JVC UX-J55MD Service Manual

MB124200311

SERVICE MANUAL

MICRO COMPONENT MD SYSTEM

UX-J55MD

Area suffix

UB -------------------- Hong Kong

123

456

789

10 0 +10

DISC UP

TITLE/EDIT

GROUP SKIP GROUP SKIP

GROUP TITLE

DISC DOWN

CD MD TAPE

GROUP REC

REC

ON/OFF

TIME

SPEED

TAPE

MD&TAPE

REC

CLOCK/

PLAY

TIMER

REPEAT

MODE

SLEEP

BASS/

DIMMER

A.STANDBY

TREBLE

BEEP

SHIFT AHB PRO

LP:

RM-SUXJ55MDU REMOTE CONTROL

STANDBY/ON

DISP/CHARA

CANCEL

ENTER

TITLE SEARCH

FM/AM

CD REC

MODE

VOLUME

STANDBY/ON

AUTO REVERSE

MICRO COMPONENT MD SYSTEM UX-J55MD

DISC LOADING MECHANISM

DOWN

DISC

SELECT

SET

/AUX

REV.

CD/MD TAPE

CD1 CD2 CD3 CD4 CD5

5-CD CHANGER, PLAY&EXCHANGE

PHONES

5-CD

MD REC

AUX/DVD

FM/AM

REV.MODE

VOLUME

AHB PRO

TABLE OF CONTENTS

1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

2 SPECIFIC SERVICE INSTRUCTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-43

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-47

No.MB124

2003/11

SPECIFICATION

Amplifier Output Power (IEC 268-3) 40 W (20 W + 20 W) at 4 & (MAX.), 30 W (15 W + 15 W) at 4 & (10 % THD)

Audio input sensitivity/ Impedance (at 1 kHz)

Speakers/Impedence 4 Ω - 16Ω

Tuner FM tuning range 87.50 MHz 108.00 MHz

AM tuning range 531 kHz 1 710 kHz (at 9 kHz channel spacing)

CD player CD Capacity 5 CDs

Dynamic range 87 dB Signal-to-noise ratio 90 dB Wow and flutter Immeasurable

MD recorder Audio playing system MiniDisc digital audio system

Recording system Magneto-optical overwrite system Reading system Non-contact, semiconductor laser pickup (lamda=780 nm) Error correction system CIRC (Cross Interleave Reed Solomon Code) Recording/Playback time

(when using a 80-minute MD)

Sampling frequency 44.1 kHz Audio compression system ATRAC (Adaptive TRansform Acoustic Coding)/ATRAC3 (MDLP)

Cassette deck Frequency response Normal (type I):60 Hz 14 000 Hz

Wow and flutter 0.15 % (WRMS)

General Power requirement AC 230 V~, 50 Hz

Power consumption: At operation 50 W On standby 11.8 W, 0.9 W (in Power Save) Dimensions (approx.) 175 mm × 239.5 mm × 378 mm (W/H/D) Mass (approx.) 7.8 kg

Analog input:AUX/DVD 400 mV/47 kΩ (at "Input LEVEL 1")

200 mV/47 kΩ (at "Input LEVEL 2")

530 kHz 1 710 kHz (at 10 kHz channel spacing)

SP:80 minutes LP2:160 minutes LP4:320 minutes

Design and specifications are subject to change without notice.

1-2 (No.MB124)

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 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, 1,000Ω per volt or more sensitivity in the following manner. Connect a 1,500Ω 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.MB124)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

Conductive material (conductive sheet) or iron palate

(3) Handling the optical pickup

• In order to maintain quality during transport and before installation, both sides of the laser diode on the re placement optical 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.

1-4 (No.MB124)

1.7 Attention when pickup unit is removed

1.7.1 Attention when MD pickup unit is removed *Please refer to "Disassembly method" in the text.

(1) Apply solder to short land section before the flexible wire is disconnected from the connector CN610

board. (If the flexible wire is disconnected without applying solder, the MD pickup may be destroyed by static electricity.)

