Jvc KD-G279-UR Service Manual

SERVICE MANUAL

CD RECEIVER

MA26620064

KD-G279UR

Lead free solder used in the board (material : Sn-Ag-Cu, melting point : 219 Centigrade)

TABLE OF CONTENTS

1 PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

No.MA266

2006/4

SPECIFICATION

AUDIO AMPLIFIER SECTION

Power Output 17 W RMS × 4 Channels at 4 Ω and [< or =] 1% THD+N Signal to Noise Ratio 80 dBA (reference: 1 W into 4 Ω) Load Impedance 4 Ω (4 Ω to 8 Ω allowance)

Tone Control Range Bass ±10 dB at 100 Hz

Treble ±10 dB at 10 kHz

Frequency Response 40 Hz to 20 000 Hz

Line-Out Level/Impedance 2.5 V/20 kΩ load (full scale) Output Impedance 1 kΩ

TUNER SECTION

Frequency Range FM 87.5 MHz to 107.9 MHz (with channel interval set to 100 kHz or

200 kHz)

87.5 MHz to 108.0 MHz (with channel interval set to 50 kHz)

AM 530 kHz to 1 710 kHz (with channel interval set to 10 kHz)

531 kHz to 1 602 kHz (with channel interval set to 9 kHz)

FM Tuner Usable Sensitivity 11.3 dBf (1.0 µV/75 Ω)

50 dB Quieting Sensitivity 16.3 dBf (1.8 µV/75 Ω)

Alternate Channel Selectivity (400 kHz) 65 dB

Frequency Response 40 Hz to 15 000 Hz

Stereo Separation 35 dB

Capture Ratio 1.5 dB

AM Tuner Sensitivity 20 µV

Selectivity 35 dB

CD PLAYER SECTION

Type Compact disc player

Signal Detection System Non-contact optical pickup (semiconductor laser)

Number of channels 2 channels (stereo)

Frequency Response 5 Hz to 20 000 Hz

Dynamic Range 96 dB

Signal-to-Noise Ratio 98 dB

Wow and Flutter Less than measurable limit

MP3 Decoding Format MPEG1/2 Audio Layer 3

Max. Bit Rate: 320 kbps

WMA (Windows Media® Audio) Decoding Format Max. Bit Rate: 192 kbps

GENERAL

Power Requirement Operating Voltage DC 14.4 V (11 V to 16 V allowance)

Grounding System Negative ground

Allowable Operating Temperature 0°C to +40°C Dimensions (W × H × D) Installation Size (approx.) 182 mm × 52 mm × 150 mm

Panel Size (approx.) 188 mm × 58 mm × 11 mm

Mass (approx.) 1.2 kg (excluding accessories)

Design and specifications are subject to change without notice.

1-2 (No.MA266)

1.1 Safety Precautions

SECTION 1

PRECAUTIONS

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.

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

(No.MA266)1-3

1.2 Preventing 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.

1.2.1 Grounding to prevent damage 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.

(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) 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 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 source can easily destroy the laser diode.

1.3 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.

1.4 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.

Pickup

Wires

Push switch

1-4 (No.MA266)

Base board

Frame

Flexible wire

Connector

CD mechanism assembly

Pickup

1.5 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 CD,MD and DVD player uses invisible

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.

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 here in may result in

hazardous radiation exposure.

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

REPRODUCTION AND POSITION OF LABELS

WARNING LABEL

CAUTION : Visible and Invisible

CLASS 1 LASER PRODUCT

laser radiation when open and interlock failed or defeated. AVOID DIRECT EXPOSURE TO BEAM. (e)

ADVARSEL : Synlig og usynlig laserstråling når maskinen er åben eller interlocken fejeler. Undgå direkte eksponering til stråling. (d)

VARNING : Synlig och osynling laserstrålning när den öppnas och spärren är urkopplad. Betrakta ej strålen. (s)

VARO : Avattaessa ja suojalukitus ohitettuna tai viallisena olet alttiina näkyvälle ja näkymättömälle lasersäteilylle. Vältä säteen kohdistumista suoraan itseesi. (f)

(No.MA266)1-5

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.

1-6 (No.MA266)

SECTION 3

DISASSEMBLY

3.1 Main body section

3.1.1 Removing the front panel assembly (See Fig.11)

(1) Push the detach button in the lower right part of the front

panel assembly and remove the front panel assembly.

3.1.2 Removing the bottom cover (See Fig.2)

(1) Turn the main body up side down. (2) Insert a screwdriver under the joints to release the two

joints a on the left side, two joints b on the right side and joint c on the back side of the main body, then remove the bottom cover from the main body.

Note:

When releasing the joints using a screwdriver, do not damage the main board.

Joint a

Front panel assembly

Fig.1

Bottom cover

Detach button

Joint

3.1.3 Removing the front chassis assembly (See Fig.3)

• Remove the front panel assembly and bottom cover.

(1) Remove the two screws A on the both sides of the main

body.

(2) Release the joint d and joint e on the both sides of the main

body, then remove the front chassis assembly toward the front.

Joint a

Joint c

Joint d

Front chassis assembly

Joint b

Fig.2

Joint e

Fig.3

(No.MA266)1-7

3.1.4 Removing the side panel (See Fig.4)

Reference:

Remove the front panel assembly as required. (1) Remove the screw B and two screws C attaching the side

panel on the left side of the main body.

(2) Remove the side panel from the main body.

3.1.5 Removing the rear bracket (See Fig.5)

• Remove the bottom cover.

