JVC TH-A5 Schematic

SERVICE MANUAL

DVD DIGITAL THEATER SYSTEM

TH-A5

Area suffix

J ------------------- U.S.A. C ---------------- Canada

TH-A5

ANDBY/ON

AUDIO

VCR

CONTR

VCR

OFF

TV CHANNEL

TOP MENU

AUDIO/

SUBTITLE

TV VOLUME

FM MODE

STEP

TV/VIDEO

DISPLAY

RETURN

TUNER PRESET

DOWN UP

REW

VCR CHANNEL

TUNING

B.SEARCH F.SEARCH

ENTER

VOLUME

DVD FM/AM AUX MUTING

RM-STHA5J

DVD THEATER SYSTEM

STANDB

STANDBY/ON

COMPACT

DIGITAL VIDEO

AUDIO/FM MOD

Contents

Safety precautions Importance administering point on the safety Preventing static electricity

SP-XCA5SP-XSA5 2

OLUME

SOURCE

DVD DIGITAL THEATER SYSTEM TH-A

SP-XSA5 2

DIGITAL

SURROUND

DIGITAL

XV-THA5 SP-WA5

1-2

1-3 1-4

Disassembly method Wiring connection Adjustment method Description of major ICs

1-5 1-12 1-13 1-15~33

No.21060

Jan. 2002

TH-A5

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.)

1-2

Importance administering point on the safety

160mA 250V

4A 125V

TH-A5

Main board (Forward side)

Caution: For continued protection against risk of fire, replace only with same type 4A/125V for FU1, 160mA/250V for FU3 . This symbol specifies type of fast operating fuse.

Precaution: Pour eviter risques de feux, remplacez le fusible de surete de et FU1 comme le meme type que 5A/125V, et 160mA/250V pour FU3. Ce sont des fusibles suretes qui functionnes rapide.

1-3

TH-A5

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

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.

4.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.

Attention when traverse unit is decomposed

*Please refer to "Disassembly method" in the text for pick-up and how to detach the substrate.

Solder is put up before the card

1. wire is removed from connector on the pick up board as shown in Figure. (When the wire is removed without putting up solder, the CD pick-up assembly might destroy.) Please remove solder after

2. connecting the card wire with when you install picking up in the substrate.

DVD mechanism assembly (bottom side)

DVD loading mechanism

Pick up board

Card wire

Short land

(These two points are soldered respectively, and are made to short-circuit)

Connector

1-4

DVD loader board

TH-A5

Disassembly method

Removing the top cover (See Fig.1)

Remove the four screws A attaching the top cover on the both sides of the body.

Remove the two screws B on the back of the body.

Remove the top cover from behind in the direction of the arrow while pulling both sides outward.

Removing the front panel assembly

(See Fig.2A, 2B and 3)

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

Remove the one screw a and remove the earth wirer.

2. Remove the three screws C attaching the front panel assembly on the bottom of the body.

3. Remove the two screws D attaching the front panel assembly on the both sides of the body.

4. Remove the claw1, claw2 and claw3, and detach the front panel assembly toward the front.

5. Disconnect the card wire from the connector DW20

Top cover

Claw1

(bottom side)

Claw2 (both side)

Fig.1

Front panel assembly

Fig.2A

Front panel

assembly

Claw3

Removing the power cord (See Fig.4)

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

Disconnect the power cord from the connector CW1 on the main board and pull up the cord stopper upward.

Notes : The power cord is exchangeable.

Power cord

CW1

Tie band

(both side)

(fixing the earth wire)

Fig.2B

DSP board

DW20

Rear panel

Fig.4

Power cord

stopper

Front panel assembly

(Inner side)

Display board

Fig.3

1-5

TH-A5

Removing the DVD mechanism assembly (See Fig.5 and 6)

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

Disconnect the card wire from the connector J14 and J21 on the DVD MPEG board.

Remove the two screws E attaching the DVD mechanism assembly and pull up with drawing out.

Disconnect the harness from the connector J2 on the DVD loader board.

Removing the rear panel (See Fig.7 and 8)

Prior to performing the following procedure, remove the top cover and power cord.

Disconnect the harness from the connector NW11 on the DSP board.

