JVC MXKB-4 Service manual
SERVICE MANUAL
COMPACT COMPONENT SYSTEM
MB19620045
MX-KB4
Area suffix
J ---------------------------- U.S.A.
C ------------------------- Canada
STANDBY/ON
SLEEP
AUX
FM /AM
FM MODE
CD
CD1CD2CD
3
PROGRAM/RANDOM
REPEAT
TAPE
TAPE
A
B
SOUND
VOLUME
MODE
FADE
MUTING
RHYTHM AX
REMOTE CONTROL
CA-MXKB4SP-MXKB4 SP-MXKB4
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
COPYRIGHT © 2004 VICTOR COMPANY OF JAPAN, LIMITED
No.MB196
2004/6
SPECIFICATION
Amplifier Output Power 180 W per channel, min. RMS, driven into 6 Ω at 1kHz, with no more
than 10% total harmonic distortion
Input Sensitivity/Impedance (1 kHz) AUX IN:400 mV/50 kΩ
Speaker terminals 6 - 16 Ω
Phones 32 Ω - 1 kΩ
Cassette Deck Frequency Response 15 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 Tuning Range:87.5 MHz - 108.0 MHz
AM Tuner Tuning Range:530 kHz - 1 710 kHz
Unit Dimensions 270 mm × 306 mm × 456 mm (W/H/D) (10-11/16" × 12-1/16" × 18")
Mass Approx. 8.6 kg (19.0 lbs)
Speaker Specifications
SP-MXKB4 (each unit)
Power Specifications Power Requirements AC 120 V , 60 Hz
Type 3-way bass-reflex type
Speaker Unit Woofer:20 cm (7-7/8") cone × 1
Mid:5cm (2") cone × 1
Tweeter:2 cm (13/16") dome × 1
Power Handling Capacity 180 W
Impedance 6 Ω
Frequency Range 45 Hz - 22,000 Hz
Sound pressure level 87 dB/W·m
Dimensions 257 mm × 321 mm × 261 mm (W/H/D) (10-1/8" × 12-11/16" × 10-5/16")
Mass Approx. 4.9 kg (10.9 lbs)
Power Consumption 150 W (power on mode)
22 W (in Standby mode)
Design and specifications are subject to change without notice.
1-2 (No.MB196)
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.MB196)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.
CD changer
unit
1-4 (No.MB196)
Flexible cable
Soldering
1.8 Importance administering point on the safety
Caution: For continued protection against risk of
fire, replace only with same type 3.5A/125V for
F901 and 1.6A/250V for F902.
This symbol specifies type of fast operating fuse.
Precaution: Pour eviter risques de feux, remplacez
le fusible de surete de F901 comme le meme type
que 3.5A/125V et 1.6A/250V pour F902.
Ce sont des fusibles suretes qui functionnes rapide.
^
(No.MB196)1-5
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.
1-6 (No.MB196)
SECTION 3
DISASSEMBLY
3.1 Disassembly of the main blocks of the set
Replacement of the fuses and the power IC
3.1.1 Replacing the fuses
(See Fig.1)
• Prior to performing the following procedure, remove the left
side board.
(1) Replace the fuses inside.
Caution:
Be sure to use fuses with the specified ratings.
3.1.2 Replacing the power IC
(See Fig.2)
• Prior to performing the following procedure, remove the top
cover.
(1) Remove the two screws A from the heat sink between the
power IC.
(2) Remove the solder fixing the power IC.
Fuse (F902)
1.6A 250V
Fig.1
W
Fuse (F901)
3.5A 125V
A
3.1.3 Replacing the heat sink cover
(See Fig.3)
(1) Remove four screws B from the rear panel.
(2) Pull the heat sink cover outward.
Fig.2
B
Fig.3
(No.MB196)1-7
3.1.4 Removing the top cover
(See Fig.4 and 5)
(1) Remove six screws C that retain the top cover from the
panel rear of the body.
(2) Remove six screws D that retain the top cover from the two
sides of the body.
(3) Remove the top cover from the body by lifting it toward the
rear.
Top cover
C
CC
Fig.4
Right Front panel assembly
D
D
Left Front panel assembly
D
D
Fig.5
1-8 (No.MB196)
3.1.5 Removing the CD changer unit
(See Fig.6 to 9)
• Prior to performing the following procedures, remove the top
cover.
