JVC MXKB-1, MXKB-2 Service manual

SERVICE MANUAL

COMPACT COMPONENT SYSTEM

MB28420048

MX-KB2,MX-KB1

Area suffix

UW ----------- Brazil,Mexico,Peru

TABLE OF CONTENTS

1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

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

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

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31

COPYRIGHT © 2004 Victor Company of Japan, Limited

No.MB284

2004/8

SPECIFICATION

Amplifier Output Power 30 W per channel, min. RMS, driven into 6 Ω at 1kHz, with no more than

10% total harmonic distortion (IEC 268-3)

Input Sensitivity/Impedance (1 kHz) AUX IN:500 mV/51 kΩ
Speaker terminals 6 - 16 Ω
Phones 32 Ω - 1 kΩ

Cassette Deck Section Frequency Response 20 mW/ch output into 32 Ω

Type I (NORMAL) 63 Hz - 12 500 Hz

Wow And Flutter 0.15 % (WRMS)

CD Player CD Capacity 3 CDs

Dynamic Range 85 dB

Signal-To-Noise Ratio 85 dB

Wow And Flutter Unmeasurable

Tuner FM Tuner 87.5 MHz - 108.0 MHz

AM Tuner 530 kHz - 1710 kHz (at AM10 kHz channel space)

531 kHz - 1710 kHz (at AM9 kHz channel space)

Unit Dimensions 276 mm × 315 mm × 456 mm (W/H/D)

Mass Approx. 8 kg

Speaker Specifications
SP-MXKB2/SP­MXKB1 (each unit)

Power Specifications Power Requirements AC 110/127/220/230-240V , adjustable with voltage selector, 50/60 Hz

Type 2-way bass-reflex type

Speaker Unit Woofer : 13 cm cone × 1

Tweeter : 5cm cone × 1

Power Handling Capacity 30 W

Impedance 6 Ω

Frequency Range 65 Hz - 20,000 Hz

Sound pressure level 86 dB/W·m

Dimensions 208 mm × 323 mm × 264 mm (W/H/D)

Power Consumption 83 W (power on mode) 13 W (in Standby mode)

Design and specifications are subject to change without notice.

1-2 (No.MB284)

SECTION 1

PRECAUTION

1.1 Safety Precautions

(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 manufacturers 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 reassem­bling.

(5) Leakage shock hazard testing

After reassembling 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, 1,000Ω per volt or more sensitivity
in the following manner. Connect a 1,500Ω 10W resistor
paralleled by a 0.15µF AC-type capacitor between an ex-

posed 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 measure 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.).

AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)

0.15 F AC TYPE

Place this
probe on

1500 10W

Good earth ground

1.2 Warning

(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.

1.3 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.

1.4 Critical parts for safety

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. When replacing them, be sure to use the parts of the
same type and rating as specified by the manufacturer.
(This regulation dose not Except the J and C version)

each exposed
metal part.

(No.MB284)1-3

1.5 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.

1.5.1 Grounding to prevent damage by static electricity

Static electricity in the work area can destroy the optical pickup (laser diode) in devices such as laser products.
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

1M

Conductive material
(conductive sheet) or iron palate

(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.

1.6 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.

1.7 Attention when traverse unit is decomposed

*Please refer to "Disassembly method" in the text for the pickup unit.

• Apply solder to the short land sections before the flexible wire is disconnected from the connecto on the servo board. (If the flexible
wire is disconnected without applying solder, the pickup may be destroyed by static electricity.)

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

Card wire

1-4 (No.MB284)

CD pickup board

Short-circuit point

1.8 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

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

CLASS 1
LASER PRODUCT

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

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

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

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)

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

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

(No.MB284)1-5

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.

1-6 (No.MB284)

SECTION 3

DISASSEMBLY

3.1 Main body

3.1.1 Removing the top cover / side cover (R) and (L)
(See Fig.1 to 6)

(1) From the back of the body, remove the two screws A at-

taching the top cover.

(2) From both sides of the body, remove the four screws B at-

taching the top cover and the side cover (R) and (L). Move
the top cover in the direction of the arrow to release from
the front panel at the two joints a.

(3) Remove the six screws D on the back of the body and the

two screws E on the side of the body. Move the side cover
(R) and (L) backward to release the four joints b on the bot­tom of the side covers.

A

Top cover

A

B

Front panel assembly

a

Fig.1

Fig.2

Top cover

B

Side cover (R)

(No.MB284)1-7

D D

Side cover (L)

Front panel assembly

Side cover (R)

Front panel assembly

E

Fig.3

b

Fig.4

Side cover (L)

Side cover (R)

b

E

Fig.5

Joint b

Fig.6

1-8 (No.MB284)

3.1.2 Removing the CD fitting
(See Fig.7 to 9)

• Prior to performing the following procedure, remove the top

cover / side cover (R) and (L).

