JVC MX-KC2 User manual

SERVICE MANUAL
COPYRIGHT © 2005 Victor Company of Japan, Limited No.MB434
2005/10
COMPACT COMPONENT SYSTEM
MB434200510
MX-KC2
Lead free solder used in the board (material : Sn-Ag-Cu, melting point : 219 Centigrade)
TABLE OF CONTENTS
1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
CA-MXKC2 SP-MXKC2SP-MXKC2
Area suffix
UW ----------- Brazil,Mexico,Peru
UY ------------------------ Argentina

1-2 (No.MB434)
SPECIFICATION
Design and specifications are subject to change without notice.
Amplifier Output Power 50 W per channel, min. RMS, driven into 6 Ωat 1kHz, with no
more than 10% total harmonic distortion. (IEC 268-3)
Input Sensitivity/Impedance
(1 kHz)
AUX IN 400 mV/50 kΩ
Speaker terminals 6 Ω- 16 Ω
Phones 32 Ω- 1 kΩ
15 mW/ch output into 32 Ω
Cassette Deck Section Frequency Response Type l (NORMAL) 63 Hz - 12 500 Hz
Wow And Flutter 0.15% (WRMS)
CD Player CD Capacity 3 CDs
Dynamic Range 83 dB
Signal-To-Noise Ratio 85 dB
Wow And Flutter Unmeasurable
Tuner FM Tuner : Tuning Range 87.5 MHz - 108.0 MHz(at AM10 kHz channel space)
87.50 MHz - 108.00 MHz(at AM9 kHz channel space)
AM Tuner : Tuning Range 530 kHz - 1710 kHz (at AM10 kHzchannel space)
531 kHz - 1710 kHz (at AM9 kHzchannel space)
Unit Dimensions 270 mm ×308 mm ×410 mm (W/H/D)
Mass Approx. 6.5 kg
Speaker Specifications
(each unit)
Type 2-way bass-reflex type
Speaker Unit Woofer : 13 cm cone ×1
Tweeter : 5 cm cone ×1
Power Handling Capacity 50 W
Impedance 6 Ω
Frequency Range 45 Hz - 22 000 Hz
Sound pressure level 87 dB/W·m
Dimensions 205 mm ×308 mm ×209 mm (W/H/D)
Mass Approx. 2.9 kg
Power Specifications Power Requirements AC 110 V - 127 V/220 V - 240 V , adjustable with voltage se-
lector, 50 Hz/60 Hz
Power Consumption 110 W (power on mode)
13 W (in Standby mode)
1.2 W (in Eco mode)

(No.MB434)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, 1,000Ωper volt or more sensitivity
in the following manner. Connect a 1,500Ω10W 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.).
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

1-4 (No.MB434)
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.

(No.MB434)1-5
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.
Fig.1
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 Afrom the heat sink between the
power IC.
(2) Remove the solder fixing the power IC.
Fig.2
3.1.3 Replacing the heat sink cover
(See Fig.3)
(1) Remove four screws Bfrom the rear panel.
(2) Pull the heat sink cover outward.
Fig.3
Fuse (F901)
1.6AL 250V
WA
B

1-6 (No.MB434)
3.1.4 Removing the top cover right cabinet and left cabinet
(See Fig.4 and 5)
(1) Remove three screws Cthat retain the top cover from the
panel rear of the body.
(2) Remove six screws Dthat retain the left cabinet from the
body.
(3) Remove six screws cthat retain the right cabinet from the
body.
Fig.4
Fig.5
top cover
right cabinet
left cabinet
C
CD
Right Front panel assembly
C
C
Left Front panel assembly
D
C

