Jvc KD-S795 Service Manual

49789200302

KD-S795

SERVICE MANUAL

CD RECEIVER

KD-S795

COMPACT

DIGITAL AUDIO

Area Suffix

U ----------- Other Areas

TABLE OF CONTENTS

1 Important Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4

3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23

4 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27

No.49789

2003/02

KD-S795

1.1 Safety Precautions

SECTION 1

Important Safety 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.

1-2 (No.49789)

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 DVD 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

KD-S795

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) I t 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 CDpickup may be destroyed by static electricity.)

• In the assembly, be sure to remove solder from the short land after connecting the flexible wire.

Short-circuit point

(Soldering)

Flexible wire

Short-circuit point

Pickup

(No.49789)1-3

KD-S795

2.1 Main body

2.1.1 Removing the front panel assembly (See Fig.1)

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

panel assembly and remove the front panel assembly in the direction of the arrow.

SECTION 2

Disassembly method

Front panel assembly

2.1.2 Removing the front chassis assembly (See Figs.2 to 4)

• Prior to performing the following procedure, remove the front

panel assembly. (1) Remove the screw A on the both sides of the main body,

and two screws B on the front chassis assembly.

(2) Release the two joints a and two joints b on both sides

of the main body using a screwdriver, and remove the front chassis assembly forward.

Detach button

Fig.1

Joint a

Front chassis assembly

Fig.2

Joint b

1-4 (No.49789)

Joint b

Front chassis assembly

Fig.3

Fig.4

2.1.3 Removing the heat sink

(See Fig.5)

(1) Remove the two screws C and two screws D on the left

side of the main body.

KD-S795

2.1.4 Removing the bottom cover

(See Figs.6 and 7)

• Prior to performing the following procedure, remove the front

panel assembly, front chassis assembly and heat sink. (1) Turn over the body and release the two joints c, two joints

d and joint e .

CAUTION:

Do not damage the main board when releasing the joint e using a screwdriver. (See Figs.6 and 7)

Joint c

Joint e

Heat sink

Fig.5

Bottom cover

Joint d

Fig.6

Joint d

Bottom cover

2.1.5 Removing the rear bracket

(See Fig.8)

• Prior to performing the following procedure, remove the front

panel assembly, front chassis assembly, heat sink and bottom cover. (1) Remove the three screws E, three screws F and two

screws G on the back of the body.

(2) Remove the rear bracket.

Joint e

Joint c

Rear bracket

Fig.7

Fig.8

(No.49789)1-5

KD-S795

2.1.6 Removing the main board (See Fig.9)

• Prior to performing the following procedure, remove the front

panel assembly, front chassis assembly, heat sink, bottom cover and rear bracket. (1) Remove the two screws H attaching the main board. (2) Disconnect connector CN501 and remove the main board.

2.1.7 Removing the CD mechanism assembly (See Fig.10)

• Prior to performing the following procedure, remove the front

panel assembly, front chassis assembly, heat sink, bottom cover, rear bracket and main board. (1) Remove the three screws J .

CN501

Main board

Fig.9

CD mechanism assembly

Top chassis

Fig.10

1-6 (No.49789)

2.1.8 Removing the front board

(See Figs.11 to 13)

• Prior to performing the following procedure, remove the front

panel assembly. (1) Remove the four screws K on the back side of the front

panel assembly. (2) Release the ten joints f . (3) Take out the front board.

KD-S795

Fig.11

Joint f

Joint

Joint f

Front board

Fig.12

Joint f

Fig.13

(No.49789)1-7

KD-S795

2.2 CD Mechanism Assembly

2.2.1 Removing the top cover (See Figs.1 and 2)

(1) Remove the two screws A on the both side of the body. (2) Lift the front side of the top cover and move the top cover

backward to release the two joints a.

Top cover

Joints a

Fig.1

Top cover

Fig.2

1-8 (No.49789)

KD-S795

2.2.2 Removing the connector board

(See Figs.3 to 5)

CAUTION:

Before disconnecting the flexible wire from the pickup, solder the short-circuit point on the pickup. No observance of this instruction may cause damage of the pickup. (1) Remove the screw B fixing the connector board. (2) Solder the short-circuit point on the connector board. (3) Disconnect the flexible wire from the pickup. (4) Move the connector board in the direction of the arrow to

release the two joints b.

