JVC MXGA-8-UM Service manual

MB080200312
SERVICE MANUAL
COMPACT COMPONENT SYSTEM
MX-GA8
CD
3
2
CD
CD
1
STANDBY
STANDBY/ON
DISC CHANGE
REC START
COMPACT COMPONENT SYSTEM MX-GA8
ROCK
/ STOP
CD REC
P
PO
START
DUBBING
CLASSIC
DISPLAY
PHONES
SOUND TURBO
SUBWOOFER LEVEL
U
L
M
O
E
V
M
D
O
N
U
D
E
O
S
TUNING
TUNING
BEEP
REPEAT
NCE
DA
PROGRAM
HALL
RANDOM
STADIUM
CLOCK / TIMER
SET
PRESET
CANCEL / DEMO
TAPE A / B
EJECTEJECT
SP-MXGA8 SP-MXGA8CA-MXGA8
Area Suffix
JW ------- Mexico,Panama
TABLE OF CONTENTS
2 SPECIFIC SERVICE INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-24
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LIMITED
No.MB080
2004/1
SPECIFICATION
Amplifier section Output Power SUBWOOFERS 120 W per channel, min. RMS, driven into 6 at 63 Hz with no more
than 10% total harmonic distortion.
MAIN SPEAKERS 60 W per channel, min. RMS, driven into 4 at 1 kHz with no more
than 10% total harmonic distortion.
Audio input sensitivity/ Impedance (at 1 kHz, measured at MAIN SPEAKERS)
Speakers/Impedance Subwoofers 6 - 16
Tuner FM tuning range 87.50 MHz - 108.00 MHz
AM tuning range 530 kHz - 1 710 kHz
CD player CD Capacity 3 CDs
Dynamic range 85 dB Signal-to-noise ratio 85 dB
Cassette deck Frequency response
Normal (type I) Wow and flutter 0.1 5% (WRMS)
General Power requirement AC 120 V , 60 Hz
Power consumption 160 W (at operation)
Dimensions (approx.) 270 mm × 317 mm × 453 mm (W/H/D) Mass (approx.) 8.8 kg
Speaker section Type 3-way bass-reflex type
Speaker units Subwoofer 13.5 cm cone ×1
Power handling capacity Subwoofer 120 W
Impedance Subwoofer 6
Frequency range Subwoofer 30 Hz - 70 Hz
Sound pressure level Subwoofer 73 dB/W
Dimensions (approx.) 290 mm × 317 mm × 336 mm (W/H/D) Mass (approx.) 5.5 kg each
AUX 400 mV/50 k
Main speakers 4 - 8
50 Hz - 14 000 Hz
18 W (on standby)
Main Woofer 16 cm cone ×1 Tweeter 5 cm cone ×1
Main speaker 60 W
Main speaker 4
Main speaker 70 Hz - 20 000 Hz
·m
Main speaker 86 dB/W
·m
Design and specifications are subject to change without notice.
1-2 (No.MB080)
SECTION 1
PRECAUTION
1.1 Safety Precautions
(1) This design of th is product contains special hardw are 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 manufacturers 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 reassem­bling.
(5) Leakage shock hazard testing
After reassembling 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 outle t. Usin g 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 per volt or more sensitivity in the following manner. Connect a 1,500 10W resistor paralleled by a 0.15µF 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 each exposed metal part, particularly any exposed metal part having a return path to the chassis, and measure 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.).
AC VOLTMETER (Having 1000 ohms/volts, or more sensitivity)
0.15 F AC TYPE
Place this probe on
1500 10W
Good earth ground
1.2 Warning
(1) This equipment has been designed and manufactured to
meet international safety standards.
(2) It is the legal resp onsibility 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 compone nts are replaced
by approved parts.
(5) If mains voltage selector is provided, check setting for local
voltage.
1.3 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.
1.4 Critical parts for safety
In regard with component parts appearing on the silk-screen printed side (parts side) of the PWB diagrams, the parts that are printed over with black such as the resistor ( ), diode ( ) and ICP ( ) or identified by the " " mark nearby are critical for safety. When replacing them, be sure to use the parts of the same type and rating as specified by the manufacturer. (This regulation dose not Except the J and C version)
each exposed metal part.