(No.MB434)1-7
3.1.5 Removing the CD changer unit
(See Fig.6 to 8)
• Prior to performing the following procedures, remove the top
cover.
Caution:
Although the CD mechanism unit can be removed without re-
moving the CD tray panel, it is still recommended to remove it
in order to prevent damage.
• From the front panel side of this set, push in the sections
marked with arrows and pull out the CD tray toward the front.
• Remove the CD tray panel by pushing both of its extremities
upward in the direction of the arrows.
• Push the CD tray deep into the set.
(1) Disconnect the cord wires from the CD board CN703 and
CN203.
(2) From the rear of the set, remove two screws E, and four
screws Gon the front panel left and right side.
(3) Handle the CD changer unit rear, take out the unit. Fig.6
Fig.7
Fig.8
UP
UP
CD tray panel
E
G

1-8 (No.MB434)
3.1.6 Removing the front panel assembly
(See Fig.9 to 10)
• 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, CN101 on the power amp. board.
(2) Remove one screws Hretaining the front panel assembly
onto the bottom of the body.
(3) Remove two screws Ion the front cabinet and bottom cab-
inet and then remove then GND lug bthat comes from the
power amp and supply board.
(4) Disengage the claws con both sides of the front panel as-
sembly and then remove the assembly.
Fig.9
Fig.10
IH
Claw c
GND lug b
GND lug a

(No.MB434)1-9
3.2 Disassembly of units and assembly inside this set
3.2.1 Removing the Main board
(See Fig.11 to 12)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
(1) Disconnect the wires from CN603A, CN603B and CN604
on the Main board, which is located on the back side of the
CD changer unit.
(2) The four screws Jthat retain the CD board should be re-
moved.
(3) Remove the CD board by pulling it toward the side where
the CN601 is located.
(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 on the
Main board and then remove the Main board.
Fig.11
Fig.12
Main board
J
J
J
CD board
Short round
CN601

1-10 (No.MB434)
3.2.2 Removing the CD changer mechanism assembly
(See Fig.13 to 14)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
(1) Turn the CD changer mechanism cover base and remove
the screws dconnecting the unit to the CD changer mech-
anism assembly.
(2) Removing four screws eretaining 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.
Fig.13
Fig.14
d
CD changer unit
assembly
e ( Green color )
e ( Red color )
e ( Green color )
e ( Red color )
CD changer
mechanism

(No.MB434)1-11
3.2.3 Removing the CD pickup
(See Fig.15)
• 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 fwide open, push the section g
in the direction of the arrow to remove the shaft, and then
remove the CD pickup.
Fig.15
3.2.4 Replacing the loading motor and rotor belt of the CD changer
(See Fig .16)
• Prior to performing the following procedures, remove the top
cover.
• Also open the CD changer tray.
(1) Remove the two screws Lretaining the CD changer tray
loading motor.
(2) Remove the two screws Mretaining the gear plate and take
it out, after remove the rotor belt from the pulley.
Fig.16
3.2.5 Replacing the CD turn table and removing the motor
(See Fig. 17)
• Prior to performing the following procedures, remove the top
cover.
• Also remove the CD changer unit.
(1) Remove the one screw 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
g
f
CD pickup
Shaft
M
L
Motor locker
Turn table motor
Obligue gea
r

1-12 (No.MB434)
3.2.6 Removing the cassette deck mechanism
(See Fig.18)
• 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 retaining the cassette deck mecha-
nism.
Fig.18
3.2.7 Removing the key open board & the key REC board
(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 25 screws Pthat retains the key open board.
Fig.19
3.2.8 Removing the display 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 25 screws Qthat retain the front board from the
back of the front panel unit.
Fig.20
Front panelassembly
Z
Z
Front panel
assembly
Front board
P
Q
Display board

(No.MB434)1-13
3.2.9 Removing the Switch board and sound mode and CD function switch board
(See Fig.19 to 22)
• 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.21)
(2) Remove six screws Qretaining the front panel assembly.
(3) Remove the Control/FL board.
(4) Remove eleven screws Rretaining the Switch (key 1)
board.(Fig.19)
(5) Remove two screws Sretaining the sound mode and CD
function (key 2) switch board.(Fig.20)
Fig.21
Fig.22
Volume knob
Front panel assembly
Front panel assembly Volum shaft