Remove the two screws F, four screws G, one screw I and five screws J attaching the each boards to the rear panel.

Rear panel

DVD mechanism assembly

DVD MPEG board

J14

J21

Fig.5

DVD mechanism assembly

Remove the three screws K attaching the rear panel on the back of the body.

Removing the tuner pack (See Fig.7 and 8)

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

Disconnect the card wire from the connector CON01 on the tuner pack.

Remove the two screws F attaching the tuner pack to the rear panel.

Removing the jack board (See Fig.7 and 8)

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

Disconnect the card wire from the connector VW2 on the jack board.

Remove the four screws G attaching the jack board to the rear panel.

Disconnect the connector VW1 on the jack board and pull up the jack board.

Fan motor

DVD loader board

Fig.6

Rear panel

KKK

Fig.7

DSP board

Removing the fan motor (See Fig.7 and 8)

Prior to performing the following procedures, remove the top cover .

Disconnect the harness from the connector NW11 on the DSP board .

Removing the two screws H attaching the fan motor on the rear panel.

1-6

Rear panel

NW11

(on the

DSP board)

Jack

board

Fig.8

VW1

CON01

VW2

Tuner pack

TH-A5

Removing the DSP board (See Fig.9)

Prior to performing the following procedure, remove the top cover, the front panel assembly and jack board.

Untied the harness band and disconnect the harness from the connector CW2 on the main board.

Disconnect the harness from the connector NW11 on the DSP board.

Disconnect the card wire from the connector VW12 on the DSP board.

Remove the one screw I attaching the DSP board to the rear panel (see fig.7).

Pull up the DSP board from the front side upwards disconnecting the connector DW10, DW13, DW14 and DW15.

Removing the main board (See Fig.10)

Prior to performing the following procedure, remove the top cover, front panel assembly, DVD mechanism assembly, jack board and DSP board.

Disconnect the card wire from the connector CW4 and CW8 on the main board.

board

(Front panel side)

Main board

CW8

VW12

Harness band

DW14DW15

Fig.9

Main board

CW2

NW11

(Rear panel side)

DW10DW13

Heat sink

(to which

power

transistor

is attached)

Disconnect the harness from the connector CW3 on the main board.

Remove the five screws J attaching the speaker terminals and jack to the rear panel (see fig.7).

Remove the six screws L1 (short) and one screw L2 (long) attaching the main board.

When the rear panel is not removed, pull up the main board from front side.

Removing the power transistor & power IC (See Fig.10 and 11)

Prior to performing the following procedure, remove the top cover, front panel assembly, DVD mechanism assembly, jack board, DSP board and main board.

After removing the solder part soldered to the main board, remove each screw and remove the heat sink from Power transistor.

After removing the solder part soldered to the main board, remove each screw and remove the heat sink from Power IC.

CW4

Fig.10

(Each power transistor is fixed)

Solder part

Solder part Solder part

Heat sink (to which power IC is attached)

Fig.11

CW3 Power ICs

Main board

(Reverse side )

Solder part (Power IC is fixed)

1-7

TH-A5

Removing the DVD power board (See Fig.12)

Prior to performing the following procedure, remove the top cover, front panel assembly and DSP board.

Disconnect the harness and card wire from the connector PW1, PW2 and PW5 on the DVD power board.

Remove the one screw M1 (short) and two screws M2 (long) attaching the DVD power board.

PW5 PW2

DVD

power

board

Removing the power transformer (See Fig.12)

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

Cut off the tie band fixing the harness, if needed.

Disconnect the harness from the connector CW2 on the main board (see fig.9) and PW1, PW2 on the DVD power board.

Remove the four screws N attaching the power transformer.

PW1

Tie band

Power transformer

Fig.12

Removing the display board & switch board (See Fig.1 and 2)

Prior to performing the following procedure, remove the top cover and the front panel assembly.

Disconnect the card wire from the connector FW1 on the display board.

Remove the five screws A attaching the display board on the inner of the front panel assembly.

Remove the four screws B attaching the switch board on the inner of the front panel assembly.

Disconnect the harness from connector FW2 on the display board, if needed.

Removing the front window (See Fig.2 and 3)

Prior to performing the following procedure, remove the top cover, front panel assembly, display board and switch board.

