radiation
when open and interlock or
defeated.
AVOID DIRECT EXPOSURE TO
BEAM (e)
VARNING : Osynlig laserstrålning är
denna del är öppnad och spårren är
urkopplad. Betrakta ej strålen. (s)
VARO : Avattaessa ja suojalukitus
ohitettaessa olet alttiina
näkymättömälle lasersäteilylle.Älä
katso säteeseen. (d)
ADVARSEL :Usynlig laserstråling
ved åbning , når
sikkerhedsafbrydere er ude af
funktion. Undgå udsættelse for
stråling. (f)
CLASS 1
LASER PRODUCT
!
CAUTION
Please use enough caution not to
see the beam directly or touch it
in case of an adjustment or operation
check.

MX-J270V
1-4
Preventing static electricity
1. Grounding to prevent damage by static electricity
Electrostatic discharge (ESD), which occurs when static electricity stored in the body, fabric, etc.is discharged,
can destroy the laser diode in the traverse unit (optical pickup). Take care to prevent this when performing repairs.
2. About the earth processing for the destruction prevention by static electricity
In the equipment which uses optical pick-up (laser diode), optical pick-up is destroyed by the static electricity of
the work environment.
Be careful to use proper grounding in the area where repairs are being performed.
2-1 Ground the workbench
Ground the workbench by laying conductive material (such as a conductive sheet) or an iron plate over
it before placing the traverse unit (optical pickup) on it.
2-2 Ground yourself
Use an anti-static wrist strap to release any static electricity built up in your body.
3. Handling the optical pickup
1. In order to maintain quality during transport and before installation, both sides of the laser diode on the
replacement optical pickup are shorted. After replacement, return the shorted parts to their original condition.
(Refer to the text.)
2. Do not use a tester to check the condition of the laser diode in the optical pickup.The tester's internal power
source can easily destroy the laser diode.
4. Handling the traverse unit (optical pickup)
1. Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit.
2. Cut off the shorted part of the flexible cable using nippers, etc. after replacing the optical pickup. For specific
details, refer to the replacement procedure in the text.Remove the anti-static pin when replacing the traverse
unit. Be careful not to take too long a time when attaching it to the connector.
3. Handle the flexible cable carefully as it may break when subjected to strong force.
4. It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it
Conductive material
(conductive sheet) or iron plate
(caption)
Anti-static wrist strap

MX-J270V
1-5
Remove the six screws Aattaching the metal cover
on the back of the body.
Remove the two screws Bon both sides of the body.
Remove the metal cover from the body while lifting
up the rear part of the metal cover.
1.
2.
3.
<Main body>
Removing the metal cover(See Fig.1 to 3)
Disassembly method
Fig.3
Fig.2
Fig.1
Metal cover
A
A
A
Metal cover
B
Metal cover
B

MX-J270V
1-6
Prior to performing the following procedures, remove
the metal cover.
Disconnect the card wire from connector CN308 and
CN309 connecting the CD servo board and the main
board.
Disconnect the harness from CN310 on the main
board.
Remove the two screws C attaching the CD changer
mechanism assembly on the top of the body.
Remove the plastic rivet afixing the main board to
the front panel assembly on the left side of the body.
Remove the two screws Dfrom the rear panel.
Cut off the band band band cwhich bundle two
harnesses coming from the MIC/headphone board
and one harness coming from the video board,
respectively.
Detach upward the rear part of the CD changer
mechanism assembly while pulling the front panel
assembly and the rear panel outward, then pull out
the front part backward and upward.
1.
2.
3.
4.
5.
6.
7.
Removing the CD changer mechanism
assembly (See Fig.4 to 7)
Fig.6
Fig.5
Fig.4
Fig.7
Pull outward
C
Main board
CN303
Plastic rivet aCD changer mechanism assembly
Rear panel
Front panel
assembly
D
Rear panel
CD changer
mechanism
assembly
CD changer mechanism
assembly
Rear panel Front panel
assembly
Pull outward
Main board
Main board
Band b
Band c
CN308
CN309
CN310

MX-J270V
1-7
Prior to performing the following procedures, remove
the metal cover and the CD changer mechanism
assembly.
Disconnect the card wires from connector CN302,
CN306, CN307 and the harness from CN301,
CN305 on the inside of the main board.
Turn over the body and remove the four screws E.
Release the joint dand eon both sides of the body
using a screwdriver, and detach the front panel
assembly toward the front.
1.
2.
3.
Removing the front panel assembly
(See Fig.8 to 11)
Fig.9
Fig.8
Fig.10
Fig.11
Main board CN301
CN302
CN306 CN307
CN312
CN305
EFront panel
assembly
Front panel
assembly
Joint d
Front panel
assembly Joint e
(Bottom)