(No.MB080)1-3
1.5 Preventing 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.
1.5.1 Grounding to prevent damage by static electricity
Static electricity in the work area can destroy the optical pickup (laser dio de) in devices such as CD players. Be careful to use proper grounding in the area where repairs are being performed.
(1) Ground the workbench
Ground the workbench by laying conductive material (such as a conductive sh eet) or an iron plate over it before placing the traverse unit (optical pickup) on it.
(2) Ground yourself
Use an anti-static wrist strap to release any static electricity built up in your body.
(caption) Anti-static wrist strap
1M
Conductive material (conductive sheet) or iron palate
(3) Handling the optical pickup
• In order to maintain quality during tra nsport and before instal lation, both sides of the laser diode on the replacement optica l pickup are shorted. After replacement, return the shorted parts to their original condition. (Refer to the text.)
• 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.
1.6 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) I t is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.
1.7 Attention when traverse unit is decomposed *Please refer to "Disassembly method" in the text for the CD pickup unit.
• Apply solder to the short land section s before the flexible wire is disconnected from the connector on the CD servo board. (If the flexible wire is disconnected without applying solder, the CD pickup may be destroyed by static electricity.)
• In the assembly, be sure to remove solder from the short land sections after connecting the flexible wire.
1-4 (No.MB080)
Card wire
Picup unit connector
Soldering
CD changer unit
CD changer mechanism
Card wire
Picup unit connector
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.
(No.MB080)1-5
SECTION 3
A
DISASSEMBLY
3.1 Main body
3.1.1 Removing the metal cover
(See Fig. 1)
(1) Remove the three screws A attaching the metal cover on
the back of the body.
(2) Remove the six screws B attaching the metal cover on both
sides of the body.
(3) Remove the metal cover from the bod y by lifting the rear
part of the cover.
ONE POINT
How to eject the CD tray manually (see fig. 2)
Turn the loading pulley gear at the bottom of the CD changer unit as shown in Fig.2 and draw the CD tray toward the front.
Metal cover
B
(both sides)
Fig.1
Loading pulley gear (See <CD changer unit>fig.1)
3.1.2 Removing the CD tray fitting
(See Fig. 3)
• Prior to performing the following procedure, eject the CD tray. (1) After drawing the lower part of the tray fitting toward the
front, remove the five claws. Then, while moving the tray fit­ting upward, remove it.
Fig.2
Joint
CD tray fitting
Claw
Fig.3
1-6 (No.MB080)
3.1.3 Removing the CD changer unit
A
(See Fig. 4 to 7)
• Prior to performing the following procedure, remove the metal cover and CD tray fitting. (1) Remove the card wire attached to CD changer unit on the
adhesion tape.
(2) Disconnect the card wire from the connector CW105
CD board.
(3) Disconnect the harness from the connector CW104
main board.
(4) Remove the two screws C attaching the CD changer unit to
the rear panel.
(5) Remove the two screws D attaching the CD changer unit to
both sides of the front panel assembly.
(6) Draw the CD changer unit upward from behind while pull-
ing the rear panel outward.
on the
on the
dhesion tape
CW105
CD changer unit
Card wire
Fig.4
CD board
CD changer unit
CW104
Front panel
assembly
D
(both sides)
Main board
Fig.5
C
Rear panel
Fig.6
CD changer unit
Rear panel
Fig.7
(No.MB080)1-7
3.1.4 Removing the front panel assembly (See Fig. 8 to 10)
• Prior to performing the follow ing procedure, re move the metal
cover and CD changer unit. (1) Disconnect the card wire from the connector CW101 on the
main board.
(2) Disconnect the harness from the connector CW108
CW109 and CW110 on the main board. (3) Remove the screw E fixiing the lug wire. (4) Remove the two screws F attaching the front panel assem-
bly to both sides of the body. (5) Remove the screw G attaching the main board to the front
panel assembly. (6) Remove the screw H attaching the front panel assembly to
bottom of the body. (7) Release the two joints1 a nd two joints2, and detach the
front panel assembly toward the front.
