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SERVICE MANUAL
COPYRIGHT © 2004 Victor Company of Japan, Limited
No.MB254
2004/7
COMPACT COMPONENT SYSTEM
MB254
2004
7
MX-KB4
TABLE OF CONTENTS
1
PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2
SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
4
ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
5
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
FM MODE
FM /AM
AUX
SLEEP
STANDBY/ON
CD
1
CD
2
CD
3
SOUND
MODE
RHYTHM AX
FADE
MUTING
VOLUME
PROGRAM /RANDOM
REPEAT
TAPE
A
CD
TAPE
B
REMOTE CONTROL
CA-MXKB4
SP-MXKB4
SP-MXKB4
Area suffix
UW ----------- Brazil,Mexico,Peru
UJ ---------------------- U.S.Military


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1-2 (No.MB254)
SPECIFICATION
Design and specifications are subject to change without notice.
Amplifier
Output Power
140 W per channel, min. RMS, driven into 6
at 1kHz, with no more than
10% total harmonic distortion (IEC 268-3)
Input
Sensitivity/Impedance
(1 kHz)
AUX IN:400 mV/50 k
Speaker terminals
6 - 16
Phones
32
- 1 k
Cassette Deck
Frequency Response
15 mW/ch output into 32
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 Tuning Range
87.50 - 108.00 MHz (at AM9 kHz channel space)
87.5 - 108.0 MHz (at AM10 kHz channel space)
AM Tuner Tuning Range
531 kHz - 1710 kHz (at AM9 kHz channel space)
530 kHz - 1710 kHz (at AM10 kHz channel space)
Unit
Dimensions
270 mm
× 306 mm × 456 mm (W/H/D)
Mass
Approx. 8.6 kg
Speaker Specifications
SP-MXKB4 (each unit)
Type
3-way bass-reflex type
Speaker Unit
Woofer:20 cm cone
× 1
Mid:5cm cone
× 1
Tweeter:2 cm dome
× 1
Power Handling Capacity
140 W
Impedance
6
Frequency Range
45 Hz - 22,000 Hz
Sound pressure level
87 dB/W·m
Dimensions
257 mm
× 321 mm × 261 mm (W/H/D)
Mass
Approx. 4.9 kg
Power Specifications
Power Requirements
AC 110/127/220/230-240V , adjustable with voltage selector, 50/60 Hz
Power Consumption
140 W (power on mode) 22 W (in Standby mode)


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(No.MB254)1-3
SECTION 1
PRECAUTION
1.1
Safety Precautions
(1) This design of this product contains special hardware and
many circuits and components specially for safety purpos-
es. 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 per-
formed 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 characteris-
tics are often not evident from visual inspection nor can the
protection afforded by them necessarily be obtained by us-
ing replacement components rated for higher voltage, watt-
age, etc. Replacement parts which have these special
safety characteristics are identified in the Parts List of Ser-
vice 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 charac-
teristics 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 reassem-
bling.
(5) Leakage shock hazard testing
After reassembling the product, always perform an isola-
tion check on the exposed metal parts of the product (an-
tenna 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, particular-
ly any exposed metal part having a return path to the
chassis, to a known good earth ground. Any leakage cur-
rent 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, 1,000
per volt or more sensitivity
in the following manner. Connect a 1,500
10W resistor
paralleled by a 0.15
µF 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.).
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 pre-
forming 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)
Good earth ground
Place this
probe on
each exposed
metal part.
AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)
1500
10W
0.15 F AC TYPE


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1-4 (No.MB254)
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.
(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.
1M
Conductive material
(conductive sheet) or iron palate
(caption)
Anti-static wrist strap
CD PCB
Short round
CN601


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(No.MB254)1-5
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.
REPRODUCTION AND POSITION OF LABELS
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)
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)
!
Please use enough caution not to
see the beam directly or touch it
in case of an adjustment or operation
check.
CLASS 1
LASER PRODUCT
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)
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)
WARNING LABEL