FW1

Display board

Switch button

Front panel assembly

Switch board

FW2

Fig.1

(inner side)

CCC

Claw

Fig.2

Front panel assembly (front side)

Remove the switch buttons, if needed.

Remove the three screws C attaching the front

2. window on the front panel.

Remove the eight claws fixing the front window on

3. the front panel.

1-8

Front window

Fig.3

TH-A5

Removing the DVD loader board (See Fig.1 to 3)

Prior to performing the following procedure, remove the top cover and DVD mechanism assembly.

Disconnect the card wire from the connector J6 on the DVD MPEG board.

Disconnect the harness from the connector on the motor board.

Disconnect the harness from the connector J5 on the DVD loader board.

Remove the four screws A attaching the DVD loader board to DVD mechanism assembly.

CAUTION!! (see fig.3)

Before removing the card wire which connects the pickup board and DVD loader board, solder the two soldering parts and make it short-circuit. Moreover, while having removed the card wire, don't remove these solder.

DVD MPEG board

DVD loader board

DVD mechanism assembly

(top side)

Fig.1

DVD mechanism assembly

(bottom side)

Motor board

Connector

Fig.2

Disconnect the card wire from the connector U9 on the DVD loader board.

ONE POINT

How to eject the DVD tray manually (see fig.2)

The white lever of the mark is moved in the direction of the arrow. Then, the tray will be opened. Moreover, the tray is separable from a DVD mechanism assembly by removing two screws of the mark (see fig.1) and drawing out the tray.

Removing the DVD loading mechanism (See Fig.4)

Prior to performing the following procedure, remove the top cover, DVD mechanism assembly and DVD loader board.

Remove the two screws B and remove the bracket.

Remove the one screw C fixing the DVD loading mechanism.

Pick up

board

Lever

Soldering parts

Motor board

Fig.3

DVD mechanism assembly

Bracket

DVD loading

mechanism

(bottom side)

DVD loading

mechanism

Move the lever in the direction of the arrow X.

Remove the DVD loading mechanism from the DVD mechanism assembly by moving it in the direction of the arrow Y.

Fig.4

1-9

TH-A5

)

Removing the DVD traverse mechanism

(See Fig.5)

Prior to performing the following procedure, remove the top cover, DVD mechanism assembly, DVD loader board and DVD loading mechanism.

Remove the four screws D attaching the DVD traverse mechanism to DVD loading mechanism.

Removing the holder & DVD MPEG board (See Fig.6 and 7)

Prior to performing the following procedure, remove the top cover, DVD mechanism assembly and DVD loader board.

Remove the two claws1, and remove the holder from the DVD mechanism assembly as it is pushed down.

DVD traverse

mechanism

Claw1

Holder

DVD loading mechanis

(top side

Fig.5

Note: When removing only the DVD MPEG board, it is not necessary to remove this holder.

Remove the four claws2 and remove the DVD MPEG board from the holder.

ONE POINT

When inserting DVD MPEG board in holder. (see fig.8)

Holder

DVD mechanism assembly

Fig.6

DVD MPEG board

Fig.7

DVD MPEG board

(bottom side)

Claw2

1-10

Insert in after uniting with a lower claws, when inserting DVD MPEG board in holder.

Fig.8

TH-A5

<Speaker section> [SP-XSA5 / Satellite speaker]

It is exchange in a unit.

[SP-XCA5 / Center speaker]

It is exchange in a unit.

[SP-WA5 / Woofer]

Removing the speaker unit (See Fig.1 to 3)

Remove the four bosses and remove the net assembly.

Notes: It will be good to use the tool with a flat tip, since it is hard to remove. Please take care not to damage the cabinet at this time.

Remove the eight screws A attaching the speaker unit to cabinet.

Disconnect the code from the two terminals of the speaker unit.

Net assembly

Boss

Fig.1

Speaker unit

Cabinet

Fig.2

Terminals

red

Speaker unit (reverse side)

Fig.3

Code

black

1-11

+ 23 hidden pages

JVC TH-A5 Schematic

Specifications and Main Features

Frequently Asked Questions

User Manual

Importance administering point on the safety

Preventing static electricity

Disassembly method