,
Front panel
assembly
Joint1 (both sides)
(both sides)
F
CW101
CW109
CW110
CW108
Fig.8
E
(fixing the lug wire)
Front panel assembly
Main board
ACW1
ACW2
Amp. board
Main board
H
G
Joint1 (both sides)
F
(both sides)
Fig.9
Joint2
Fig.10
1-8 (No.MB080)
3.1.5 Removing the heat sink & amp. Board (See Fig. 8, 11 and 12)
• Prior to performing the following procedure, remove the metal
cover and CD changer unit. (1) Disconnect the card wire from the connector ACW1
the harness from the connector ACW2
(2) Remove the four screws I attaching the heat sink cover to
the rear panel. Remove the heat sink cover.
(3) Remove the four screws J attaching the heat sink and two
screws K attaching the speaker terminal to the rear panel.
(4) After moving the heat sink upward, remove the claws. Then
pull out the heat sink & amp. board inward.
3.1.6 Removing the tuner board (See Fig. 12 and 13)
• Prior to performing the following procedure, remove the metal
cover. (1) Disconnect the card wire from the connector CON01
tuner board.
(2) Remove the two screws L attaching the tuner board to the
rear panel.
3.1.7 Removing the rear panel (See Fig. 12)
• Prior to performing the following procedure, remove the metal
cover, CD changer unit, heat sink & amp. board and tuner board. (1) Remove the screw M and three screws N attaching the rear
panel.
on the amp. board.
and
on the
Heat sink
J
Claws
Heat sink
cover
Rear panel
I
I
Fig.11
Rear panel
L
K
Speaker terminal
M
J
N
Main board
Fig.12
CON01
Rear panel
Tuner board
Fig.13
(No.MB080)1-9
3.1.8 Removing the main board (See Fig. 14)
• Prior to performing the follow ing procedure, re move the metal
cover, CD changer unit and rear panel. (1) Disconnect the card wire from the co nnector CW101 and
the harness from the connector CW108
on the main board.
CW110
(2) Disconnect the harness from the con nector PCW1 on the
fuse board.
(3) Remove the screw G attaching the main board to the front
panel assembly. (See Fig.9)
(4) Remove the two screws O attaching the heat sink to the
bottom chassis.
3.1.9 Removing the power cord (See Fig. 14)
• Prior to performing the follow ing procedure, re move the metal
cover, CD changer unit and rear panel. (1) Disconnect the power cord from the co nnector PW101
the power supply board and pull up the power cord stopper upward.
3.1.10 Removing the power ICs (See Fig. 15 and 16)
• Prior to performing the follow ing procedure, re move the metal
cover, CD changer unit and heat sink & amp. board. (1) Unsolder the power ICs solder points. (2) Remove the four screws P attaching the power ICs to the
heat sink.
, CW109 and
on
CW108
Fuse board
PCW1
PW101
Power cord
Power cord
stopper
Bottom chassis
Power ICs solder point
Fig.14
Heat sink
CW101
CW109
CW110
Main board
Heat sink
O
Power supply
board
3.1.11 Removing the power transformer (See Fig. 17)
• Prior to performing the follow ing procedure, re move the metal
cover, CD changer unit and heat sink & amp. board. (1) Disconnect the power cord from the co nnector PW101
the power supply board.
(2) Disconnect the harness from the con nector PCW1
fuse board.
(3) Remove the four screws Q attaching the power transformer
on the bottom chassis.
on
on the
Q
Fig.15
P
Fig.16
Power transformer
Amp. board (reverse side)
Heat sink
Amp. board
Fuse board
PCW1
Power supply
board
1-10 (No.MB080)
Bottom chassis
PW101
Fig.17
3.2 Front panel assembly
• Prior to performing the following procedure, remove the front
panel assembly.
3.2.1 Removing the CD switch board
(See Fig. 1)
(1) Disconnect the card wire from the connector UCW03
the CD switch board.
(2) Remove the four screws A attaching the CD switch board.
3.2.2 Removing the front board
(See Fig. 1 and 2)
(1) Pull out the sound mode knob, volume kno b, and preset
knob from the front side of front panel assembly.