MX-J270V
1-8
Prior to performing the following procedures, remove
the metal cover and the CD changer mechanism
assembly.
It is not necessary to remove the front panel
assembly.
Remove the two screws Fand the rear cover on the
back of the body.
Remove the four screws Gand the seven screws H
attaching the main board and the heat sink to the
rear panel.
Remove the screw Iattaching the rear panel to the
chassis base.
Remove the two screws Jattaching the rear panel to
the voltage selector.
Remove the two screws Kattaching the rear panel to
the video board.
Release the lower two joints fand gon both sides of
the rear panel using a screwdriver and detach the
rear panel backwards.
1.
2.
3.
4.
5.
6.
Removing the rear cover, the rear panel,
the voltage selector and the video board
(See Fig.12 to 15)
Fig.12
Fig.13
Fig.14
Fig.15
I
Rear panel
G
Rear panel
F
F
Rear cover
H
G
H
Rear panel Joint f
Rear panel
Joint g
(To Earth bracket)
J
K

MX-J270V
1-9
Prior to performing the following procedures, remove
the metal cover, the CD changer mechanism
assembly, the rear cover, the rear panel, the voltage
selector and the video board.
It is not necessary to remove the front panel
assembly.
Disconnect the card wires from connector CN302,
CN306, CN307 and the harnesses from CN301,
CN305, CN901A and CN901B on the inside of the
main board.
Disconnect the harness from CN312 on the video
board.
From the right side of the body, remove the screw M
attaching the main board to the chassis base.
1.
2.
3.
Removing the main board
(See Fig.16 to 19)
Prior to performing the following procedure, remove
the rear cover, rear panel, voltage selector and the
video board.
Remove the two screws Nattaching the heat sink to
the main board. Remove the IC bracket 1 and 2 on
the back of the heat sink.
Pull out the heat sink toward you.
1.
2.
~To remove the heat sink from
the main board~
Prior to performing the following procedures, remove
the main board.
Release the two joints hand iusing a screwdriver
and detach the DSP board toward you.
1.
Removing the DSP board (See Fig.19)
Fig.16
Fig.17 M
Main board
Main board CN306 CN307
CN302
CN305
CN301
CN901A,CN901B
Fig.18
Heat sink
N
Main board
Fig.19
Heat sink
IC bracket 2
IC bracket 1
CN312
DSP board
DSP board
Joint i
Joint h
DSP board
Video board

MX-J270V
1-10
Prior to performing the following procedure, remove
the metal cover, the CD changer mechanism
assembly and the voltage selector.
Disconnect the harness from connector CN901A and
CN901B on the inside of the main board.
Cut off the tie band jof the power transformer
assembly and unsolder the power cord.
(Make sure to bundle the wires after repair.)
Remove the four screws Oattaching the power
transformer assembly.
When removing the power transformer assembly
with the power cord, remove the rear panel and pull
out the power cord stopper from the bottom chassis
upward.
1.
2.
3.
Removing the power transformer
assembly
(See Fig.20 to 22)
Fig.20
Fig.21
Fig.22
O
Power transformer assembly
CN901A,CN901B
OPower transformer
assembly
Tie band j
Power transformer
assembly
Power cord stopper
Rear panel
Voltage selector board
Voltage selector board
Voltage selector board
Video board
Video board
Front panel
assembly

MX-J270V
1-11
Prior to performing the following procedure, remove
the metal cover, the CD changer mechanism
assembly and the front panel assembly.
Remove the two screws Pattaching the MIC
/headphone board.
Pull out the MIC LEVEL knob from front side.
Prior to performing the following procedure, remove
the metal cover, the CD changer mechanism
assembly and the front panel assembly.
Disconnect the card wire from connector CN305 on
the cassette amplifier board.
Remove the eight screws Qattaching the cassette
mechanism assembly.
Detach the cassette mechanism assembly toward
you.
1.
2.
1.
2.
3.
Prior to performing the following procedure, remove
the cassette mechanism assembly.
Disconnect the card wire from connector CN301 and
CN302 on the cassette amplifier board.
Remove the six screws Rattaching the cassette
amplifier board.
Unsolder the soldering kon the harness for the DC
motor.
Detach the cassette amplifier board toward you.
1.
2.
3.
4.
<Front panel assembly>
Removing the MIC/headphone board
(See Fig.23 and 24)
Removing the cassette mechanism
assembly
(See Fig.25)
Removing the cassette amplifier board
(See Fig.26)
Fig.25
Fig.23
Fig.24
Fig.26
Q
Q
QQ
Cassette
mechanism
assembly
Cassette amplifier board
CN302 CN301
Cassette mechanism
board
DC motor
P
MIC/headphone board
MIC LEVEL knob
Q
Q
CN305
Cassette amplifier
board
R
RR
RR
R
Soldering k
Front panel assembly
Front panel assembly