(5) Unsolder the wire on the connector board if necessary.

CAUTION:

Unsolder the short-circuit point after reassembling.

Connector board

Flexible wire

Wires

Joints b

Short-circuit point

Fig.3

Short-circuit point

(Soldering)

Pickup

Flexible wire

Frame

Pickup

Fig.4

Connector board

Fig.5

(No.49789)1-9

KD-S795

2.2.3 Removing the DET switch (See Figs.6 and 7)

(1) Extend the two tabs c of the feed sw. holder and pull out

the switch.

(2) Unsolder the DET switch wire if necessary.

DET switch

Connector board

Pickup

Fig.6

DET switch

Tab c

DET switch wire

Feed sw. holder

Fig.7

1-10 (No.49789)

2.2.4 Removing the chassis unit

(See Figs.8 and 9)

• Prior to performing the following procedure, remove the top

cover and connector board. (1) Remove the two suspension springs (L) and (R) attaching

the chassis unit to the frame.

CAUTION:

• The shape of the suspension spring (L) and (R) are different. Handle them with care.

• When reassembling, make sure that the three shafts on the underside of the chassis unit are inserted to the dampers certainly.

Suspension spring (R)

KD-S795

Chassis unit

Suspension spring (L)

Frame

Suspension spring (R)

Chassis unit

Shafts

Damper

Suspension spring (L)

Fig.8

Shaft

Dampe

Frame

Fig.9

(No.49789)1-11

KD-S795

2.2.5 Removing the clamper assembly (See Figs.10 and 11)

• Prior to performing the following procedure, remove the top

cover. (1) Remove the clamper arm spring. (2) Move the clamper assembly in the direction of the arrow to

release the two joints d.

Clamper arm spring

Joint d

Clamper assembly

Fig.10

Clamper arm spring

Chassis rivet assembly

Joint d

Chassis rivet assembly

Clamper assembly

Joint d

Fig.11

1-12 (No.49789)

2.2.6 Removing the loading / feed motor assembly

(See Figs.12 and 13)

• Prior to performing the following procedure, remove the top

cover, connector board and chassis unit. (1) Remove the screw C and move the loading / feed motor

assembly in the direction of the arrow to remove it from the chassis rivet assembly.

(2) Disconnect the wire from the loading / feed motor assembly

if necessary.

CAUTION:

When reassembling, connect the wire from the loading / feed motor assembly to the flame as shown in Fig.12.

KD-S795

Loading / feed motor assembly

Fig.12

Loading / feed motor assembly

Fig.13

(No.49789)1-13

KD-S795

2.2.7 Removing the pickup unit (See Figs.14 to 18)

• Prior to performing the following procedure, remove the top

cover, connector board and chassis unit. (1) Remove the screw D and pull out the pu. shaft holder from

the pu. shaft. (2) Remove the screw E attaching the feed sw. holder. (3) Move the part e of the pickup unit upward with the pu. shaft

and the feed sw. holder, then release the joint f of the feed

sw. holder in the direction of the arrow. The joint g of the

pickup unit and the feed rack is released, and the feed sw.

holder comes off. (4) Remove the pu. shaft from the pickup unit. (5) Remove the screw F attaching the feed rack to the pickup

unit.

2.2.8 Reattaching the pickup unit (See Figs.14 to 17)

(1) Reattach the feed rack to the pickup unit using the screw F. (2) Reattach the feed sw. holder to the feed rack while setting

the joint g to the slot of the feed rack and setting the part f of the feed rack to the switch of the feed sw. holder correctly.

(3) As the feed sw. holder is temporarily attached to the pickup

unit, set to the gear of the joint g and to the bending part of the chassis (joint h) at a time.

CAUTION:

Make sure that the part i on the underside of the feed rack is certainly inserted to the slot j of the change lock

lever. (4) Reattach the feed sw. holder using the screw E. (5) Reattach the pu. shaft to the pickup unit. Reattach the pu.

shaft holder to the pu. shaft using the screw D.