Caution:
Although the CD mechanism unit can be removed without removing the CD tray panel, it is still recommended to remove it
in order to prevent damage.
a. From the front panel side of this set, push in the sections
marked with arrows and pull out the CD tray toward the
front.
b. Remove the CD tray panel by pushing both of its extremi-
ties upward in the direction of the arrows.
c. Push the CD tray deep into the set.
(1) Disconnect the cord wires from the CD board CN703
.
CN203
and
(2) From the rear of the set, remove two screws E, two screws
F and four screws G on the front panel left and right side.
(3) Handle the CD changer unit rear, take out the unit.
CD tray panel
E
Antenna
terminal
F
Fig.8
Fig.6
CD tray panel
Fig.7
G
Fig.9
(No.MB196)1-9
3.1.6 Removing the front panel assembly
(See Fig.10 to 11)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
(1) Disconnect the parallel wire and the cord wire from the con-
nectors CN701
(2) Remove one screws H retaining the front panel assembly
onto the bottom of the body.
(3) Remove two screws I on the left and right side of the set re-
taining the panel front from the bottom and then remove
then GND lug b that comes from the amp and supply
board.
(4) Disengage the claws c on both sides of the front panel as-
sembly and then remove the assembly.
, CN101 on the power amp. PCB.
H
Fig.10
a
Fig.11
GND lugGND lug
b
Claw
c
1-10 (No.MB196)
3.2 Disassembly of units and assembly inside this set
3.2.1 Removing the Main board
(See Fig.12 to 13)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
(1) Disconnect the wires from CN603A
on the Main board, which is located on the back side of the
CD changer unit.
(2) The four screws J that retain the CD board should be re-
moved.
(3) Remove the CD board by pulling it toward the side where
the CN601
(4) Using solder, short the CD pickup to connect to short
round.
Caution:
After re-connecting the wires, be sure to remove the
shorting solder from the GND connection.
(5) Disconnect the card wire from the connector CN601
Main board and then remove the Main board.
is located.
, CN603B and CN604
on the
CD PCB
J
PAIN PCB
J
Fig.12
CN601
J
Short round
Fig.13
(No.MB196)1-11
3.2.2 Removing the CD changer mechanism assembly
(See Fig.14 to 15)
• Also remove the CD changer unit.
(1) Turn the CD changer mechanism cover base and remove
the screws d connecting the unit to the CD changer mechanism assembly.
(2) Removing four screws e retaining the CD mechanism hold-
er assembly.
Caution:
When replacing the CD changer mechanism assembly, be
sure not to mistake the positions of the silver color and copper
color spring.
CD changer
unit
CD changer
mechanism
assembly
d
Fig.14
e
( Green color )
e
( Green color )
Fig.15
e
( Red color )
e
( Red color )
1-12 (No.MB196)
3.2.3 Removing the CD pickup
r
(See Fig.16)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
• Also remove the CD changer mechanism.
(1) Widen the section f.
(2) While keeping the section f wide open, push the section g
in the direction of the arrow to remove the shaft, and then
remove the CD pickup.
CD pickup
f
3.2.4 Replacing the loading motor and rotor belt of the CD changer
(See Fig .17)
• Prior to performing the following procedures, remove the top
cover.
• Also open the CD changer tray.
(1) Remove the two screws L retaining the CD changer tray
loading motor.
(2) Remove the two screws M retaining the gear plate and take
it out, after remove the rotor belt from the pulley.
g
Shaft
Fig.16
M
L
3.2.5 Replacing the CD turn table and removing the motor
(See Fig.18 )
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
(1) Remove the one screws retaining the CD (Turn table).
(2) Remove the two screws retaining the stopper brackets on
both sides of the CD changer unit.
(3) Remove the stopper brackets from both sides of the CD
changer unit.
(4) Pull out the CD tray from the CD changer unit, all the way
and lift the tray to remove.
(5) Remove the gear and after push out the tray motor locker
and pull out the tray motor from the CD tray.
Fig.17
Turn table motor
Motor locker
Obligue gea
Fig.18
(No.MB196)1-13
3.2.6 Removing the cassette deck mechanism
(See Fig.19)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
• Also remove the front panel assembly.
