JVC UX-G50J User manual

SERVICE MANUAL
COPYRIGHT © 2006 Victor Company of Japan, Limited No.MB509
2006/3
MICRO COMPONENT SYSTEM
MB50920063
UX-G50J,UX-G50C
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
CA-UXG50 SP-UXG50SP-UXG50

1-2 (No.MB509)
SPECIFICATION
Design and specification are subject to change without notice.
Amplifier section Output Power 120 W per channel, min. RMS, driven into 6 Ωat 1 kHz with no more than 10% total har-
monic distortion.
Speakers Impedance 6 Ω- 16 Ω
Audio Input AUX Input sensitivity/Impedance:
LEVEL1:150 mV/47 kΩ
LEVEL2:500 mV/47 kΩ
USB USB Ver. 1.1
Tuner section FM tuning range 87.5 MHz - 108.0 MHz
AM tuning range 530 kHz - 1 710 kHz
CD player section Dynamic range 85 dB
Signal-to-noise ratio 85 dB
Wow and flutter Immeasurable
General Power requirement AC 120 V , 60 Hz
Power consumption 155 W (at operation)
20 W (at standby)
0.8 W (at on standby and Display off)
Dimensions (approx.) 175 mm ×246 mm ×415 mm (6-15/16" ×9-11/16" ×16-3/8") (W/H/D)
Mass (approx.) 7.4 kg (16.4 lbs)
Speakers Type 2-way Bass reflex
Speaker units Woofer 12 cm (4") cone ×1
Tweeter 4 cm (1-5/8") cone ×1
Impedance 6 Ω
Dimensions (approx.) 145 mm ×246 mm ×212 mm (5-3/4" ×9-11/16" ×8-3/8") (W/H/D)
Mass (approx.) 2.2 kg (4.9 lbs) each

(No.MB509)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.MB509)
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
Pickup board
short rand

(No.MB509)1-5
1.8 Importance administering point on the safety
Graphic symbol mark
(This symbol means fast blow type fuse.)
FOR CONTINUED PROTECTION AGAINST RISK
OF FIRE, REPLACE ONLY WITH SAME TYPE
AND RATING OF FUSES ;
should be read as follows ;
F901 : 3.15A 250V F901 : 3.15A 250V
Full Fuse Replacement Marking
FUSE CAUTION
Le symbole graphique (Ce symbole signifie
fusible de type a fusion rapide.)
POUR UNE PROTECTION CONTINUE CONTRE
DES RISQUES D'INCENDIE, REMPLACER
SEULEMENT PAR UN FUSIBLE DU MEME TYPE ;
Marquage Pour Le Remplacement
Complet De Fusible
PRECAUTIONS SUR LES FUSIBLES
doit etre interprete comme suit ;
^

1-6 (No.MB509)
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.

(No.MB509)1-7
SECTION 3
DISASSEMBLY
3.1 Main body
3.1.1 Removing the metal plate
(See Fig.1 and 2)
(1) Remove the six screws Aattaching the metal plate from
back side of main body. (See Fig.1)
(2) Remove the four screws Battaching the metal plate from
both side of main body. (See Fig.2)
3.1.2 Removing the top cover
(See Fig.1 and 3)
(1) Remove the one screw Cattaching the top cover from back
side of main body. (See Fig.1)
(2) Remove the two screws Dattaching the top cover from
both side of main body. (See Fig.3)
(3) Disengage hook aon both side of the front panel. (See
Fig.3)
Fig.1
Fig.2
Fig.3
A
C
A
B
B
D
P
a
c
Earth wire

1-8 (No.MB509)
3.1.3 Removing the main board
(See Fig.4)
(1) Remove the two screws Eattaching the main board. (See
Fig.4)
(2) Disconnect the card wires connected to connector CN402,
CN411, CN412, CN661 and CN681 of main board.
(3) Disconnect the connector wire connected to connector
CN671 of main board.
(4) Disconnect the board connector connected connector
CN501 and CN601 between amp board and main board.
Fig.4
3.1.4 Removing the power board
(See Fig.5 and 6)
(1) Remove the two screws Fattaching the power board. (See
Fig.5)
(2) Disconnect the power cord connected connector CN901
and power transformer connector wire connected connec-
tor CN902 of power board. (See Fig.5)
(3) Disconnect the connector wire connected connector
CN102 of amp board.(See Fig.6)
Fig.5
Fig.6
EE
CN402 CN671 CN681
CN411
CN412 CN661
CN601 CN501
CN901
CN902
F
CN102CN181