Joint g

Feed sw. holder

Part e

Feed rack

Part i

Pickup unit

Slot j

Fig.15

Pu. shaft

Joint f

Joint h

Fig.16

Feed rack

Pickup unit

Feed sw. holder

Pu. shaft holder

Joint f

Pu. shaft

Pu. shaft holder

Feed sw. holder

Pickup unit

Fig.14

Part e

Joint g

Pickup unit

Feed rack

Fig.17

Pickup unit

Joint g

Joint f

Feed sw. holder

Fig.18

1-14 (No.49789)

KD-S795

2.2.9 Removing the trigger arm (See Figs.19 and 20)

• Prior to performing the following procedure, remove the top

cover, connector board and clamper unit. (1) Turn the trigger arm in the direction of the arrow to release

the joint k and pull out upward.

CAUTION:

When reassembling, insert the part m and n of the trigger arm into the part p and q at the slot of the chassis rivet assembly respectively and join the joint k at a time.

Chassis rivet assembly

Trigger arm

Chassis rivet assembly

Joint k

Trigger arm

Fig.19

Part p

Part q

Part m

Part n

2.2.10 Removing the top plate assembly (See Fig.21)

• Prior to performing the following procedure, remove the top

cover, connector board, chassis unit, and clamper assembly. (1) Remove the screw H. (2) Move the top plate assembly in the direction of the arrow to

release the two joints r.

(3) Unsolder the wire marked s if necessary.

Fig.20

Top plate assembly

Joints

Fig.21

(No.49789)1-15

KD-S795

2.2.11 Removing the mode sw. / select lock arm (See Figs.22 and 23)

• Prior to performing the following procedure, remove the top

plate assembly. (1) Bring up the mode sw. to release from the link plate (joint t)

and turn in the direction of the arrow to release the joint u. (2) Unsolder the wire of the mode sw. marked s if necessary. (3) Turn the select lock arm in the direction of the arrow to re-

lease the two joints v. (4) The select lock arm spring comes off the select lock arm at

the same time.

Top plate

Link plate

Joint u

Joint t

Fig.22

Select lock arm

Mode sw.

Select lock arm

Top plate

Hook w

Select lock arm spring

Link plate

Joints v

Fig.23

1-16 (No.49789)

KD-S795

2.2.12 Reassembling the mode sw. / select lock arm (See Figs.24 to 26)

REFERENCE:

Reverse the above removing procedure. (1) Reattach the select lock arm spring to the top plate and set

the shorter end of the select lock arm spring to the hook w on the top plate.

(2) Set the other longer end of the select lock arm spring to the

boss x on the underside of the select lock arm, and join the select lock arm to the slots (joint v). Turn the select lock arm as shown in the figure.

(3) Reattach the mode sw. while setting the part t to the first

peak of the link plate gear, and join the joint u.

CAUTION:

When reattaching the mode sw., check if the points y and z are correctly fitted and if each part operates properly.

Select lock arm spring

Hook w

Joint v

Select lock arm

Boss x

Fig.24

Joint t

Point y

Link plate

Point z

Link plate

Fig.25

Mode sw.

Select lock arm

Joint t

Joint u

Fig.26

(No.49789)1-17

KD-S795

2.2.13 Removing the select arm R / link plate (See Figs.27 and 28)

• Prior to performing the following procedure, remove the top

plate assembly. (1) Bring up the select arm R to release from the link plate

(joint a') and turn as shown in the figure to release the two joints b' and joint c'.

(2) Move the link plate in the direction of the arrow to release

the joint d'. Remove the link plate spring at the same time.

REFERENCE:

Before removing the link plate, remove the mode sw..

Select arm R

Joint b'

Link plate spring

Top plate

Joint c'

Joint a'

Link plate

Joint b'

Fig.27

Joint d'

Fig.28

Joint r

2.2.14 Reattaching the Select arm R / link plate (See Figs.29 and 30)

REFERENCE:

Reverse the above removing procedure. (1) Reattach the link plate spring. (2) Reattach the link plate to the link plate spring while joining

them at joint d'.

(3) Reattach the joint a' of the select arm R to the first peak of

the link plate while joining the two joints b' with the slots. Then turn the select arm R as shown in the figure. The top plate is joined to the joint c'.

CAUTION:

When reattaching the select arm R, check if the points e' and f' are correctly fitted and if each part operates properly.