Caution:

For preventing from damage, make sure to remove the CD fit­ting before detaching the CD changer mechanism unit.
(1) Push STANDBY / ON key to turn power on.
(2) Push CD TRAY EJECT key.
(3) Move the CD fitting in the direction of the arrow to release

from the CD tray at two joints d.

(4) Push STANDBY / ON key to close the tray.

3.1.3 Removing the CD fitting
(See Fig.8 to 10)

< How to eject the CD tray without turning power on >

• Prior to performing the following procedure, remove the top

cover / side cover(R) and (L).
(1) Turn over the CD changer mechanism unit and turn the

loading pulley gear at e in the inner part of the notch of the
main board to move the CD tray forward.

(2) Move the CD fitting in the direction of the arrow to release

from the CD tray at two joint d.

(3) Manually push and close the CD tray.

CD changer mechanism unit

CD fitting

d

CD tray

CD fitting

Fig.8

CD tray

STANDBY / ON

Front panel assembly

CD TRAY EJECT

Fig.9

CD changer mechanism

Main board

Fig.7

Loading pullygear

Fig.10

e

(No.MB284)1-9

3.1.4 Removing the CD changer mechanism unit
(See Fig.11 to 16)

• Prior to performing the following procedure, remove the top

cover / side cover (R) and (L), and the CD fitting.
(1) Disconnect the wire from connector CN601 on the turner

board on the right side of the body.

(2) Disconnect the wire from connector CN504

board on the inner side of the front panel.

(3) Disconnect the wire from connector CN801

on the power board.

CN803

(4) Disconnect the wire from connector CN100, CN101 and

on the main board at the bottom of the CD changer

CN207

mechanism unit, and disconnect the card wire from con­nector CN103
wires.

(5) From the side of the body, remove the two screws F attach-

ing the CD changer mechanism unit.

(6) From the back of the body, remove the two screws G at-

taching the CD changer mechanism unit.

(7) Move the CD changer mechanism unit in the direction of

the arrow while pulling the rear panel backward, and re­move the CD changer mechanism unit.

. If necessary, release the band attaching the

on the AUX

, CN802 and

CD changer mechanism unit

F

AUX board
CN504

Front panel assembly

Rear panel

Rear panel

Turner board
CN601

Fig.11

CD changer mechanism unit

Front panel assembly

Fig.12

F

1-10 (No.MB284)

AUX board
CN504

CD changer mechanism unit

Main board

Front panel assembly

CD changer mechanism unit

Fig.13

CN801

G

CN100

CN207

Fig.15

Rear panel

CN103

CN101

G

CN802

Fig.16

Power board

CN803

Fig.14

(No.MB284)1-11

3.1.5 Removing the tuner board
(See Fig.17, 18)

• Prior to performing the following procedure, remove the top

cover / side cover (R) and (L).
(1) Disconnect the wire from connector CN601 on the tuner

board.

(2) From the back of the body, remove the two screws H, the

two screws J and the two screws K attaching the tuner
board respectively.

(3) Remove the two screws L attaching the tuner board holder.

Caution:

You can remove the tuner board without removing the CD
changer mechanism unit and the rear panel.

H

K

J

Tuner board
CN601

Fig.17

Tuner board holder

L

1-12 (No.MB284)

Tuner board

Fig.18

3.1.6 Removing the speaker terminal board

(See Fig.19, 20)

• Prior to performing the following procedure, remove the top

cover / side cover (R) and (L).
(1) Disconnect the wire from connector CN901

terminal board.

(2) From the back of the body, remove the two screws M at-

taching the speaker terminal board.

Reference:

You can remove the speaker terminal board without detaching
the CD changer mechanism unit and the rear panel.

on the speaker

Speaker terminal board

Rear panel

CN901

Fig.19

Rear cover

M

Rear panel

Fig.20

(No.MB284)1-13

3.1.7 Removing the front panel assembly
(See Fig.21 to 24)

• Prior to performing the following procedure, remove the top

cover / side cover (R) and (L), the CD fitting / CD changer
mechanism unit.
(1) Disconnect the wire from connector CN861

board.

(2) Disconnect the earth wire from the base chassis on the bot-

tom of the right side of the body.

(3) From the bottom of the body, remove the two screws N at-

taching the front panel assembly.