(2) In the assembly, be sure to remove solder from the short land section after connecting the flexible wire.

MD servo control board

on the MD servo control

CN310

Short land section

Flexible wire

MD pickup

1.7.2 Attention when CD pickup unit is removed *Please refer to "Disassembly method" in the text.

(1) Apply solder to short land section before the card wire is disconnected from the connector on the flexibl e board.

(If the card wire is disconnected without applying solder, the CD pickup may be destroyed by static electricity.)

(2) In the assembly, be sure to remove solder from the short land section after connecting the card wire.

Card wire

Short land section

CD pickup

Flexible board

(No.MB124)1-5

1.8 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 laser

radiation and is equipped with safety switches which

prevent 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.

Please use enough caution not to see the beam directly or touch it in case of an adjustment or operation check.

REPRODUCTION AND POSITION OF LABEL and PRINT

WARNING LABEL and PRINT

CLASS 1 LASER PRODUCT LABEL

CLASS 1 LASER PRODUCT

LASER CAUTION LABEL

E406507-

1-6 (No.MB124)

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.

(No.MB124)1-7

SECTION 3

DISASSEMBLY

3.1 Main body section

3.1.1 Removing the metal cover (See Figs.1 to 3)

(1) From the back side of the main body, remove the six

screws A attaching the metal cover. (See Fig.1.)

(2) From the both sides of the main body, remove the two

screws B attaching the metal cover. (See Figs.2 and 3.)

(3) Remove the metal cover in the direction of the arrow while

extending the lower sections of the metal cover. (See Figs.2 and 3.)

Metal cove

Fig.1

Metal cover

Fig.2

Metal cover

1-8 (No.MB124)

Fig.3

3.1.2 Removing the front panel assembly

(See Figs.4 to 6)

• Remove the metal cover.

(1) From the left side of the main body, remove the screw C

attaching the earth wire. (See Fig.4.)

(2) Disconnect the wire from the connectors CN906

power supply board. (See Fig.4.)

(3) From the top side of the main body, remove the two screws

D attaching the front panel assembly. (See Fig.5.)

(4) From the bottom side of the main body remove the two

screws E attaching the front panel assembly. (See Fig.6.)

(5) Release the two hooks a and hook b from the both and

bottom sides of the front panel assembly, and draw out the front panel assembly in the direction of the arrow. (See Fig.6.)

(6) From the top side of the main bo dy, disconnect the card

wires from the connectors (CN706 board. (See Fig.5.)

(7) Remove the front panel assembly from the main body.

Reference:

When attaching the front panel assembly, fit the micon board to the notch c on the back side of the front panel assembly. (See Fig.5.)

, CN708) on the micon

on the

CN906

Power supply board

Front panel assembly

Spacer

Fig.4

Micon board

CN706

Notch c

CN708

Micon board

Front panel assembly

Fig.5

Hook a

Hook b

Hook a

Front panel assembly

Fig.6

(No.MB124)1-9

3.1.3 Removing the rear panel

(See Fig.7)

• Remove the metal cover.

(1) From the back side of the main body, remove the five

screws F attaching the rear panel. (2) Remove the screw G attaching the rear cover. (3) Remove the rear cover from the chassis wh ile extending

the sections d of the rear panel in the direction of the arrow.

Reference:

When removing the rear cover, remove the screw G and two screws G’.

Rear panel

3.1.4 Removing the cassette board (See Fig.8)

• Remove the metal cover.

(1) From the left side of the main body, disconn ect the card

wire from the connector CN32 (2) Remove the two screws H attaching the cassette board. (3) Release the joint section e toward this side and remove the

joint section f in the direction of the arrow. (4) From the forward side of the cassette board, disconnect

the wire from the connector CN31

3.1.5 Removing the power supply board (See Fig.9)

• Remove the metal cover.

