Jvc UXT 1 Service Manual

Page 1

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Jvc

:lfiOMPACT
DIGITAL AUDIO
White, Black 2 type
Area Suffix

B , ...................... UK

E . , Continental Europe

G . Germany

GI ....... ltay

North Europe
E Safety Precautions .Pagez @ Block Diagram ............................................... 49
E Safety Precaution about UX-T1 - 3 \El Wiring Connections -------------
B] Main Features ----------------------------- fij] Standard Schematic Diagrams -
E Specifications ----------------------------------------------------- 5 fl] Location of P.C. Board Pans~- - 63
E] lnstrucflons(Extract) ............................................ 5 [3| Elecmcal Parts List ............
E] Location of Main pans .......... . ............................. 26 @ Illustration of Packing and Pans Ust .................. 86
El Removal of Maln Pans ...................................... 28
{E Main Adjustment ................................................ 40
No. 1877-C
January 1995
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Page 2

Ux-nB/E/GIGIIEN/VX

1 Safety Precautions

1. The design 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 pans
must be identical to those used in the original circuits. Service 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 manufactures warranty and will further relieve the manufacture of responsibility for
personal injury or property damage resulting therefrom.

3. Many electrical and mechanical pans in the product 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 and( A )on the schematic
diagram and by ( A l 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 part 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.
alter reassembling.

5. Leakage current check (Electrical shock hazard testing)

After re - assembling 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 part of the cabinet. particulary any exposed metal part having a return path to the chassis. to a known good earth ground.
Any leakage current must not exposeed 0.5mA AC(r.m.s,)

m AC VO LTM ETE R
- Alternate check method (HaVing 1000 ohms/volt.
or more sensitivity.)

Plug the AC line cord directly into- the AC outlet. Use an AC

<2 0

-_l

0.15 F AC TYPE
following manner. Connect a 1.500 ohms 10W resistor paralleled by .

I

voltmeter having 1.000 ohms per volt or more sensitivity in the

a 0.15 u F AC type capacitor between an exposed metal part and Place this probe
W on each exposed
a known good earth ground. Measure the AC voltage across the 1500 n 10W metal pan.

resistor With the AC voltmeter, Move the resistor connection to each Good earth ground
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. Any voltage measured must not exceed 0.75V

ACtr.m.s.).This corresponds to 0,5mA AC(r,m,s.).

0 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 maintaintained.
3. Repairs must be made in accordance with the relevant safety standards.

4. it is essential that safety critical components are replaced by approved pans.

5. If mains voltage selector is provided. check setting for local voltage.

2 (No. 1877-C)

Page 55

I CD player Section

UX'T1B/E/G/GIIEN/VX

Item

Conditions

Adjustment & Confirmation Methods

Stand. values Adlust

Tracking offset
adjustment

Test disc
:CT81 000
Oscilloscope

®Connect an oscilloscope across the test points
TP503 (hot side)and TP501 ( Earth side).

® Play the test disc CTS1000.

@Shortclrcuit the TP504 to the TP501 while playing
, then the tracking error signal will be emitted for
about 3 seconds.

@Adiust the VR501 so that the waveform of the
tracking error signal on the oscilloscope becomes
symetrical to the DC zero level.

©Repeat the steps 2, 3. and 4 for the best result
since the tracking error signal appears on the
screen just for 3 sconds.

Tracking error signal

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Note : The oscilloscope shall be connected by DC
coupling.

Set the center VR501
of P - P to the
DC zero level.

Set the center of P-P to
the DC zero level.

I Arrangement of adiustlng positions: CD Amplifier P.C. board

(No, 1877-C) 47