JVC UX-A70MD Service Manual

SERVICE MANUAL

MICRO COMPONENT MD SYSTEM

UX-A70MD

DEF

ABCMARK

21 3

GHI JKL MNO

54 6

PQRS TUV WXYZ

+10

Contents

Safety precautions Preventing static electricity Important for laser products Disassembly method Main adjustment Flow of functional operation until TOC read (CD) Flow of functional operation until TOC read (MD)

1-2 1-3 1-5 1-6 1-28

1-32

1-33

COMPACT

DIGITAL AUDIO

Area Suffix

UB US UT UF UJ

Maintenance of laser pickup Replacement of laser pickup Maintenance of MD pickup Procedures of changing the MD pickup Description of major ICs

Hong Kong

Singapore

Taiwan

China

U.S.Military

1-34 1-34 1-35

1-35 1-36~56

This service manual is printed on 100% recycled paper.

No.20901

1-1

Jan. 2001

UX-A70MD

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 proper ty damage resulting therefrom.

3. Many electrical and mechanical par ts 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 or iginal 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, par ticularly 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.).

0.15 F AC TYPE

1500 10W

Good earth ground

AC VOLTMETER (Having 1000 ohms/volts, or more sensitivity)

Place this probe on each exposed metal part.

1-2

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.

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.

UX-A70MD

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.

1.1. Grounding to prevent damage by static electricity

Static electricity in the work area can destroy the optical pickup (laser diode) in devices such as DVD players. Be careful to use proper grounding in the area where repairs are being performed.

1.1.1. Ground the workbench

1. 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.

1.1.2. Ground yourself

1. 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 plate

1.1.3. 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.

1.2. 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

1-3

UX-A70MD

MAIN board

CN451

CN321

CD SERVO board

Pickup

Soldering part b

1.3. Cautions on removing the CD traverse unit

* For removing the CD traverse unit in detail, refer to the "Adjustment Method" section of this manual.

1. Before disconnecting the flexible wire from the connector CN601 on the CD SERVO board, solder the part shown in the figure below. (Note:If the flexible wire is disconnected from the CN601 without presoldering, it may cause breakdown of the CD pickup assembly.)

2. When reassembling the CD traverse unit, be sure to remove the solder from the soldered part after reconnecting the flexible wire to the CN601.

CD SERVO board

CN601

1-4

Soldering part

UX-A70MD

1-5

UX-A70MD

Disassembly method

Removing the rear cover

(See Fig.1 and 2)

Remove the nine screws A attaching the rear cover on the back of the body.

Remove the two screws B attaching the rear cover on the bottom of the body.

Unlock the speaker terminal and the antenna terminal, then remove the rear cover backward with releasing the hooks.

Removing the side panels

(See Fig.3 and 4)

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

Antenna terminal

Fig.1

Rear cover

Speaker terminal

Rear cover

Remove each side panel backward while releasing the joints a.

Joints a

Fig.2

Joints a

1-6

Joints a

Side panel (Right)

Fig.4

Side panel (Left)

Joints a

Fig.3

UX-A70MD

Removing the top cover

(See Fig.5 and 6)

Prior to performing the following procedure, remove the rear cover and the side panels.

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

Release the joint b on each side of the body and remove the top cover backward and upward.

Removing the fan assembly (See Fig.6)

*Prior to performing the following procedure, remove the rear cover, the right and left side panels.

Remove the two screws D on the right side of the body and pull out the fan assembly sideward.

Joint b

Top cover

Tuner & function board

Fan assembly

Joint b

Fig.5

Top cover

Disconnect the wire from connector CN807 on the main board.

Removing the MD mechanism assembly unit (See Fig.7)

Prior to performing the following procedure, remove the rear cover, the side panels, the top cover and the fan assembly.

Disconnect the card wire from connector CN721 on the tuner & function board.

Remove the four screws D and the MD mechanism assembly backward and upward while pulling the front panel assembly forward.

CN807

CN721

Fig.6

MD mechanism assembly

Front panel assembly

Fig.7

1-7

UX-A70MD

Removing the tuner & function board

(See Fig.8)

Prior to performing the following procedure, remove the rear cover, the side panels and the top cover.

