JVC MX KA3UM Service Manual

SERVICE MANUAL

COMPACT COMPONENT SYSTEM

MX-KA3

CA-MXKA3SP-MXKA3 SP-MXKA3

Contents

Safety precautions ---------------------------- 1- 2 Preventing static electricity ----------------- 1- 3 Important for laser products ---------------- 1- 4 Disassembly method ------------------------ 1- 5 Adjustment method -------------------------- 1- 18

Area Suffix

A ........................... Australia

UJ ..................... U.S.Military

UW ................ Latin America

U ................................. Asia

Flow of functional operation until TOC read -------------- 1- 20 Maintenance of laser pickup -------------- 1- 21 Replacement of laser pickup -------------- 1- 21 Description of major ICs ------------------- 1- 22

Wiring connection --------------------------- 1- 33

No.22081

Aug. 2003

MX-KA3

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 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 ( 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.

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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.)

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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 ACtype 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 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.).

) on the Parts List in the Service Manual. The use of a substitute replacement

AC VOLTMETER (Having 1000 ohms/v or more sensitivity)

0.15 F AC TYPE

1500 10W

olts,

Place this probe on each exposed metal part.

Good earth ground

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.

1-2

Preventing static electricity

1. Grounding to prevent damage by 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.

2. About the earth processing for the destruction prevention by static electricity

In the equipment which uses optical pick-up (laser diode), optical pick-up is destroyed by the static electricity of the work environment. Be careful to use proper grounding in the area where repairs are being performed.

2-1 Ground the workbench

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.

2-2 Ground yourself

Use an anti-static wrist strap to release any static electricity built up in your body.

(caption) Anti-static wrist strap

MX-KA3

Conductive material (conductive sheet) or iron plate

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 testers internal power source can easily destroy the laser diode.

4. Handling the CD changer unit (optical pickup)

1. Do not subject the CD changer 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 CD changer 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.

CD changer

unit

Attention when traverse unit is decomposed

Please refer to “Disassembly method ” in the text for

pick up and how to detach the CD changer mechanism.

1. Remove the CD changer unit.

2. Disconnect the harness from connector on the CD motor board.

3. Solder is put up before the card wire is removed from connector Cn601on the main board as shown in Fig.1 and Fig. 2. (When the wire is removed without putting up solder, the CD pick-up assembly might destroy.)

4. Please remove solder after connecting the card wire with CN601 when you install picking up in the substrate.

Flexible cable

Fig.1

Soldering

Fig.2

1-3

MX-KA3

Important for laser products

1. CLASS 1 LASER PRODUCT

2. DANGER :

inter lock failed or defeated. Avoid direct exposure to beam.

3. CAUTION :

Laser Unit. Do not disassemble the Laser Unit. Replace the complete Laser Unit if it malfunctions.

4. CAUTION :

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 defeated. It is dangerous to defeat the safety switches.

Invisible laser radiation when open and

There are no serviceable parts inside the

The compact disc player uses invisible

5. CAUTION :

able to function.

6. CAUTION :

of procedures other than those specified herein may result in hazardous radiation exposure.

CAUTION Please use enough caution not

If safety switches malfunction, the laser is

Use of controls, adjustments or performance

to see the beam directly or touch it in case of an adjustment or operation check.

FUSE CAUTION

CAUTION:

REPLACE WITH SAME TYPE AND RATING FUSE (S).

ATTENTION:

REMPLACER PAR UN(LES) FUSIBLE(S) DE MEME TYPE ET DE MEME VALEUR

1-4

Disassembly method

Commence disassembly of the set by removing the main units and then proceed to the components and assemblies inside the units.

Replacement of the fuses and the power IC

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Top cover

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CD changer unit

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Front panel assembly

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Chassis unit

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CD changer unit

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Removing the main PCB

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Removing the CD changer mechanism assembly

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Removing the CD pickup

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Replacing the loading motor and belt of the CD changer tray

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Replacing the CD tray rotor belt of CD changer, and removing the motor

MX-KA3

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Front panel assembly

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Removing the cassette deck mechanism

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Removing the earphone jack PCB

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Removing the control/FL PCB

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Removing the switch PCB and ACTIVE BASS EX. switch PCB

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Removing the cassette deck main motor, and replacing the main belts

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Removing the leaf switches of the cassette deck mechanism

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Removing the cassette deck heads

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Chassis unit

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Removing the 3-pin regulator

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Removing the power amp and supply PCB and the Power Trans PCB

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Removing the sub power PCB

1-5

MX-KA3

Replacement of the fuses and the power IC

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Replacing the fuses (See Fig.1)

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Prior to performing the following procedure, remove

the left side BOARD.