(1) Remove six screws Z retaining the cassette deck mecha-
nism.
3.2.7 Removing the Key open board & the Key rec board
(See Fig.20)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
• Also remove the front panel assembly.
(1) Remove two screws P that retains the Key open board.
(2) Remove three screws L that retains the Key REC board.
Key open
board
P
Front panel
assembly
Z
Z
Fig.19
Front panel
assembly
Front panel
assembly
L
3.2.8 Removing the Display board
(See Fig.21)
• Also remove the CD changer unit.
• Also remove the front panel assembly.
(1) Remove six screws Q that retain the Display board from the
back of the front panel unit.
Key REC
board
Fig.20
Display
PCB
Q
Fig.21
Q
1-14 (No.MB196)
3.2.9 Removing the Switch board and sound mode and CD function switch board
y
(See Fig.20 to 23)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
• Also remove the front panel assembly.
(1) Pull out the volume control knob from the front of the front
panel assembly.(Fig.22)
(2) Remove six screws Q retaining the front panel assembly.
(3) Remove the Control/FL board.
(4) Remove eleven screws retaining the Switch (key 1)
board.(Fig.20)
(5) Remove two screws S retaining the sound mode and CD
function (key 2) switch board.(Fig.21)
Volume knob
Front panel assembl
Fig.22
Front panel
assembly
Volume
shaft
Fig.23
(No.MB196)1-15
3.2.10 Removing the cassette deck main motor, and replacing the main belts
r
(See Fig.19, 24 and 25)
• Prior to performing the following procedures, remove the top
cover and both sides board.
• Also remove the CD changer unit.
• Also remove the front panel assembly.
(1) Remove six screws Z retaining the cassette deck mecha-
nism. (Fig.19)
(2) Remove the cassette deck mechanism.
(3) Remove two screws t retaining the main motor from the
front side of the cassette deck.
Caution:
After attaching the main motor, check the orientation of
the motor and the polarity of the wires.
(4) From the backside of the cassette deck, remove the main
motor and two main belts.
Caution:
The lengths of the cassette A(playback only) and cassette B(record/play) main belts are different. When attaching the main belts, use the longer belt for cassette A.
Cassette deck mechanism
(Back side)
Cassette deck mechanism
(Front side)
t
Fig.24
Cassette deck main moto
3.2.11 Removing the leaf switches of the cassette deck mechanism
(See Fig. 19 and 26)
• Prior to performing the following procedures, remove the top
cover and both sides board.
• Also remove the CD changer unit.
• Also remove the front panel assembly.
(1) Remove the six screws Z that retain the cassette deck
mechanism. (Fig.19)
(2) Remove the cassette deck mechanism.
(3) Turn the cassette deck mechanism upside down.
(4) Remove the solder from around the leaf switches.
(5) Pull out the leaf switches from the front side of the cassette
deck mechanism.
Main belt
(For B cassette)
Fig.25
Solder side of leaf switch
Cassette deck mechanism
Fig.26
Main belt
(For A cassette)
(Back side)
1-16 (No.MB196)
3.2.12 Removing the cassette deck heads
(See Fig. 19 and 27)
• Prior to performing the following procedures, remove the top
cover and both sides board.
• Also remove the CD changer unit.
• Also remove the front panel assembly.
(1) Remove six screws Z that retain the cassette deck mecha-
nism. (Fig.19)
(2) Remove the cassette deck mechanism and place it so that
the front side faces up.
(3) Remove the solder from the bottom side of the head termi-
nal and disconnect the wire.
(4) Remove screws U that retains the head.
(5) Remove screws V that retains the head.
(6) Hold the head and slide it in the direction of the arrow to re-
move it.
3.2.13 Removing the 3-pin regulator and bridge diode
(See Fig. 28)
• Prior to performing the following procedures, remove the top
cover and both sides board.
Remove two screws A that connect the heat sink.
(1) Remove two screws A that connect the heat sink.
(2) Remove two screws W that connect the heat sink.
(3) Remove the solder fixing the the 3-pin terminal regulator
, Q608.
Q604
(4) Remove the solder fixing the 4-pin bridge diode (D614
D615).
PB Head
Cassette deck mechanism
(Front side)
V
U
VU
REC/PB Head
Fig.27
W
A
,
Fig.28
(No.MB196)1-17