JVC XMPX70WT - Service Manual Immediate Download

SERVICE MANUAL

PORTABLE MINIDISC PLAYER

No.20897

Jan. 2001

2001 VICTOR COMPANY OF JAPAN, LTD.

XM-PX70WT/BU/PN

Area Suffix

Hong Kong

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

1-2

1-3

1-4

1-9

1-10

1-11

1-24

XM-PX70WT/BU/PN

1-2

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.).

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

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.

XM-PX70WT/BU/PN

1-3

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.

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.

2. About the earth processing for the electrostatic destruction prevention

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.

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 .

Conductive material (conductive

sheet) or the iron plate

anti-static wrist strap

Attention when MD pickup is exchanged

1. About the static electricity protection measures

Solder short

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.

XM-PX70WT/BU/PN

1-4

Shift the door lever to open the door.

Remove the four screws A and detach the MD door

assembly from the main body.

Disassembly method

Removing the MD door assembly

(See Fig.1 and 2)

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 remove outward.

Open the holder assembly as

shown in Fig.4.

Move the marked b in the direction of the arrow and

release it from the shaft.

Move the part c inward and pull out the holder

assembly from the shaft.

Removing the holder assembly

(See Fig.3 and 4)

When reassembling, first reattach the

part c to the shaft of the chassis

assembly. And next, fit the "U-shaped"

notch to the shaft.

ATTENTION:

MD door assembly

Door lever

Fig.1

Fig.2

Fig.3

Fig.4

Holder assembly

Part a

Part b

"U-shaped" notch

Part c shaft

Side arm (L)

Holder assembly

Part c

XM-PX70WT/BU/PN

1-5

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.

Removing the chassis assembly

(See Fig.5 to 7)

Fig.5

Fig.6

Fig.7

Chassis assembly

Side arm (R)

Battery lid

Tab d

Joint e

Battery lid

Chassis assembly

Eject unit

Chassis assembly

Joint e

Bottom case

Battery holder