(2) Disconnect the card wire from the connector UCW02
the front board and the connector on the mecha. board. (3) Remove the fourteen screws B attaching the front board. (4) Disconnect the card wire from the connector UCW01
the front board.
on
on
on
B
B
Connector
Mecha.
board
A
CD switch board
UCW03
Front board
UCW02
UCW01
Fig.1
Sound mode knob Volume knob
3.2.3 Removing the headphone jack board (See Fig. 3)
• Prior to performing the following procedure remove the front
board. (1) You can pull out the headphone jack board.
3.2.4 Removing the cassette mechanism assembly (See Fig. 3)
(1) Disconnect the card wire from the connector on the mecha.
board.
(2) Remove the six screws C attaching the cassette mecha-
nism assembly.
Connector
C
Mecha.
board
Preset knob
Fig.2
Headphone
jack board
C
C
(fixing the lug wire)
Fig.3
Cassette mechanism
assembly
(No.MB080)1-11
3.3 CD changer unit
• Prior to performing the following procedure, remove the CD changer unit.
3.3.1 Removing the CD tray
(See Fig. 1 and 2)
(1) Turn the black loading pulley gear on the under side of the
CD changer unit in the direction of the arrow and draw the CD tray toward the front until it stops.
(2) Disconnect the card wire from connector CW103
board.
(3) Push down the two tray stoppers marked a and pull out the
CD tray.
on the CD
Loading pulley
gear
CD tray
CD board
CW103
Fig.1
a (Tray stopper)
3.3.2 Reinstall the CD tray
(See Fig. 3 and 4)
(1) Align the gear-cam with the gear-tray as shown fig.3, then
mount the CD tray.
(2) When assembling the CD tray, take extreme care not en-
gage with gear - synchro.
Gear-cam
Gear-tray
Gear-cam
Gear-convert
timing point
Gear-tray
CD tray
a
(Tray stopper)
CW103 (on the CD board)
Fig.2
Gear-synchro
CD tray
Fig.4
Gear-convert
1-12 (No.MB080)
Gear-tray
Fig.3
3.3.3 Removing the sensor board
r
(See Fig. 5)
• Prior to performing the following procedure, remove the CD tray. (1) Remove the screw A attaching the sensor board on the CD
tray. (2) Remove the sensor board releasing the two tabs a. (3) Disconnect the harness from the connector CW1
sensor board.
on the
A
3.3.4 Removing the turn tray motor (See Fig. 6 and 7)
• Prior to performing the following procedure, remove the CD
tray and sensor board. (1) Remove the screw B attaching the turn tray. Detach the
turn tray from the base tray.
(2) Pull outward the tab b attaching the turn tray motor on the
base tray and detach the turn tray motor.
CW1
Tab a
Sensor board
Fig.5
Turn tray
B
Base tray
Fig.6
Turn tray moto
Tab b
Fig.7
(No.MB080)1-13
3.3.5 Removing the belt, the CD board and the switch board (See Fig. 8 and 9)
• Prior to performing the following procedure, remove the CD
tray. (1) Detach the belt from the pulley on the upper side of the CD
changer unit (Do not stain the belt with grease).
(2) Disconnect the card wire from the pickup unit connector on
the under side of the CD changer unit.
Attention :
Solder is put up before the card wire is removed from the pick-up unit connector on the CD mechanism assembly. (When the card wire is removed without putting up sol­der, the CD pick-up unit assembly might destroy.)
(3) Disconnect the motor wire harness from connector on the
CD board.
(4) Remove the screw C attaching the switch board and re-
lease the two tabs e attaching the switch board outward and detach the switch board.
(5) Remove the two screws D attaching the CD board. First re-
lease the two tabs f and two tabs g attaching the motor, then release the CD board.
If the tabs f and g are hard to release, it is recommendable
to unsolder the two soldered parts on the motor terminal of the CD board.
Tabs e
C
CD changer unit
Fig.8
CD board
D
Tabs g
Soldered parts
Belt
Motor
Tabs f
Switch board
CW3
Soldering
CD mechanism board
motor connecter
Pickup unit connector
Card wire
Picup unit connector
Fig.9
1-14 (No.MB080)
3.3.6 Removing the CD mechanism holder assembly
(mechanism included) (See Fig. 10 to 13)
(1) Disconnect the harness from connector on the CD mecha-
nism board in the CD mechanism assembly on the under side of the CD changer unit. Disconnect the card wire from the pickup unit connector.