Disconnect the card wire from connector CN701, CN705, CN707, CN708 and CN721 on the tuner & function board on the right side of the body. Similarly, disconnect the harness from CN706.

CAUTION:

Disconnect connector CN711 and CN712 on the tuner & function board from CN801 and CN802 on the main board by pulling them outward.

Disconnect connector CN703 and CN704 on the tuner & function board from CN603 and CN604 on the CD servo board by pulling them upward.

For the card wire connected to CN707, disconnect it after performing the following procedure 2 and 3.

CN712

AC jack board

CN707

CN701

CN705

CN704

CN703

Fig.8

CN721

CN706

CN708

CN711

Removing the AC jack board (See Fig.9)

Prior to performing the following procedure, remove the rear cover and the right side panel.

Remove the screw E on the right side of the body and release the AC jack board from the two joints c.

Disconnect the harness from connector CN805 on the AC jack board.

Removing the antenna terminal board

(See Fig.10)

Prior to performing the following procedure, remove the rear cover and the left side panel.

Disconnect the card wire from connector CN1 on the left side of the body.

AC jack board

Fig.9

Joints c

Remove the screw F and release the antenna terminal board from the joint d upward.

1-8

CN1

Antenna terminal board

Fig.10

Joint d

Removing the front panel assembly unit

(See Fig.11 to 15)

Prior to performing the following procedure, remove the rear cover, the side panels, thetop cover, the MD mechanism assembly and the tuner & function board.

Disconnect the wire from connector CN804 and CN806 on the main board. Disconnectthe wire from W802 pin terminal.

Remove the two screws G on the bottom of the body.

Remove the lower screw H on each side of the body.

Release the lower joint e on each side of the body. Pull out the front panel assemblytoward the front.

CN804

CN806

W802

Front panel assembly

UX-A70MD

Main board

Front panel assembly

Fig.11

Front panel assembly

W802

Main board

Fig.12

Front panel assembly

Fig.13

Front panel assembly

Fig.15

Joint e

Fig.14

1-9

UX-A70MD

Removing the main board / heat sink

(See Fig.16 to 18)

Prior to performing the following procedure, remove the rear cover, the side panels, thetop cover, the MD mechanism assembly and the tuner & function board.

Disconnect the wire from connector CN803, CN804 and CN806 on the main boardrespectively. Disconnect the wire from W802 pin terminal.

2. Remove the screw I attaching the main board and the screw J attaching the wireterminal.

CAUTION:

Remove the three screws K on the heat sink bracket.

Remove the two screws L on the back of the main board.

When reasse mbling, fit the slots of the main board to the two bosses.

CN804

Heat sink

Main board

CN803

Fig.16

CN806

Bosse

Heat sink bracket

W802

CAUTION:

When removing the heat sink bracket, disengage the two joints d on theback of the main board.

Main board

Fig.17

Main borad

Joint d

1-10

Heat sink

Fig.18

Removing the CD mechanism assembly and the CD servo board

(See Fig.19 to 24)

Prior to performing the following procedure, remove the rear cover, the side panels, the top cover, the MD mechanism assembly, the tuner & function board, the AC jack board, the antenna terminal board, the front panel assembly and the main board.

Cut off the two tie band on the back of the CD mechanism assembly top cover.

Remove the screw M and the top cover.

Move the lever f in the direction of the arrow to draw the loading tray manually.

Remove the screw N on the CD tray and pull out the CD tray from the CD mechanism assembly.

Remove the two screws O attaching the clamper base on top of the CD mechanism assembly. Release the two joints g with the CD mechanism assembly and remove the clamper base upward.

Remove the three screws P attaching the CD mechanism assembly.

CD mechanism assembly

Loading tray

CD mechanism assembly

Clamper base

UX-A70MD

Tie band

Fig.19

Lever f

Fig.20

Remove the three screws Q attaching the CD servo board on the back of the CD mechanism assembly.

Disconnect the harness from connector P031 on the CD mechanism assembly. Disconnect the harness and the card wire from connector CN602 and CN601 on the CD servo control board respectively.

CD mechanism assembly

Joint g

Loading tray

Fig.21

CD mechanism assembly

Joint g

Clamper base

Fig.23

Fig.22

1-11

UX-A70MD

CD servo board

Removing the transformer assembly

(See Fig.19 and 25)

Cut off the two wire clamp on the back of the CD

mechanism assembly upper cover. Remove the screw M and the CD mechanism

assembly upper cover. Remove the four screws R attaching the transformer

assembly.