(1) Remove the three screws D, three screws E and two

screws F attaching the rear bracket on the back side of the main body.

(2) Remove the rear bracket.

3.1.6 Removing the main board (See Figs.5 and 6)

• Remove the front panel assembly, bottom cover and side pan-

el.

Reference:

Remove the front chassis assembly as required. (1) Remove the three screws D attaching the rear bracket on

the back side of the main body. (See Fig.5.)

(2) Remove the two screws G attaching the main board. (See

Fig.6.)

(3) Disconnect the connector CN501

the main body and take out the main board with the rear bracket. (See Fig.6.)

Reference:

Remove the rear bracket from the main body as required. (See "3.1.5 Removing the rear bracket".)

on the main board from

Side panel

Fig.4

Rear bracket

Fig.5

CN501

Main board

1-8 (No.MA266)

Rear bracket

Fig.6

3.1.7 Removing the CD mechanism assembly

(See Fig. 7)

• Remove the front panel assembly, bottom cover, side panel,

rear bracket and main board.

Reference:

Remove the front chassis assembly as required.

(1) Remove the three screws H attaching the CD mechanism

assembly on the top chassis.

(2) Take out the CD mechanism assembly.

3.1.8 Removing the switch board

(See Figs.8 to 10)

• Remove the front panel assembly.

(1) Remove the four screws J on the back side of the front pan-

el assembly. (See Fig.8.) (2) Release the joints f and remove the rear cover. (See Fig.9.) (3) Release the joint g and take out the switch board from the

front panel assembly. (See Fig.10.)

CD mechanism assembly

Rear cover

Fig.7

Fig.8

Joints f

Top chassis

3.2 CD mechanism assembly

For CD mechanism, please refer mechanism amnual No. MY005.

Joints f Joints f

Switch board

Joints f

Fig.9

Joint g

Fig.10

Front panel assembly

(No.MA266)1-9

SECTION 4

ADJUSTMENT

4.1 Adjustment method

 Test instruments required for adjustment

(1) Digital oscilloscope (100MHz) (2) Electric voltmeter (3) Digital tester (4) Tracking offset meter (5) Test Disc JVC :CTS-1000 (6) Extension cable for check

EXTSH002-22P × 1

 Standard volume position

Balance and Bass &Treble volume : lndication"0" Loudness : OFF

 How to connect the extension cable for adjusting

Caution:

Be sure to attach the heat sink and rear bracket onto the power amplifier IC and regulator IC respectively, before supply the power. If voltage is applied without attaching these parts, the power amplifier IC and regulator IC will be destroyed by heat.

 Standard measuring conditions

Power supply voltage DC14.4V(10.5 to 16V)

Load impedance 20KΩ(2 Speakers connection)

Output Level Line out 2.0V (Vol. MAX)

 Dummy load

Exclusive dummy load should be used for AM,and FM. For FM dummy load,there is a loss of 6dB between SSG output and antenna input.The loss of 6dB need not be considered since direct reading of figures are applied in this working standard.

1-10 (No.MA266)

Heat sink

Extension cable

EXTSH002-22P

Rear bracket

5.1 Feed section

SECTION 5

TROUBLESHOOTING

5.2 Focus section

Is 4V present at both sides of the feed motor?

Is the voltage output at pin 4 and pin 5 of IC501?

Is the voltage input at pin 28 of IC501?

Is the voltage output at pin 7 of IC521?

NO Is the power supply present at pin 37, pin 49, pin 53, pin 56 and pin 72 of IC521?

Check the connections of CD8V power supply.

YES

Check the feed motor.

Check the connections

YES

between the feed motor and IC501.

Is the power supply

YES YES

present at pin 3, pin 12 and pin 21 of IC501?

Check the connections of CD8V power supply.

Check the connections

YES

between IC501 and IC521.

YES

Check IC521.

Check IC501.

When the lens is moving:

Does the S-search waveform appear at IC501 pins 8 and 9?

Is the voltage input at pin 15 of IC501?

Is the voltage output at pin 13 of IC521?

Is the power supply present at pin 37, pin 49, pin 53, pin 56 and pin 72 of IC521?

YES

Check the pickup and its connections.

Is the power supply

YES

present at pin 3, pin 12 and pin 21 of IC501?

Check the connections of CD8V power supply.

Check the connections

YES

between IC501 and IC521.

YES

Check IC521.

YES

Check IC501.

Check the connections of CD8V power supply.

(No.MA266)1-11

5.3 Spindle section

Is the disk rotated?

Is the voltage output at pin 6 and pin 7 of IC501?

Is the voltage input at pin 17 of IC501?

Is the voltage output at pin 5 of IC521?

Is the power supply present at pin 37, pin 49, pin 53, pin 56 and pin 72 of IC521?

YES

Does the RF signal appear at pin 39 of IC521?

YES

Check the spindle motor and its wiring.

Is the power supply

YES

present at pin 3, pin 12 and pin 21 of IC501?

Check the connections of CD8V power supply.

Check the connections

YES

between IC501 and IC521.

YES

Check IC521.

YES

Is the RF waveform at pin 39 of IC521 distorted?

Check the circuits in the vicinity of IC521 or the pickup.

YES

NONO

Check IC501.

YES

Proceed to the Tracking section

Check the connections of CD8V power supply.

5.4 Tracking section

When the disc is rotated at first:

Approx. 1.2V

Is the tracking error signal output at pin 26 of IC521?

Check the pickup and its connections.

Replace IC521 or repair

YES

the malfunction connection point

1-12 (No.MA266)

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