MX-J270V
1-12
Disconnect the card wire from connector CN306 on
the cassette amplifier board.
Remove the four screws Sattaching the front panel
assembly.
Remove the four screws Tattaching the front panel
assembly.
Unsolder FW701, FW702, FW703, FW704 and
FW705 on the display board. Disconnect the
harnesses extending from the power switch board,
the eject switch board, the volume board and the
multi-control board respectively
1.
2.
3.
4.
Removing the display board and the
bracket (See Fig.27 and 28)
Prior to performing the following procedure, remove
the display board.
Pull out the volume knob on the front side of the front
panel assembly and remove the nut attaching the
volume board.
Unhook the two hooks lon the back of the front
panel assembly and detach the volume board.
1.
2.
Remove the eight screws Uattaching the multi-
control board.
1.
Removing each board in the front panel
assembly (See Fig.29 to 31)
~Removing the multi-control board~
(See Fig.29)
~Removing the volume board~
(See Fig.30 and 31)
Remove the three screws Wattaching the power
switch board.
1.
Remove the four screws Vattaching the eject switch
board.
1.
~Removing the eject switch board ~
(See Fig.29)
~Removing the power switch board~
(See Fig.29)
Prior to performing the following procedure, remove
the metal cover, the CD changer mechanism
assembly and the front panel assembly.
S
Bracket
FW703
FW704
FW701
FW702
FW705
Display board
T
TT
Display board
VW
U
U
U
U
U
U
Power
switch
board
Eject
switch
board
Volume
board
Multi-
control
board
Volume
board Hooks l
Volume
knob
Fig.27
Fig.28
Fig.29
Fig.30 Fig.31
Front panel
assembly
Front panel assembly
Front panel assembly
Front panel assembly

MX-J270V
1-13
CD Traverse Mechanism Type:C3CN Section
Removing the CD Servo control board
(See Fig.1)
1.
2.
3.
4.
5.
Remove the Metal cover.
Remove the CD Traverse mechanism assembly.
From bottom side the CD Traverse mechanism
assembly, remove the one screw A retaining the CD
Servo control board.
From the connectors CN601, CN603, CN604 on the CD
Servo control board, disconnect the card wire, from the
connector CN602, disconnect the six pin connector
wire.
Disengage the two engagements "a" , remove the CD
Servo control board.
Removing the CD tray assembly
(See Fig.2~4)
1.
2.
3.
4.
5.
6.
7.
8.
9.
Remove the front panel assembly.
Remove the CD Traverse mechanism assembly.
Remove the CD Servo control board.
Remove the screw B retaining the disc stopper
(See Fig.3).
Remove the three screws C retaining theT.bracket
(See Fig.3).
From the clamper base section "c" , remove both of the
edges fixing the rod(See Fig.2 and 3).
Remove the screw D retaining the clamper assembly
(See Fig.3).
From the left side face of the chassis assembly, remove
the one screw E retaining both of the return spring and
lock lever(See Fig. 4).
By removing the pawl at the section "d" fixing the return
spring, dismount the return spring(See Fig.4).
Remove the three lock levers(See Fig.4).
10.
Fig.1
Fig.2
Fig.3
Fig.4
CD servo control board
CN604
CN603
CN601
a
A
a
b
c
Rod
T.Braket
Clamper base
B
C
D
T.Braket Disc stopper
Lod stopper
(C/J version only)
Clamper ass'y
c
b
d
Lock lever
Return spring
E
CN
602
C
C

MX-J270V
1-14
11.
12.
Check whether the lifter unit stopper has been caught
into the hole at the section "e" of CD tray assembly as
shown in Fig.5.
Make sure that the driver unit elevator is positioned as
shown in Fig.6 from to the second or fifth hole on the
left side face of the CD Traverse mechanism assembly.
Fig.5
Fig.7Fig.6
Fig.8 Fig.9
[Caution] In case the driver unit elevator is not at above
position, set the elevator to the position as
shown in Fig.7 by manually turning the pulley
gear as shown in Fig.8.
13.
14.
15.
Manually turn the motor pulley in the clockwise
direction until the lifter unit stopper is lowered from the
section "e" of CD tray assembly(See Fig.8).
Pull out all of the three stages of CD tray assembly in
the arrow direction "f" until these stages stop
(See Fig.6).
At the position where the CD tray assembly has
stoppend, pull out the CD tray assembly while
pressing the two pawls "g and g' "on the back side of
CD tray assembly(See Fig.9).In this case, it is easy to
pull out the assembly when it is pulled out first from the
stage CD tray assembly.
CD tray
assembly
e
Drive unit of elevator
CD tray assembly
f
Refer to Fig.7 Pawl
Chassis assembly
Pulley gear
Motor pulley
Pawl ,
CD tray assembly
Stopper
g
g g'