Select arm R

Joint b'

Joint a'

Link plate spring

Joint c'

Joint d'

Joint b'

Joint a'

Fig.29

Link plate

1-18 (No.49789)

Point e'

Point f'

Fig.30

KD-S795

2.2.15 Removing the loading roller assembly

(See Figs.31 to 33)

• Prior to performing the following procedure, remove the

clamper assembly and top plate assembly. (1) Push inward the loading roller assembly on the gear side

and detach it upward from the slot of the joint g' of the lock arm rivet assembly.

(2) Detach the loading roller assembly from the slot of the joint

h' of the lock arm rivet assembly.

The roller guide comes off the gear section of the loading roller assembly.

Remove the roller guide and the HL washer from the shaft

of the loading roller assembly. (3) Remove the screw J attaching the lock arm rivet assembly. (4) Push the shaft at the joint i' of the lock arm rivet assembly

inward to release the lock arm rivet assembly from the slot

of the L side plate. (5) Extend the lock arm rivet assembly outward and release

the joint j' from the boss of the chassis rivet assembly. The

roller guide springs on both sides come off at the same

time.

CAUTION:

When reassembling, reattach the left and right roller guide springs to the lock arm rivet assembly before reattaching the lock arm rivet assembly to the chassis rivet assembly. Make sure to fit the part k' of the roller guide spring inside of the roller guide. (Refer to Fig.34.)

Roller guide spring

Part k'

Chassis rivet assembly

Loading roller assembly

Roller guide spring

Fig.32

Boss

Roller guide

Joint h'

Roller guide spring

Loading roller assembly

HL washer

Loading roller assembly

Joint g'

Lock arm rivet assembly

Fig.31

Roller guide

Roller guide spring

Lock arm rivet assembly

Part j'

Fig.33

Roller guide

HL washer

Loading roller

Roller guide spring

Fig.34

L side plate

Roller guide spring

Joint i'

Roller shaft assembly

(No.49789)1-19

KD-S795

2.2.16 Removing the loading gear 5, 6 and 7 (See Figs.35 and 36)

• Prior to performing the following procedure, remove the top

cover, chassis unit, pickup unit and top plate assembly. (1) Remove the screw K attaching the loading gear bracket.

The loading gear 6 and 7 come off the loading gear bracket.

(2) Pull out the loading gear 5.

Loading gear 5

Loading gear bracket

Loading gear 6

Loading gear 5

Loading gear 3

Fig.35

Loading gear bracket

Loading gear 6

Loading gear 7

1-20 (No.49789)

Fig.36

KD-S795

2.2.17 Removing the gears

(See Figs.37 to 40)

• Prior to performing the following procedure, remove the top

cover, chassis unit, top plate assembly and pickup unit.

• Pull out the loading gear 3. (See Fig.35.)

(1) Pull out the feed gear. (2) Move the loading plate assembly in the direction of the ar-

row to release the L side plate from the two slots m' of the chassis rivet assembly. (See Fig.37.)

(3) Detach the loading plate assembly upward from the chas-

sis rivet assembly while releasing the joint n'. Remove the slide hook and loading plate spring from the loading plate assembly.

(4) Pull out the loading gear 2 and remove the change lock le-

ver.

(5) Remove the E ring and washer attaching the changer gear

(6) The changer gear 2, change gear spring and adjusting

washer come off. (7) Remove the loading gear 1. (8) Move the change plate rivet assembly in the direction of the

arrow to release from the three shafts of the chassis rivet

assembly upward. (See Fig.38.) (9) Detach the loading gear plate rivet assembly from the shaft

of the chassis rivet assembly upward while releasing the

joint p'. (See Figs.38 and 40.)

(10) Pull out the loading gear 4.

Change plate rivet assembly

Shafts

E ring

Loading plate assembly

Loading plate spring

Joint p'

Loading gear 4

Loading gear plate rivet assembly

Shaft

Loading gear 2

Loading gear 1

Chassis rivet assembly

Change gear 2

Fig.38

Joint n'

Slide hook

Feed gear

Fig.37

Slot m'

L side plate

Loading plate assembly

Joint n'

Slot m'

Chassis rivet assembly

E ring

Washer

Change gear 2

Change gear spring

Adjusting washer

Change plate

rivet assembly

Chassis rivet assembly

L side plate

Slot m'

Fig.39

Loading gear 1

Loading gear 2

Change lock lever

Loading gear 4

Loading gear plate rivet assembly

Fig.40

(No.49789)1-21

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