JVC KD-SX777 Service Manual

SERVICE MANUAL

CD RECEIVER

KD-SX777

Contents

Safety precaution------------------------------------- 1-2

Preventing static electricity Disassembly method Adjustment method

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1-3 1-4

1-9

Area Suffix

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UR Brazil

Flow of functional operation unit TOC read----

Maintenance of laser pickup----------------------- 1-12 Replacement of laser pickup ---------------------- 1-12 Description of major ICs ---------------------------- 1-13

1-10

No.49636

APR. 2001

KD-SX777

Safety precaution

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.

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

1-2

KD-SX777

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.

1.1. Grounding to prevent damage by static electricity

Static electricity in the work area can destroy the optical pickup (laser diode) in devices such as DVD players. Be careful to use proper grounding in the area where repairs are being performed.

1.1.1. Ground the workbench

1. 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.

1.1.2. Ground yourself

1. 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

1.1.3. 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.

1.2. 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

Shorted part

1-3

KD-SX777

Disassembly method

Removing the front chassis (See Fig.1)

1. Remove two screws A and insert a screwdriver to the joints a on the side of the front chassis and two joints b on the right side, then detach the front chassis toward the front side.

Removing the heat sink (See Fig.2 )

1. Remove the three screws B attaching the heat sink on the left side of the body, and remove the heat sink.

Front chassis

Fig.1

Removing the bottom cover (See Fig.3 )

1.2.Turn the body upside down. Insert a screwdriver to the two joints c and two joints d on

both sides of the body and the joint e on the back of the body, then detach the bottom cover from the body.

Heat sink

Fig.2

Regulator board

Fig. 3

1-4

KD-SX777

Removing the main amplifier board assembly

(See Fig.4 and 5)

Remove the front chassis.

Remove the bottom cover.

Remove the two screws C attaching the main amplifier board assembly on the bottom of the body.

Remove the three screws D attaching the main amplifier board assembly on the back of the body.

Disconnect connector CN501 on the main amplifier board

5. assembly from the CD mechanism assembly.

Main amplifier board

CN501

Fig.4

Fig. 5

Removing the CD mechanism assembly

(See

Fig.6 )

Remove the front chassis.

1. Remove the bottom cover.

2. Remove the main amplifier board assembly.

3. Remove the three screws E attaching the CD mechanism

4. assembly from the top cover.

Removing the control switch board

(See

Fig.7 and 8 )

Remove the front chassis.

Remove the four screws F attaching the rear cover on the back of the front panel unit.

Remove the control switch board from the front panel

3. unit.

CD mechanism assembly

Top cover

Control switch board

Fig. 6

Fig. 7

Fig. 8

1-5

KD-SX777

Removing the CD mechanism control board(See Fig.1 and 2)

Unsolder the part f and g on the CD mechanism control board.

Remove the stator fixing the CD mechanism control board and the damper bracket (To remove the stator smoothly, pick up the center part).

Remove the screw F attaching the CD mechanism control board.

Remove the CD mechanism control board in the direction of the arrow while releasing it from the two damper bracket slots i and the front bracket slot j.

Disconnect the flexible wire from connector on the pickup unit.

ATTENTION:

Turn the FD gear in the direction of the arrow to move the entire pickup unit to the appropriate position where the flexible wire of the CD mechanism unit can be disconnected easily (Refer to Fig.2).

CD mechanism ass’y

Front bracket

Damper bracket

Fig.1

Pickup unit

Flexible wire

CD mechanism control board

Shift the lock

FD gear

Loading motor

Pull outward

Fig.2

CD mechanism control board

Front bracket

Fig.3

Front bracket

Pull outward

1-6

Flame

Fig.4

KD-SX777

Removing the loading motor

(See Fig.3 to 5)

Prior to performing the following procedure, remove the CD mechanism control board.

Remove the two springs k attaching the CD mechanism ass’y and the front bracket.

Remove the two screws G and the front bracket while pulling the flame outward.

Remove the belt and the screw H from the loading motor.

Removing the CD mechanism ass’y

(See Fig.1, 6 to 9)

CD mechanism ass’y

Flame

Loading motor

Belt

Fig.5

Damper bracket

Fig.6

Prior to performing the following procedure, remove the CD mechanism control PWB and the front bracket (loading motor).

Remove the three screws I and the damper bracket.