(1) From the left side of the main body, remove the screw J

and screw J’attaching the power supply board.

(2) Disconnect the conne ctors (CN901

supply board toward this side.

(3) From the forward side of the power supply board,

disconnect the wires from the connectors (CN902

CN904

Reference:

When attaching the screw J’ attach the primary protector with it.

3.1.6 Removing the tuner (See Fig.9)

• Remove the metal cover.

(1) From the left side of the main body, disconn ect the card

wire from the connector CN1

(2) From the back side of the main body, remove the two

screws K attaching the tuner.

Reference:

After attaching the tuner, put the card wire on the section g of the primary protector.

on the cassette board.

, CN905) on the power

, CN903,

on the tuner.

Card wire

CN32

Cassette board

CN31

Tuner

CN903

CN904

Joint f

Card wire

Fig.7

Fig.8

Power supply board

CN1

CN905

Fig.9

Rear cover

Joint e

CN901

CN902

Primary protecto

1-10 (No.MB124)

3.1.7 Removing the micon board

(See Figs.10 and 11)

• Remove the metal cover, front panel assembly and rear panel.

(1) From the top side of the main bo dy, disconnect the card

wires from the connectors (CN703

) on the micon board. (See Fig.10.)

CN714

(2) Disconnect the wire from the connector on the load board

of the cassette mechanism assembly. (See Fig.10.)

(3) Disconnect the wire from the connector CN701

micon board. (See Fig.10.)

Reference:

When reassembling, fix the wire with wire clamp after connecting the wire to the connector CN701 micon board. (See Fig.10.)

(4) From the right side of the main body, remove the three

screws L attaching the micon board. (See Fig.11.)

(5) Disconnect the connectors (CN711

board toward this side. (See Fig.11.)

(6) From the forward side of the micon board, disconnect the

card wires from the connectors CN709

, CN704, CN710,

on the

, CN713) on the micon

. (See Fig.11.)

Cassette mechanism assembly

CN704

Micon board

CN710

CN703

Load board

Fig.10

Connector

CN714

Wire clamp

Micon board

CN701

3.1.8 Removing the power amplifier board

(See Fig.12)

• Remove the metal cover, front panel assembly, rear panel,

power supply board and micon board. (1) From the top side of the main body, remove the wire clamp

and tie band fixing the wire 1.

(2) Remove the three screws M and screw N attaching the

power amplifier board.

Reference:

• After attaching the power amplifier baord, pass the wire 1 through the section h of the power amplifier board and fix the wire 1 with the wire clamp and tie band.

• Pass the wire 2 and earth wire through section i of the power amplifier board.

• When attaching the screw N, attach the earth wire with it.

Wire 2

CN709

CN713 CN711

Fig.11

Earth wire

Power amplifier board

Tie band

Fig.12

Wire 1

Wire clamp

(No.MB124)1-11

3.1.9 Removing the heat sink (See Figs.13 and 14)

• Remove the metal cover, front panel assembly, rear panel,

power supply board, micon board and power amplifier board. (1) From the reverse side of the power amplifier board, bend

the claw j of the heat sink in the direction of the arrow. (See Fig.13.)

(2) From the side of the power amplifier board, remove the

three screws P attaching the heat sink.

(3) Disengage the joints k and remove the heat sink in the

direction of the arrow. (See Fig.14.)

Power amplifier board

Fig.13

Joints k

Claw j

Heat sink

3.1.10 Removing the power transformer (See Fig.15)

• Remove the metal cover, front panel assembly, rear panel,

power supply board, micon board and power amplifier board. (1) From the top side of the main body, remove the wire clamp

fixing the wire. (2) Remove the tie band. (3) Remove the four screws Q attaching the power transformer

and take out the power transformer from the main body.

Power transformer

Tie band

Power amplifier board

Fig.14

Wire clamps

Wire clamp

Fig.15

1-12 (No.MB124)

3.1.11 Removing the cassette mechanism assembly (See Fig.16)

• Remove the metal cover and front panel assembly.