MX-J270V
1-15
Removing the CD mechanism
assembly (See Fig.10)
1.
2.
While turning the cams R1 and R2 assembly in the
arrow direction "h", align the shaft "i" of the CD
mechanism assembly to the position shown in Fig.10.
Remove the four screw F retaining the CD mechanism
assembly.
Removing the CD mechanism
(See Fig.11 and 12 )
1.
2.
For dismounting only the CD mechanism without
removing the CD mechanism assembly, align the shaft
"j" of the CD mechanism assembly to the position
shown Fig.11 while turning the cam R1 and R2
assembly in the arrow direction "k".
By raising the CD mechanism assembly in the arrow
direction "l" , remove the assembly from the lifter unit
(See Fig.12).
Fig.10
Fig.12
Fig.11
Fig.13
Removing the CD pick unit
(See Fig.13 )
1.
2.
3.
4.
Move the cam gear in the arrow direction m .Then, the
CD pickup unit will be moved in the arrow direction n .
According to the above step, shift the CD pickup unit to
the center position.
While pressing the stopper retaining the shaft in the
arrow direction o , pull out the shaft in the arrow
direction p .
After dismounting the shaft from the CD pickup unit,
remove the CD pickup unit
F
Cams R1, R2 assembly
i
CD mechanism assembly
F
h
Arrow
F
F
Lifter unit
CD mechanism
l
Arrow
Cam R1, R2 assembly
k
Arrow
j
CD Pickup unit
CD mechanism
Shaft
Cam gear
Shaft
Shaft
Stopper Stopper
n
m
p
o

MX-J270V
1-16
Removing the actuator motor board
(See Fig.14, 15)
1.
2.
3.
Absorb the four soldered positions "q" of the right and
left motors with a soldering absorber(See Fig.14).
Remove the two screws G retaining the actuator motor
board(See Fig.14).
Remove the two screws H retaining the tray select
switch board(See Fig.15).
Removing the cam unit
(See Fig.15 to 18 )
1.
2.
3.
4.
5.
Remove the CD mechanism assembly.
While turning the cam gear r, align the pawl "s" position
of the drive unit to the notch position(Fig.15) on the cam
gear r.
Pull out the drive unit and cylinder gear(See Fig.17).
While turning the cam gear r, align the pawl "t" position
of the select lever to the notch position(Fig.18) on the
cam gear r.
Remove the four screws I retaining the cam unit(cam
gear r and cams R1/R2 assembly)(See Fig.18). Fig.14
Fig.16
Fig.15
Fig.18
Fig.17
G
Motor L Motor R
qq
G
Actuator motor board
Cam gear r
Drive unit
s
Chassis assembly
Tray select
switch board
CN802
CN801
CN804 H
I
I
I
Select lever
Cams R1, R2 assembly
Cam unit
Cam gear L
Cylinder gear
Drive unit
t

MX-J270V
1-17
Fig.19
Fig.21
Fig.20
Fig.22
[Note] When the chassis assembly is turned over under
the conditions wherein the gear bracket and belt
have been removed, then the pulley gear as well
as the gear, etc. constituting the gear unit can
possibly be separated to pieces. In such a case,
assemble these parts by referring to the assembly
and configuration diagram in Fig. 22.
Removing the actuator motor and belt
(See Fig.19 to 22)
1.
2.
3.
4.
5.
Remove the two screws J retaining the gear bracket
(See Fig.19).
While pressing the pawl "u" fixing the gear bracket in
the arrow direction, remove the gear bracket
(See Fig.19).
From the notch "v section" on the chassis assembly
fixing the edge of gear bracket, remove and take out the
gear bracket(See Fig.20).
Remove the belts respectively from the right and left
actuator motor pulleys and pulley gears(See Fig. 19).
After turning over the chassis assembly, remove the
actuator motor while spreading the four pawls "w" fixing
the right and left actuator motors in the arrow
direction(See Fig. 21).
J
Pulley gear
J
Belt
Motor pulley
Belt
Pully gear
Motor pulley
Gear bracket
u
Pawl
w
Actuator motor
w
Chassis assembly
v
Gear bracket
Pulley gear
Gear B
Cylinder gear
Gross gear U
Gear C
Gross gear L
Select gear
Gear B
Gear C
Pulley gear
Assembly and Configuration Diagram