Raise the both sides fix arms and move the fix plates in the direction of the arrow to place the four shafts l as shown in Fig.8 and 9.

Remove the CD mechanism ass’y and the two springs m attaching the flame.

Remove the two screws J and both sides rear damper brackets from the dampers. Detach the CD mechanism ass’y from the left side to the right side.

ATTENTION:

The CD mechanism ass’y can be removed if only the rear damper bracket on the left side is removed.

Fix plate (L)

Fix arm (R)

Fig.7

Rear damper bracket

Fig.8

Rear damper bracket

Fix plate(R)

Fix arm (L)

Damper

Fig.9

1-7

KD-SX777

Removing the feed motor ass’y

(See Fig.10)

Prior to performing the following procedure, remove the CD mechanism control board, the front bracket (loading motor) and the CD mechanism ass’y.

Remove the two screws K and the feed motor ass’y.

Removing the pickup unit

(See Fig.10 and 11)

*Prior to performing the following procedure, remove the CD mechanism control board, the front bracket (loading motor), the CD mechanism ass’y and the feed motor ass’y.

Detach the FD gear part of the pickup unit upward. Then remove the pickup unit while pulling out the part n of the FD screw.

Feed motor ass’y

FD gear

Nut push spring plate

FD screw

Pickup unit

Fig.10

Part n

Part O

Pickup unit

Pickup mount nut

Pickup unit

ATTENTION:

Remove the screw L attaching the nut push spring plate and the pickup mount nut from the pickup unit. Pull out the FD screw.

When reattaching the pickuap unit, reattach the part o of the pickup unit, then the part n of the FD screw.

Removing the spindle motor

(See Fig.12 and 13)

Prior to performing the following procedure, remove the CD mechanism control board, the front bracket (loading motor), the CD mechanism ass’y and the feed motor ass’y.

Turn up the CD mechanism ass’y and remove the two springs p on both sides of the clamper arms. Open the clamper arm upward.

Turn the turn table, and remove the two screws M and the spindle motor.

FD screw

Spindle motor

Fig.11

Fig.12

1-8

Fig.13

Adjustment method

KD-SX777

Test instruments required adjustment

1.Digital oscilloscope (100MHz)

2.AM Standard signal generator

3.FM Standard signal generator

4.Stereo modulator

5.Electric voltmeter

6.Digital tester

7.Tracking offset meter

8.Test Disc JVC : CTS-1000

9.Extension cable for check EXTGS004-26P

Standard measuring conditions Power supply voltage DC14.4V(10.5 Load impedance 4 (4 to 8 allowance) Line-out Level/Impedance KD-SX770 : 2.0 V/20k load(full scale) Output impedance : 1k

Standard volume position Balance and Bass & Treble volume : Indication "0" BBE : OFF

Frequency Band FM AM

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.

–

16V)

1 – 3 87.5MHz – 107.9MHz 530kHz – 1710kHz

How to connect the extension cable for adjusting

CN701

CN501

EXTGS004-26P

1-9

KD-SX777

Flow of functional operation unit TOC read

Power ON

When the pickup correctly moves to the inner area of the disc

Set Function CD

When the laser diode correctly

emits

Microprocessor commands

FMO TC9462"53"

FEED MOTOR +TERMINAL IC581"6"

REST SW

When correctly focused

FEO TA2109

Focus Servo Loop ON

$83

$82

$81

5V Hi-Z 0V

6V 4V 2V

OFF ON

Pickup feed to the inner area

2.2V

RF signal eye-pattern remains closed

RF signal eye-pattern opens

Disc inserted

YES

Laser emitted

Focus search

Disc rotates

Tracking loop closed

TOC readout

YES

Microprocessor commands

SEL TC9462

LD CN501

"No disc" display

When the disc correctly rotates

Microprocessor commands

DMO TC9462

Spindle motor(-) IC581"5"

$84 $86 $ A200

Acceleration Servo CLV

Rough Servo

0.5 Sec 0.5 Sec

$84

5V 0V

4V 0V

2.2V 0V

3.2 2V

1-10

Jump to the first track

Play

Tracking Servo Loop ON

RF signal

Rough Servo Mode

CLV Servo Mode (Program Area)

CLV Servo Mode (Lead-In Area; Digital: 0)

+ 21 hidden pages

JVC KD-SX777 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

KD-SX777

Safety precaution

Preventing static electricity

Disassembly method

Adjustment method

Flow of functional operation unit TOC read