JVC XM-PX70BU, XM-PX70PN, XM-PX70WT Service Manual

XM-PX70WT/BU/PN

SERVICE MANUAL

PORTABLE MINIDISC PLAYER

XM-PX70WT/BU/PN

UB Hong Kong

Area Suffix

Contents

Safety Precautions Attention when

MD pick up is exchanged

Disassembly method

Adjustment method

Maintenance of laser pickup Replacement of laser pickup Description of major ICs Attention when parts are exchanged

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1-3 1-4 1-9 1-10 1-10 1-11

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No.20897

Jan. 2001

XM-PX70WT/BU/PN

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.

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

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.).

0.15 F AC TYPE

1500 10W

Place this probe on each exposed metal part.

This corresponds to 0.5 mA AC (r.m.s.).

Good earth ground

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.

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.

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XM-PX70WT/BU/PN

Attention when MD pickup is exchanged

1. About the static electricity protection measures

The laser diode in the traverse unit (optical pick up) is easy to be destroyed by clothes and the human body to the electrified static electricity. Please note the explosion by static electricity when repairing.

2. About the earth processing for the electrostatic destruction prevention

In the equipment which uses an optical pick up (laser diode), an optical pick up is destroyed by the static electricity of the work environment. Please do the earth processing and work.

1) Earth of work stand Please pull the conductive material (conductive sheet) or the iron plate to the depository place of the traverse unit (optical pick up), and take the earth to ground.

2) Human body earth Please use the anti-static wrist strap to exhaust the electrified static electricity to the human body.

anti-static wrist strap

Conductive material (conductive sheet) or the iron plate

3. Handling the optical pick up

1) Please return according to a correct procedure based on short processing after exchanging parts.

2) Do not use a tester to check the condition of the laser diode in the optical pick up .The tester 's internal power source can easily destroy the laser diode.

4. Attention when unit is disassembled

Please refer to "Disassembling method" for how to detach .

1) Please be sure to solder before a flexible wire is removed from connector on a main printed circuit board as shown. if you removes without soldering.the MD picking up assembly might destroy

2) When installing , solder in the part of short round should be removed after a flexible wire is connected with connector.

Solder short

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XM-PX70WT/BU/PN

Disassembly method

Removing the MD door assembly

(See Fig.1 and 2)

Shift the door lever to open the door.

Remove the four screws A and detach the MD

assembly from the main body.

Removing the holder assembly

(See Fig.3 and 4)

Prior to performing the following procedure, remove the MD door assembly.

Turn the holder assembly as shown in Fig.3.

Pull the side arm (L) marked a and

Open the holder assembly as

Move the marked b in the direction of the arrow and release it from the shaft.

shown in Fig.4.

remove outward.

door

MD door assembly

Door lever

Holder assembly

Door lever

Fig.1

MD door assembly

Fig.2

Move the part c inward and pull out the holder assembly from the shaft.

ATTENTION:

“U-shaped” notch

When reassembling, first reattach the part c to the shaft of the chassis assembly. And next, fit the “U-shaped” notch to the shaft.

Holder assembly

Part b

Part a

Side arm (L)

Fig.3

Holder assembly

Part c shaft

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Part c

Fig.4

XM-PX70WT/BU/PN

Removing the chassis assembly

(See Fig.5 to 7)

Prior to performing the following procedure, remove the MD door assembly and the holder assembly.

Open the battery lid. Release the tab d and pull out the battery lid.

Remove the screw B and pull out the side arm (R) upward.

Remove the two screws C and pull out the eject unit.

Remove the screw D, E, F, G and H attaching the chassis assembly respectively.

Disengage the three joints e of the bottom case and the battery holder. Remove the chassis assembly and the jack cover at once.

Tab d

Battery lid

Chassis assembly

Side arm (R)

Joint e

Fig.5

Eject unit

Chassis assembly

Joint e

Bottom case

Battery holder

Fig.6

Chassis assembly

Fig.7

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XM-PX70WT/BU/PN

Removing the main board and the battery holder (See Fig.8 and 9)

Prior to performing the following procedures, remove the MD door assembly, the holder assembly and the chassis assembly.

ATTENTION:

Solder the short circuit round of the flexible wire on the main board.

Disconnect the flexible wires from connector CN301 and CN401 on the main board.

Remove the one screw I attaching the main board. Remove the main board with the battery holder .

Unsolder the four soldered parts f retaining the main board and the battery holder.

Before disconnecting the flexible wire extending from the pickup, make sure to solder the short circuit round to prevent damage to the pickup.

CN401

CN301

Short circuit round

Headphone jack assembly

Short circuit round

Battery holder

Soldering f

Main board

Fig.8

CN401

ATTENTION:

When reassembling, connect the flexible wire extending from the pickup to the connector on the main board and unsolder the short circuit round.

Removing the headphone jack assembly

(See Fig.10)

Prior to performing the following procedures, remove the MD door assembly, the holder assembly, chassis assembly and the main board.

Disconnect the flexible wire extending from the headphone jack from connector CN601 on the main board.

CN301

Fig.9

Battery holder

CN601

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Headphone jack assembly

Main board

Fig.10

XM-PX70WT/BU/PN

<Removal of the MD

mechanism section>

Prior to performing the following procedures, remove the MD door assembly, the holder assembly, the chassis assembly and the main board.

Removing the spindle motor

(See Fig.11)

Unsolder the part g on the flexible wire extending from the underside of the chassis assembly to the spindle motor.

ATTENTION:

Remove the three screws J attaching the spindle motor.

Removing the pickup unit (See Fig.11)

Do not spill flux on the gear and others.

Lead screw

Part i

Pickup unit

Part h

Spindle motor

Lead screw

Chassis assembly

Worm gear

Slit washer

Shaft holder

Part g

Fig.11

ATTENTION:

Remove the slit washer and the worm gear from the underside of the chassis assembly.

Remove the screw K attaching the shaft holder and draw out the shaft (lead screw).

Pull out the pickup unit and the lead screw while disengaging the part h and i.

When handling the pickup unit, touch the parts marked in Fig.13 only.

Removing the pickup (See Fig.12 and 13)

ATTENTION:

When handling the pickup unit, touch the parts marked in Fig.13 only.

Lead spring

Pickup

Fig.12

Touch these parts only.

Remove the screw L and the lead spring.

Pull out the shaft from the pickup.

Fig.13

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XM-PX70WT/BU/PN

Removing the feed motor (See Fig.14)

Peel off the adhesive tape j on the flexible wire on the underside of the feed motor.

Unsolder soldering k connecting the flexible wire to the feed motor.

Remove the two screws M attaching the feed motor.

ATTENTION:

When reassembling, reattach the flexible wire with an adhesive tape and solder.

Feed motor

Chassis assembly

Soldering k

Pickup unit

Fig.14

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