1-14 (No.MB434)
3.2.10 Removing the cassette deck main motor, and replacing the main belts
(See Fig.18, 23 and 24)
• 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 Zretaining the cassette deck mecha-
nism. (Fig.18)
(2) Remove the cassette deck mechanism.
(3) Remove two screws tretaining 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.
Fig.23
Fig.24
3.2.11 Removing the leaf switches of the cassette deck mechanism
(See Fig. 18 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 the six screws Zthat retain the cassette deck
mechanism. (Fig.18)
(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.
Fig.24
t
Cassette deck mechanism (Front side)
Cassette deck mechanism
(Back side)
Cassette deck main moto
r
Main belt
(For A cassette)
Main belt
(For B cassette)
Cassette deck mechanism
(Back side)
Solder side of leaf switch

(No.MB434)1-15
3.2.12 Removing the cassette deck heads
(See Fig. 18 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 six screws Zthat retain the cassette deck mecha-
nism. (Fig.18)
(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 Uthat retains the head.
(5) Remove screws Vthat retains the head.
(6) Hold the head and slide it in the direction of the arrow to re-
move it.
Fig.26
3.2.13 Removing the 3-pin regulator and bridge diode
(See Q604, Q608, D614, D615 and Fig.27)
• Prior to performing the following procedures, remove the top
cover and both sides board.
(1) Remove two screws Athat connect the heat sink.
(2) Remove two screws Wthat connect the heat sink.
(3) Remove the solder fixing the 3-pin terminal regulator Q604,
Q608.
(4) Remove the solder fixing the 4-pin bridge diode (D614,
D615).
Fig.27
Cassette dec k mechanism (Front side)
V UVU
PB Head REC/PB Head
A
W

1-16 (No.MB434)
3.2.14 Removing the power amp and Supply board and the Power trans board
(See Fig. 2, 28 to 30)
• Prior to performing the following procedures, remove the top
cover and CD changer unit.
(1) Remove four screws Bfrom the rear panel. (Fig.3)
(2) Pull the heat sink cover outward.
(3) Remove four screws AA from the rear panel between the
heat sink holder.
(4) Remove two screws YY that retains the rear panel, and
then remove the rear panel.
(5) Disconnect the parallel wires from the connectors FW951
on the Power trans board.
(6) Remove screws Zthat retain the power amp and Supply
board and then remove the assembly.
(7) Remove the clamp of AC power cord from the chassis.
(8) Remove four screws that retain the Power trans board and
then remove the assembly. Fig.28
Fig.29
Fig.30
Fuse (F901)
1.6AL 250V
YY
Clamp
Power amp and supply board
Rear panel
Chassis
Z

(No.MB434)1-17
SECTION 4
ADJUSTMENT
This service manual does not describe ADJUSTMENT.
SECTION 5
TROUBLESHOOTING
This service manual does not describe TROUBLESHOOTING.

(No.MB434)
AV & MULTIMEDIA COMPANY AUDIO/VIDEO SYSTEMS CATEGORY 10-1,1chome,Ohwatari-machi,Maebashi-city,371-8543,Japan
Victor Company of Japan, Limited
VPT
Printed in Japan

SCHEMATIC DIAGRAMS
MX-KC2
Contents
Block diagram
Standard schematic diagrams
Printed circuit boards
2-1
2-2
2-8 to 13
CD-ROM No.SML200510
COMPACT COMPONENT SYSTEM
No.MB434SCH
2005/10
COPYRIGHT 2005 Victor Company of Japan, Limited.
Lead free solder used in the board (material : Sn-Ag-Cu, melting point : 219 Centigrade)
CA-MXKC2 SP-MXKC2SP-MXKC2
Area suffix
UW ----------- Brazil,Mexico,Peru
UY ------------------------ Argentina

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.