1. Replace the fuses inside.

[Caution] Be sure to use fuses with the specified

ratings.

Fuse(F951) T2AL 250V

Fuse(F952) T1.6AL 250V

Fuse(F953) T1AL 250V

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Replacing the heat sink cover (See Fig.3)

1. Remove four screws B from the rear panel.

2. Pull the heat sink cover outward.

Fig.1

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Replacing the power IC (See Fig.2)

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Prior to performing the following procedure, remove

the top cover.

1. Remove the two screws A from the heat sink between the power IC.

2. Remove the solder fixing the power IC.

CA-MXKA3A Fig.3 (A)

CA-MXKA3U/UJ/UW Fig.3 (B)

1-6

Fig.2

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Removing the top cover

(See Fig.4 and 5)

1. Remove six screws C that retain the top cover from the panel rear of the body.

2. Remove six screws D that retain the top cover from the two sides of the body.

3. Remove the top cover from the body by lifting it toward the rear.

MX-KA3

Top cove

CA-MXKA3A Fig.4 (A)

Right Front panel assembly

Top cove

CA-MXKA3U/UJ/UW Fig.4 (B)

Left Front panel assembly

Fig.5

1-7

MX-KA3

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Removing the CD changer unit

(See Fig.6 to 9)

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Prior to performing the following procedures, remove

the top cover.

[Caution] Although the CD mechanism unit can be

removed without removing the CD tray panel, it is still recommended to remove it in order to prevent damage.

a. From the front panel side of this set, push in the

sections marked with arrows and pull out the CD tray toward the front.

b. Remove the CD tray panel by pushing both of its

extremities upward in the direction of the arrows.

c. Push the CD tray deep into the set.

1. Disconnect the cord wires from the CD PCB CN703 and CN203.

2. From the rear of the set, remove two screws E

three screws F and four screws G on the front panel left and right side.

3. Handle the CD changer unit rear, take out the unit.

CD tray panel

CA-MXKA3A Fig.8 (A)

Antenna termianl

Aux terminal

Antenna termianl

Aux terminal

CD tray panel

CA-MXKA3U/UJ/UW Fig.8 (B)

Fig.6

CD changer unit

Fig.9

Fig.7

1-8

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Removing the front panel assembly

(See Fig.10 to 11)

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Prior to performing the following procedures, remove

the top cover.

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Also remove the CD changer unit.

1. Disconnect the parallel wire and the cord wire from the connectors CN701, CN101 on the power amp. PCB.

2. Remove one screws H retaining the front panel assembly onto the bottom of the body.

3. Remove two screws I on the left and right side of the set retaining the panel front from the bottom and then remove then GND lug b that comes from the power amp and supply PCB.

4. Disengage the claws c on both sides of the front panel assembly and then remove the assembly.

MX-KA3

Fig.10

er amp andPow

supply PCB

GND lug b

Fig.11

Claw c

1-9

MX-KA3

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Removing the CD PCB

(See Fig.12 to 13)

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Prior to performing the following procedures, remove

the top cover.

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Also remove the CD changer unit.

1. Disconnect the wires from CN603A, CN603B and CN604 on the CD PCB, which is located on the back side of the CD changer unit.

2. The 4 screws J that retain the CD PCB should be removed.

3. Remove the CD PCB by pulling it toward the side where the CN601 is located.

4. Using solder, short the CD pickup to connect to short round.

[Caution] After re-connecting the wires, be sure to

remove the shorting solder from the GND connection.

5. Disconnect the card wire from the connector CN601 on the main PCB and then remove the main PCB.

CD PCB

Fig.12

CN601

Short round

Fig.13

1-10

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Removing the CD changer mechanism

assembly (See Fig.14 to 15)

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Prior to performing the following procedures, remove

the top cover.

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Also remove the CD changer unit.

1. Turn the CD changer mechanism cover base and remove the screws d connecting the unit to the CD changer mechanism assembly.

2. Removing four screws e retaining the CD mechanism holder assembly.

[Caution] When replacing the CD changer mechanism

assembly, be sure not to mistake the positions of the silver color and copper color spring.

MX-KA3

CD changer unit

CD changer mechanism assemb

e ( Silver color)

Fig.14

e ( copper color)

Fig.15

1-11

+ 23 hidden pages