(No.MB509)1-9
3.1.5 Removing the rear plate
(See Fig.7 and 8)
(1) Remove the four screws Gattaching the trans cover. (See
Fig.7)
(2) Remove the one screw Hattaching the rear plate. (See
Fig.7)
(3) Remove the two screws Jattaching the speaker terminal.
(See Fig.7)
(4) Disengage hook bon both side of main chassis. (See
Fig.8)
(5) Disconnect the connector wire from fan connected connec-
tor CN105 of amp board.(See Fig.8)
3.1.6 Removing the fan
(See Fig.7)
(1) Remove the four screws Kattaching the fan.
3.1.7 Removing the tuner pack
(See Fig.7)
(1) Remove the two screws Lattaching the tuner pack.
3.1.8 Removing the amp board
(See Fig.6, 8 and 9)
(1) Disconnect the connector wire connected to connector
CN181, CN204, CN205 and CN206 of the amp board. (See
Fig.6 and 8)
(2) Remove the seven screws Mattaching the amp board.
(See Fig.9)
Fig.7
Fig.8
Fig.9
G
J
L
G
H
K
K
bb
CN105
CN204 CN206
CN205
M
M

1-10 (No.MB509)
3.1.9 Removing the front panel
(See Fig.3 & 10)
(1) Remove the two screws Nattaching the front panel assem-
bly. (See Fig.10)
(2) Remove the two screws Pattaching the front panel assem-
bly. (See Fig.3)
(3) Disconnect the earth wires from main chassis. (See Fig.3)
(4) Disengage hook con the both side of main chassis. (See
Fig.3)
Fig.10
3.1.10 Removing the front board
(See Fig.11)
(1) Disconnect the connector wire connected connector
CN301 of front board.
(2) Remove the four screws Qattaching the front board.
3.1.11 Removing the key board
(See Fig.11)
(1) Disconnect the volume knob.
(2) Remove the eleven screws Rattaching the key board.
3.1.12 Removing the USB board
(See Fig.11)
(1) Remove the four screws Sattaching the USB board.
Fig.11
3.1.13 Removing the power transformer
(See Fig.12)
(1) Remove the four screws Tattaching the power transform-
er.
Fig.12
NN
Q
R
R
S
Q
CN301
T
T

(No.MB509)1-11
3.1.14 Removing the CD mecha cover
(See Fig.13 to 15)
(1) Remove the four screws Uattaching the CD mecha cover.
(See Fig.13)
(2) Remove the two screws Vattaching the CD mecha holder
F. (See Fig.14)
(3) Remove the two screws Wattaching the CD mecha holder
R. (See Fig 15)
Fig.13
Fig.14
Fig.15
U
V
W

1-12 (No.MB509)
3.1.15 Removing the CD board
(See Fig.16 to 18)
(1) Disconnect the card wire from connector CN871 of CD
board. (See Fig.16)
(2) Disconnect the connector wire connected to connector
CN872 and CN873 of CD board. (See Fig.16)
(3) Disconnect the connector wire from CN702 of CD board
connected to motor board connector. (See Fig.17)
(4) Remove the four screws Xattaching the CD board. (See
Fig.16)
(5) Solder the short land section of the CD pickup. (See
Fig.18)
Caution:
• Solder the short land section of the CD pickup before
disconnecting the card wire from the connector on the
CD pickup. If the card wire id disconnected without at-
taching the solders, the pick up may be destroyed by
static electricity.
• When attaching the CD pickup, be sure to remove sol-
ders from the short land section after connecting the
card wire to the connector on the CD pickup.
(6) Disconnect the card wire from connector of CD pickup.
(See Fig.18) Fig.16
Fig.17
Fig.18
X
CN871
CN872CN873
CN702
CN702
Pickup board
short rand

(No.MB509)1-13
3.1.16 Removing the CD mechanism
(See Fig.19)
(1) Remove the three screws Yattaching the CD mechanism.
Fig.19
YY
Y

1-14 (No.MB509)
SECTION 4
ADJUSTMENT
This service manual does not describe ADJUSTMENT.

(No.MB509)1-15
SECTION 5
TROUBLESHOOTING
This service manual does not describe TROUBLESHOOTING.

(No.MB509)
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
UX-G50J,UX-G50C
Contents
Block diagrams
Standard schematic diagrams
Printed circuit boards
2-1
2-3
2-11 to 20
CD-ROM No.SML200603
MICRO COMPONENT SYSTEM
No.MB509SCH
2006/3
COPYRIGHT 2006 Victor Company of Japan, Limited.
Lead free solder used in the board (material : Sn-Ag-Cu, melting point : 219 Centigrade)
CA-UXG50 SP-UXG50SP-UXG50

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.

< MEMO >

2-1
Block diagram
PICKUP
ASS'Y
LOADER
ASS'Y
Motor
driver
ASP 16M
SDRAM
CD/MP3
DECODER
VFD
D
V
d
CD board
VOLTAGE SUPPLY
SYSTEM
MICON
AC RELAY
Main
trans
Sub trans
<=1W
Fuse
AC IN
VREF
SVCC
A,B,C,D,E,F
GND
LD
VR
PD
T+,T-
F+,F-
SP+/-, SL+/-
IN-SW
MO+/-, RL+/-
5V
SENSE CATHODE
SW1-2 16.93MHz
SPDRV
TRVDRV
FG
FODRV
DRVMUTE
SPMUTE
VHALF
8V
3.3V
DB0-7
ADD0-10
BAO RAS CAS DRW
LDQM CKE
XSCLK UDQM
FAOUTL
FAOUTR
DISPLAY O/P