Attention :
Solder is put up before the card wire is removed from the pick-up unit connector on the CD mechanism assembly. (Refer to Fig.9) (When the card wire is removed without putting up solder, the CD pick-up unit assembly might destroy.)
(2) Remove the screw E attaching the shaft on the right side of
the CD mechanism holder assembly. Pull outward the stopper fixing the shaft on the left side and remove the CD mechanism holder assembly from behind in the direction of the arrow y.
(3) Turn the CD mechanism holder a ssembly half around the
lift up slide shaft h of the CD mechanism holder assembly until the turn table is reversed, and pull out the CD mecha­nism holder assembly.
Motor connecter
CD mechanism holder assembly
Fig.11
Lift up slide shaft
E
Stopper
n
y
CD changer unit
Pickup unit connector
CD mechanism holder assembly
Fig.12
Lift up slide shaft
CD mechanism holder assembly
Fig.10
CD mechanism holder assembly
Fig.13
(No.MB080)1-15
3.4 CD mechanism section
A
• Removing the CD mechanism holder from the CD chager unit.
(Refer to "Removing the CD mechanism holder assembly" )
3.4.1 Removing the pickup unit (See Fig. 1)
(1) Removing the cut washer on the feed gear sleeve and pull
out the feed gear. (2) Remove the two screws A fixing the pickup shaft. (3) Removing the pickup unit.
3.4.2 Removing the motor board (See Fig. 2)
(1) Unsolder the motor terminal on the motor board. (2) Remove the moter board.
3.4.3 Removing the feed motor (See Fig. 1)
(1) Remove the two motor fixing screws at B and removing the
feed motor.
3.4.4 Removing the spindle motor
• The spindle motor cannot be removed as a single unit.
• When removing the spindle motor, change the chasis and turn-
table together as aunit.
A
Motor board
Shutter
Cut washer
B
Fig.1
Unsolder
Pickup unit
Feed motor
Shaft
Feed Gear
Spindle motor
Unsolder
Fig.2
1-16 (No.MB080)
3.5 Cassette mechanism section
r
• Prior to performing the following p rocedure, remove the cas-
sette mechanism assembly.
3.5.1 Removing the R/P head.
(See Fig. 1 and 2)
(1) Remove the screw A on the right side of the R/P head. (2) Remove the screw B on the left side of the R/P head.
3.5.2 Remove the erase head.
(See Fig. 1)
(1) Remove the screw C fixing the erase head.
R/P Head
Pinch rolle
3.5.3 Remove the pinch roller.
(See Fig. 3)
(1) Pull out the pinch roller stopper. (2) Pull out the pinch roller.
E. Head
Spring
ABC
Fig.1
B
R/P Head
Fig.2
Pinch roller
stopper
A
Pinch roller
Fig.3
(No.MB080)1-17
3.5.4 Removing the motor
r
r
(See Fig. 4 to 6)
(1) Slide the plastic cover in the direction of the arrow, and re-
move the three claws. Then remove the plastic cover.
(2) Remove the two screws D fixing the motor. Be careful to
grease's splash when the drive belt comes off.
(3) Unsolder the motor terminal.
3.5.5 Removing the mechanism board (See Fig. 5)
(1) Unsolder the four solder parts a and the four solder parts b. (2) Remove the two screws E attaching the mecha. board.
Solder part
Motor
b
terminal Solder part
E E
a
Solder part
a
Mecha. board
D
Claw
Fig.4
3.5.6 Removing the flywheel (See Fig. 7 and 9)
(1) Remove the cut-washer at c from the capstan shaft, then
remove the flywheel. When reassembling the flywheel, be sure to use new washers as they cannot be reused.
Plastic cove
Drive belt
Drive belt
Motor
Drive belt
Fig.5
Moto
Drive belt
Fig.6
Fig.7
Capstan
washer
Flywheel
FR belt
Fig.8
c
Sleeve
Washer
FR belt
Fig.9
1-18 (No.MB080)
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