(1) From the top side of the main bod y, disconnect the wire

and card wire from the connectors (CN31 cassette board.

(2) Disconnect the card wire from the connector CN704

micon board.

(3) Disconnect the wire from the connector on the load board

of the cassette mechanism assembly.

(4) Remove the four screws R attaching the cassette

mechanism assembly, and take out the cassette mechanism assembly from the main body.

Reference:

After reassembling, put the card wire through the section m of the mechanism protector.

3.1.12 Removing the MD mechanism assembly (See Figs.17 and 18.)

• Remove the metal cover, front panel assembly and micon

board. (1) From the right side of the main body, disconne ct the card

wire from the connector CN652 board. (See Fig.17.)

Reference:

After reassembling, fix the card wire with the spacer.

(2) From the both sides of the main body, remove the four

screws S attaching the MD mechanism assembly. (See Figs.17 and 18.)

(3) Remove the MD mechanism assembly from the bosses n

and p, and take out it in the direction of the arrow. (See Figs.17 and 18.)

on the CD servo control

, CN32) on the

on the

Cassette mechanism assembly

CN31

Insulator

MD mechanism assembly

CN704

Fig.16

Spacer

Cassette board

CN32

Micon board

Connector

Load board

Boss n

CD servo control board

Fig.17

Boss p

Fig.18

CN652

MD mechanism assembly

Main chassis

(No.MB124)1-13

3.1.13 Removing the CD changer mechanism assembly (See Figs.19 to 22.)

• Remove the metal cover and front panel assembly.

(1) From the right side of the main body, disconnect the card

wires from the connectors (CN651, CN652) on the CD servo control board. (See Fig.19.)

(2) From the front and bottom sides of the main body, remove

the two screws T and two screws U attaching the CD bracket(F). (See Fig.20.)

(3) From the top side of the main body, remove the two screws

V attaching the CD changer mechanism assembly. (See Fig.21.)

Reference:

When attaching the CD changer mechanism assembly, align the bosses q and r of the bottom chassis in the hole of the CD changer mechanism assembly. (See Fig.21.)

(4) Take out the CD changer mechanism assembly in the

direction of the arrow. (See Fig.19.)

Note:

When take out the CD changer mechanism assembly, be careful not to damage the several parts on the C D servo control board.

(5) From the back side of the CD changer mechanism

assembly, remove the two screws W attaching the CD bracket(R). (See Fig.22.)

CD changer mechanism assembly

Fig.20

CD changer mechanism assembly

CD bracket (F)

Boss q

CN652

CN651

CD servo control board

Fig.19

Bottom chassis

Boss r

Fig.21

CD bracket (R)

Fig.22

1-14 (No.MB124)

3.1.14 Removing the switch board

(See Figs.23 and 24)

• Remove the metal cover and front panel assembly.

(1) From the front side the front panel assemb ly, pull out the

volume knob. (See Fig.23.)

(2) From the inside of the front panel assembly, remove the six

screws X attaching the switch board. (See Fig.24.)

(3) Take out the switch board from the front panel assembly

and disconnect the card wire from the connector CN510 the forward side. (See Fig.24.)

Front panel assembly

Volume knob

Fig.23

3.1.15 Removing the back light board

(See Figs.24 and 25)

• Remove the metal cover and front panel assembly.

(1) From the inside of the front panel assembly, remove the six

screws Y attaching the back light board. (See Fig.24.)

(2) Take out the back light board from the front panel assembly

and disconnect the card wires from the connectors (CN561

Reference:

Remove the stay bracket as required. (See Fig.25.)

, CN562) on the forward side. (See Fig.24.)

Back light board

CN561

Stay bracket

Card wire

CN510

Front panel assembly

Fig.24

LED lens

Front panel assembly

CN562

Card wire

Switch board

Lens holder

Stay bracket

Fig.25

(No.MB124)1-15

+ 35 hidden pages