Jvc UX-G28 Service Manual
SERVICE MANUAL
MICRO COMPONENT SYSTEM
MB63420079SERVICE MANUAL
UX-G28B, UX-G28E, UX-G28EN,
UX-G28EV
SERVICE POLICY
No service part is available for this model.
Exchange only.
SP-UXG28SP-UXG28 CA-UXG28
EV only
COPYRIGHT © 2007 Victor Company of Japan, Limited
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
COPYRIGHT © 2007 Victor Company of Japan, Limited
No.MB634
2007/9
SPECIFICATION
Amplifier section Output Power 8 W per channel min. RMS driven into 4 Ω at 1 kHz with no more than 10% total harmonic
distortion. (IEC268-3)
Speakers/Impedance 4 Ω - 8 Ω
Terminals AUX IN Input sensitivity/Impedance (250mV/50kΩ):USB Ver.2.0 (Full Speed)
Compatible device Mass Storage Class
Compatible File System FAT16, FAT32
Bus Power supply Max 5V/500mA
Tuner section FM tuning range 87.50 MHz - 108.00 MHz
AM (MW) tuning range 522 kHz - 1 629 kHz
CD player section Dynamic range 70 dB
Signal-to-noise ratio 70 dB
General Power requirement AC 230 V , 50 Hz
Power consumption 32 W (at operation)
0.7 W (on standby)
Dimensions (approx.) 144 mm × 212 mm × 254 mm (W/H/D)
Mass (approx.) 2.5 kg
Speakers Type 1-way Bass reflex
Speaker units 10 cm cone × 1
Impedance 4 Ω
Dimensions (approx.) 136 mm × 212 mm × 178 mm (W/H/D)
Mass (approx.) 1.3 kg each
Design and specifications are subject to change without notice.
1-2 (No.MB634)
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.MB634)1-3
1.5 Safety Precautions (U.K only)
(1) This design of this product contains special hardware and many circuits and components specially for safety purposes. For con-
tinued 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.
(2) Any unauthorised design alterations or additions will void the manufacturer's guarantee; furthermore the manufacturer cannot
accept responsibility for personal injury or property damage resulting therefrom.
(3) Essential safety critical components are identified by ( ) on the Parts List and by shading on the schematics, and must never
be replaced by parts other than those listed in the manual. Please note however that many electrical and mechanical parts in
the product have special safety related characteristics. These characteristics are often not evident from visual inspection. Parts
other than specified by the manufacturer may not have the same safety characteristics as the recommended replacement parts
shown in the Parts List of the Service Manual and 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 re-assembling.
1.5.1 Warning
(1) Service should be performed by qualified personnel only.
(2) This equipment has been designed and manufactured to meet international safety standards.
(3) It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
(4) Repairs must be made in accordance with the relevant safety standards.
(5) It is essential that safety critical components are replaced by approved parts.
(6) If mains voltage selector is provided, check setting for local voltage.
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 (No.MB634)
1.6 Important for laser products
1.CLASS 1 LASER PRODUCT
2.CAUTION :
(For U.S.A.) Visible and/or invisible class II laser radiation
when open. Do not stare into beam.
(Others) Visible and/or invisible class 1M laser radiation
when open. Do not view directly with optical instruments.
3.CAUTION : Visible and/or invisible laser radiation when
open and inter lock failed or defeated. Avoid direct
exposure to beam.
4.CAUTION : This laser product uses visible and/or 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 and PRINT
WARNING LABEL and PRINT
(No.MB634)1-5
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.
1-6 (No.MB634)
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