JVC RD-T70BU Service Manual

SERVICE MANUAL

CD PORTABLE SYSTEM

RD-T70BU

Area suffix

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

Contents

Safety precautions Preventing static electricity Important for laser products Disassembly method Adjustment method Flow of functional operation until TOC read

1-2 1-3 1-4 1-5 1-12

1-14

Maintenance of laser pickup Replacement of laser pickup Description of major ICs Wiring connection

1-15 1-15 1-16 1-25

No.21164

Dec. 2002

RD-T70BU

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 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.).

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. 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.

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. (This regulation does not correspond to J and C version.)

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RD-T70BU

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

Static electricity in the work area can destroy the optical pickup (laser diode) in devices such as CD players. 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

Conductive material (conductive sheet) or iron plate

3. Handling the optical pickup

In order to maintain quality during transport and before installation, both sides of the laser diode on the

1. replacement 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

2. source can easily destroy the laser diode.

4. Handling the traverse unit (optical pickup)

Do not subject the traverse unit (optical pickup) to strong shocks, as it is a sensitive, complex unit.

Remove solder of the short land on the flexible wire 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.

Handle the flexible wire carefully as it may break when subjected to strong force.

It is not possible to adjust the semi-fixed resistor that adjusts the laser power. Do not turn it.

5. Attention when traverse unit is decomposed

*Please refer to "Disassembly method" in the text for the CD pickup unit.

Apply solder to the short land before the flexible wire is disconnected from the connector on the CD pickup unit. (If the flexible wire is disconnected without applying solder, the CD pickup may be destroyed by static electricity.) In the assembly, be sure to remove solder from the short land after connecting the flexible wire.

CD pickup unit

Short land

Flexible wire

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RD-T70BU

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 laserradiation and is equipped with safety switches whichprevent 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.

VARNING : Osynlig laserstrålning är denna del är öppnad

och spårren är urkopplad. Betrakta ej strålen.

VARO : Avattaessa ja suojalukitus ohitettaessa olet

alttiina näkymättömälle lasersäteilylle.Älä katso säteeseen.

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.

CAUTION

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

ADVARSEL : Usynlig laserstråling ved åbning , når

sikkerhedsafbrydere er ude af funktion. Undgå udsættelse for stråling.

ADVARSEL : Usynlig laserstråling ved åpning,når

sikkerhetsbryteren er avslott. unngå utsettelse for stråling.

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Disassembly method

Removing the front cabinet assembly and rear cabinet assembly (See Figs.1 to 4)

Remove the two screws A and two screws B retaining the front cabinet and rear cabinet assemblies from the rear of the body.

Remove the battery door from the rear of the body, then remove the screw C retaining the front cabinet and rear cabinet assemblies.

Remove the two screws D retaining the CD door lens from the top of the body with a hexagonal wrench.

[Caution] If the CD door cannot be opened, the

screws E which are to be removed in step 4 will not be removable. In this case, it is necessary to remove the CD door lens.

Fig.1

RD-T70BU

Battery door

LCD lens

4.5.Remove the two screws E retaining the front cabinet assembly from the top of the body.

Disconnect the speaker wire from the connector CN301 on the main board, then remove the front cabinet assembly from the rear cabinet assembly.

(See Fig.4.)

Front cabinet assembly

CD door lens

Fig.2

Rear cabinet assembly

Fig.3

Front cabinet assembly

Speaker wire

Fig.4

CN301

Rear cabinet assembly

Main board

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RD-T70BU

Prior to performing the following procedures, remove the front cabinet assembly from the rear cabinet assembly.

Remove the right and left speaker assemblies (See Figs.5 and 6)

1.2.Remove the six screws F retaining the speaker net from the inside of the front cabinet assembly.

Remove the tie band fixing the speaker wires.

[Note] When installing the speaker assemblies,

pass each speaker wire through the notches a to d at the bottom of the front cabinet before bundling the wire.

3.Remove the eight screws G retaining the right and left speaker assemblies from the outside of the front cabinet assembly.