(4) Release the two joints f on the side of the body and the joint

g on the bottom using a screwdriver, and remove the front
panel assembly forward.

on the power

Rear panel

Power board

CN861

Fig.21

Front panel assembly

1-14 (No.MB284)

f

Earth wire

Fig.22

Front panel assembly

Fig.23

Front panel assembly

f

N

N

Fig.24

(No.MB284)1-15

3.1.8 Removing the POWER switch board / CD switch board
(See Fig.25, 26)

• Prior to performing the following procedure, remove the front

panel assembly.
(1) Remove the two screws P and the three screws Q attach-

ing the bracket.
(2) Remove the screws R attaching the POWER switch board.
(3) Remove the screw T attaching the CD switch board.

P

Q

Front panel assembly

Fig.25

Bracket

P

CD switch boardPower switch board

RT

3.1.9 Removing the REC select switch board / PROGRAM select switch board
(See Fig.27)

• Prior to performing the following procedure, remove the front

panel assembly.
(1) Remove the three screws U attaching the REC select

switch board.

(2) Remove the three screws Y attaching the CD switch board.

Y

PROGRAM select
switch boaed

Front panel assembly

Fig.26

Front panel assembly

Y

Fig.27

U

U

REC select
switch boaed

1-16 (No.MB284)

3.1.10 Removing the LCD board / STANDBY board

(See Fig.28, 29)

• Prior to performing the following procedure, remove the front

panel assembly.
(1) Remove the four screws A’ attaching the LCD board and

disconnect the wire from connector CN505

(2) Remove the two screws B’ attaching the STANDBY board.

.

Front panel assembly

A'

CN505

LCD board

Front panel assembly

A'

Fig.28

STANDBY board

B'

Fig.29

(No.MB284)1-17

3.1.11 Removing the system board / headphone board / AUX board
(See Fig.30 to 34)

• Prior to performing the following procedure, remove the front

panel assembly.
(1) Pull out the volume knob on the front side of the front panel

assembly. Release the three tabs of the knob holder and

pull out the knob holder.
(2) Remove the nut and the washer from the volume shaft.
(3) From the back of the front panel assembly, remove the sev-

enteen screws D’ attaching the system board.
(4) Remove the screw E’ attaching the headphone board fit-

ting plate and pull out the headphone board.
(5) Remove the screw F’ attaching the AUX board fitting plate

and pull out the AUX board.

Washer

Nut

Volume knob

Front panel assembly

Knob holder

Ta b

Fig.30

Front panel assembly

D'

1-18 (No.MB284)

D'

System board

D'

D'

Fig.31

Front panel assembly

Cassette mechanism assembly

G'

Headphone board

Fig.32

Front panel assembly

E'

Fitting plate

Front panel assembly

G'

Fig.34

F'

Fitting plate

AUX board

Fig.33

(No.MB284)1-19

3.1.12 Removing the cassette mechanism assembly
(See Fig.35)

• Prior to performing the following procedure, remove the front

panel assembly.
(1) Remove the six screws G’ attaching the cassette mecha-

nism assembly.

Rear cover

H' H'

H'

Rear panel

Fig.35

H'

1-20 (No.MB284)

3.1.13 Removing the rear cover / rear panel

(See Fig.36 to 38)

• Prior to performing the following procedure, remove the top

cover / side cover (R) and (L), the CD fitting / CD changer
mechanism unit.
(1) From the back of the body, remove the four screws H’ at-

taching the rear cover.

(2) From the back of the body, remove the two screws J’ at-

taching the rear panel.

(3) Release the two joints h on the bottom of the right and left

sides of the rear panel, and remove the rear panel. The
rear panel comes off with the power board and the heat
sink.

Rear panel

J'

Fig.36

Rear panel

h

Fig.37

Raer panel

h

Fig.38

(No.MB284)1-21

3.1.14 Removing the heat sink / power board
(See Fig.39 to 42)

• Prior to performing the following procedure, remove the top

cover / side cover (R) and (L), the CD fitting / CD changer
mechanism unit, the rear cover / rear panel.
(1) From the inner side of the rear panel, remove the four

screws K’ attaching the heat sink. Move the heat sink in the
direction of the arrow along the notch of rear panel and re­move it with the heat sink and the power board forward.

(2) Remove the four screws M’ and the four screws N’ attach-

ing the board bracket (R) and (L).

(3) Remove the two screws P’ and the two screws Q’ attaching

the power board.

(4) If necessary, unsolder the power cord and the wire extend-

ing from the power transformer assembly.

Raer panel

P'

Heat sink

Q'

M'

Board bracket (R)

M'

Board bracket (L)

Power board

Fig.41

Board bracket (R) Board bracket (L)

Heat sink

K'

Raer panel

Fig.39

Power board

N' N'

K'

Power board

Soldered parts

Fig.42

Heat sink

1-22 (No.MB284)

Power board

Fig.40