CN602

CN601

P031

CD mechanism board

Fig.24

Transformer assembly

Fig.25

1-12

UX-A70MD

Prior to performing the following procedure, remove the rear cover, the side panels, the top cover unit and the MD mechanism assembly unit.

Removing the MD mechanism assembly

(See Fig.26 to 28)

Remove the four screws S attaching the bracket (a) and (b) on both sides of the MD mechanism assembly unit.

Disconnect the card wire from connector CN521 on the MD mechanism board. Remove the MD mechanism assembly bottom cover downward.

MD mechanism assembly

Bracket (a)

Fig.26

MD mechanism assembly

CN521

Bracket (b)

Fig.27

MD mechanism assembly

MD mechanism assembly bottom cover

Fig.28

1-13

UX-A70MD

Prior to performing the following procedure,remove the rear cover,the side panels, the top cover, the MD mechanism assembly unit,the tuner & function board and the front panel assembly unit.

Removing the relay board (See Fig.29)

Disconnect the card wire from connector CN908 on the relay board respectively.

Remove the screw T attaching the relay board.

Removing the drive motor assembly

(See Fig.29 and 30)

Relay board

Drive motor assembly

Fig.29

Drive motor

Remove the four screws U attaching the drive motor assembly.

Remove the belt and the screw V attaching the drive motor.

Removing the headphone jack board

(See Fig.31)

Remove the six screws W attaching the bracket (c), and detach the headphone jack board.

Bracket (c)

Belt

Fig.30

1-14

Headphone jack board

Fig.31

UX-A70MD

Removing the key switch board / (d) board (See Fig.32 and 33)

Prior to performing the following procedure, remove the bracket (c).

Remove the three screws X attaching the key switch board.

Remove the spring g and the screw Y attaching the (d) board.

(d) board

Relay board

CN908

(d) board

Key switch board

Fig.32

Spring g

Fig.33

1-15

UX-A70MD

Removing the LCD board / sub board

(See Fig.32 and 34 to 37)

Disconnect the card wire from connector CN908 on the relay board on the back of thefront panel assembly.

Remove the four screws A’ attaching the CD / MD door cover on the front side of the frontpanel assembly. Remove the CD / MD door cover, then the LCD board unit.

Pull out the LCD lens from the four bosses on the LCD board unit.

Remove the LCD board and the lens cover in the direction of the arrow (The lens cover isattached with a double-sided tape).

Disconnect the sub board from connector CN913 on the LCD board.

CD / MD door cover

LCD board unit

Fig.34

Slot h

Lens cover

Fig.35

LCD lens

Slot h

LCD board

Fig.36

Sub board

1-16

Fig.37

CN913

LCD board

UX-A70MD

Removing the CD / MD door board

(See Fig.38 and 39)

Prior to performing the following procedure,remove the LCD board unit.

Remove the four screws B' attaching the two brackets (e). Remove the CD / MD door base and the two brackets (e).

Remove the screw C' attaching the CD / MD door board.

CD / MD door base

Brackets (e)

Fig.38

CD / MD door board

Fig.39

1-17

UX-A70MD

Disassembly method

Removing the main board

(See Fig.1 and 2)

Turn over the body and disconnect the card wire from connector CN408 and the flexible wire from CN407 on the main board.

Remove the two screws A attaching the main board. Slide the main board in the direction of the arrow to release the two joints a with the single flame.

Solder part b on the pickup in the body. Disconnect the flexible harness from connector CN321 and CN451 on the underside of the main board. Then remove the main board.

(Bottom)

Main board

CN408

CN407

Joint b Joint b

Fig.1

Main board

CN451

CN321

Removing the mechanism cover

(See Fig.3)

Remove the four screws B on both sides of the body.

Move the mechanism cover toward the front to disengage the front hook of the mechanism cover from the internal loading assembly (Joint c). Then remove the mechanism cover upward.

1-18

Fook

Joint c

Pickup

Fig.2

Fig.3

Solder part b

Mechanism cover

+ 39 hidden pages

JVC UX-A70MD Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Safety Precautions

Preventing static electricity

Disassembly method