MX-J270V
1-18
Fig.23
[Caution] To retassemble the cylinder gear, etc.with the
cam unit (cam gear and cans R1/R2 assembly),
gear unit and drive unit, align the position of the
pawl "s" on the drive unit to that o f the notch
on the cam gear r.Then, make sure that the
gear unit is engaged by turning the cam gear r
(See Fig. 24).
Removing the cams R1/R2 assembly
and cam gear r (See Fig.23)
1.
2.
3.
4.
Remove the slit washer fixing the cams R1 and R2
assembly.
By removing the two pawls "x" fixing the cam R1,
separate R2 from R1.
Remove the slit washer fixing the cam gear r.
Pull out the cam gear r from the C.G. base assembly.
Removing the C.G. base assembly
(See Fig.23 and 24)
Remove the three screws K retaining the C.G. base
assembly.
Fig.24
K
Slit washer
Pawl
Cam R2
Slit washer
Cam gear r
Cam switch board
C.G. base assembly
Cam R1
Pawl
Cam gear r
Notch
Cylinder
gear
Gear bracket
Cam R1, R2 assembly
Gear unit
Drive unit
s
Pawl
xx

MX-J270V
1-19
< Cassette mechanism section >
Removing the playback, recording and eraser
heads (See Fig.1~3)
1.While shifting the trigger arms seen on the right
side of the head mount in the arrow direction,turn
the flywheel R in counterclockwise direction until
the head mount has gone out with a click
(See Fig. 1).
2.When the flywheel R is rotated in counterclockwise
direction, the playback head will be turned in
counterclockwise direction from the position in
Fig.2 to that in Fig.3.
3. At this position, disconnect the flexible P.C.board
(outgoing from the playback head) from the
connector CN301 on the head amp.and mechanism
control P.C. board.
4. After dismounting the FPC holder,remove the
flexible P.C.board.
5. Remove the flexible P.C.board from the chassis
base.
6. Remove the spring "a" from behind the playback
head.
7. Loosen the reversing azimuth screw retaining the
playback head.
8.Take out the playback head from the front of the
head mount.
9.The recording and eraser heads should also be
removed similarly according to Steps 1~8 above.
Reassembling the playback, recording
and eraser heads (See Fig.2,3)
1. Reassemble the playback head from the front of
the head mount to the position as shown in Fig.3.
2. Fix the reversing azimuth screw.
3. Set the spring a from behind the playback head.
4. Attach the flexible P.C.board to the chassis base,
and fix it with the FPC holder as shown in Fig.3.
5.The recording and eraser heads should also be
reassembled similarly according to Steps 1~4
above.
Cassette mechanism
Flywheel R
Trigger armHead mount
(Mechanism A side)
(Mechanism A side)
Playback/Recording &
eraser head
Flexible
P.C.board
Spring "a"
Trigger arm
Head amplifier & mechanism
control P.C. board Flywheel R
CN301
Playback head Reversing azimuth
screw
Head
mount
Flexible
P.C.board
Spring "a"
FPC holder Head amplifier &
mechanism control
P.C. board
CN302
(Mechanism B side)
Fig.1
Fig.2
Fig.3

MX-J270V
1-20
Removing the head amp.and mechanism
control P.C.board (See Fig. 4)
1.Remove the cassette mechanism assembly.
2.After turning over the cassette mechanism
assembly, remove the five screws "A" retaining
the head amp. and mechanism control P.C.
board
3.Disconnect the connectors CN303 and CN304
on the P.C.Board and the connectors CN1 on
both the right and left side reel pulse
P.C.Boards.
4.When necessary, remove the 4pin parallel
wire soldered to the main motor
Removing the capstan motor assembly
1.Remove the six screws "B" retaining capstan
motor assembly (See Fig.5).
2.While raising the capstan motor, remove the
capstan belts A and B respectively from the
motor pulley (See Fig.6).
Caution 1: Be sure to handle the capstan
belts so carefully that these belts
will not be stained by grease and
other foreign matter. Moreover,
these belts should be hand while
referring to the capstan belt
hanging method.
Flexible
board Flexible
board
CN302 CN301
CN304 CN303
Head amplifier &
mechanism control board
Capstan motor
assembly
Capstan
belt A Capstan belt B Motor pulley
Capstan
belt A Capstan belt B
Capstan motor
AAA
AA
BB
BBBB
Fig.4
Fig.5
Fig.7 Fig.6