Prior to performing the following procedures, remove the front cabinet assembly from the rear cabinet assembly.

Front cabinet assembly Speaker net

Tie band

Notch a

Notch b

Notch c

Speaker wire

Notch d

Fig.5

Left speaker

Front cabinet assembly

Right speaker

Removing the top cabinet assembly

(See Figs.7 to 9)

Remove the screw H retaining the top cabinet assembly from the rear of the rear cabinet assembly.

Disconnect the wires from the connectors CN302 and CN303 on the main board at the front of the rear cabinet assembly. (See Fig.8.)

Loosen the screw J clamping the FM antenna wire.

Pull the top cabinet assembly slightly towards front and separate it from the rear cabinet assembly, then remove the FM antenna wire from the post pin on the main board and remove the top cabinet assembly.

[Caution] When installing the top cabinet

assembly, be sure to connect the FM antenna wire.

FM antenna wire

CN303

CN302

Fig.6

Top cabinet assembly

Rear cabinet assembly

Fig.7

Top cabinet assembly

Rear cabinet assembly

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Main board

Fig.8

Post pin

FM antenna wire

Rear cabinet assembly

WireWire

Fig.9

Main board

RD-T70BU

Removing the power supply board and transformer assembly

Prior to performing the following procedures, remove the top cabinet assembly from the rear cabinet assembly.

Remove the three screws K retaining the power supply board.

Remove the two screws L retaining the transformer assembly.

Pull out the power supply board from notches e and f and remove it together with the transformer assembly.

[Note] After assembly, apply a locking agent to

the screw L.

(See Fig.10)

Removing the battery board (See Figs.11 and 12)

Disconnect the wire from the connector CN302 on the main board. (See Fig.11.)

Remove the solder g fixing the wire.

Lift the claw j on the bottom of the rear cabinet assembly slightly and remove the battery board by pulling it in the direction of the arrow.

Notch e

Rear cabinet assembly

Main board

Solder g

Notch h

Fig.10

Fig.11

Power supply board

Transforme assembly

Wire

Notch i

Notch f

CN302

Wire

[Note] When installing the battery board, pass

the wires through the notches h and i at the bottom of the rear cabinet.

Removing the handle (See Fig.13)

Prior to performing the following procedures, remove the top cabinet assembly from the rear cabinet assembly.

Open hooks k and m on the left and right sides of the rear cabinet assembly and remove the handle by pulling it toward the rear.

Rear cabinet assembly

Hook k

Claw j

Battery board

Fig.12

Handle

Hook m

Fig.13

Rear cabinet

assembly

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RD-T70BU

[Caution] When removing the board assembly,

be careful not to scratch or damage the top cabinet or the CD door.

Removing the main board

(See Figs.14 to 16)

Remove the three screws M retaining the main board.

Disconnect the wire and card wires from the connectors CN708, CN801 and CN802 on the main board. (See Fig.14.)

Disconnect the wire from the connector CN804 on the key 2 board. (See Fig.14.)

Disconnect the wire from the connector CN714 on the door switch board. (See Fig.14.)

Disconnect the wire from the connector P011 on the CD mechanism board. (See Fig.14.)

Lift the main board slightly in the direction of the arrow and apply solder to short land section n on the CD pickup unit. (See Figs.15 and 16.)

[Caution] Be sure to apply solder in order to

short land section n on the CD pickup unit before removing the wire from the CD pickup unit (see Fig. 16). If the card wire is removed without applying this solder, the CD pickup may be damaged.

7.After soldering, disconnect the card wire from the connector CN701 on the main board. (See Fig.15.)

CD mechanism board

Door switch board

CN708

CN802

CN714

Wire

Short land section n

Main board

P011

Card wires

Fig.14

CN701

Fig.15

Key 2 board

CN804

Wire

CN801

Main board

CD pickup unit

Top cabinet

[Caution] After re-connecting the card wire,

be sure to remove the solder from short land n.

1-8

CD pickup unit

Short land section n

Fig.16

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