Jvc KDS 621 Service Manual

Page 1

JVB

SERVICE MANUAL

CD RECEIVER

KD-S621

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DIGITAL AUDIO
Area Suffix
E -------- Continental Europe
EX ------------ Central Europe
Contents
Safety precaution ------------------------ 1-2 Flow of functional
Preventing static electricity ------------ 1-3 operation unit TOC read ---------- 1-12
Disassembly method ------------------- 1-4 Maintenance of laser pickup ---------- 1-14
Adjustment method --------------------- 1-11 Replacement of laser pickup ---------- 1-14
Description of major ICs ----------------- 1-15~26

No.49675

COPYRIGHT © 2002 VICTOR COMPANY OF JAPAN, LTD.
Jan. 2002

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KD-8621

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

1M0

' 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.Hand|ing 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

Damper bracket

cn mechanism assy

Attention when traverse unit is decomposed

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

1.Solder is put up before the card wire is removed from connector on
the CD substrate as shown in Figure.
(When the wire is removed without putting up solder, the CD pick-up
assembly might destroy.) F'°b'a°ke
2.Please remove solder after connecting the card wire with
when you install picking up in the substrate.

1-3

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KD-8621

l Removing the feed motor assy
(See Fig.10)

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

1. Remove the two screws K and the feed motor assy.

l 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 assy and the
feed motor assy.

1. 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.

ATTENTION: When reattaching the pickuap unit,
reattach the part 0 of the pickup unit,
then the part n of the FD screw.

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

l 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 assy and the
feed motor assy.

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

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

1-10

FD screw Part n
Feed motor assy

FD gear Pickup unit
Fig.10

3- L
Nut push spring plate-<~L%

Pickup mount nut

Pickup unit

FD screw ,/3

Fig.12

Spindle motor M