Jvc XLV 235 TN Service Manual

Page 1

SERVICE iMANUAL

XL-V231 B K
MODELNO. XL-V235TN

Contents

Safety Precautions ..................... Page 1 - 2
Important for Laser Products ............... Page 1 - 3
Instruction Book ........ . . Page 1 74
Description of Major LSls . , _ r ............ Page 1-11
Internal Circuit Block Diagram of the Other [(35 .. t .Page1-17
Internal Connectian for the FL Display Tube ..... Page 1-18
Disassembly Procedures ............. . , _ Page 1-19
Adjusting Procedures ................... Page 1-21
Maintenance of Laser Pickup ............... Page 1-22

@EIEE

DIGITAL AUDIO
Replacement of Laser Pickup ............... Page 1-22
Application Points for Grease ............... Page 1-23
Flow 01 Functional Operation Unit TOC Is Read . Page 1724
Troubleshooting ..................... Page 1~25
Connection Diagram .................... Insertion
Block Diagram Insertion
Schematic Diagram ....... . Insenion
Printed Circuit Board Ass'y . . t. . Insertion
Parts List ................ Separate-Volume Insertion
No. 20145

Dan 1989

Page 2

XL-V231BK/XL-V235TN

1

m

-Warning

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2
3.
4
5

Safety Precautions

. The design of this product contains special hardware and many circuits and Components specially for safety pdrposes.

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. Service should be per-
formed by qualified personnel only.

. 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 manufacturer of responsibility for personal iniury or property damage resulting therefrom.

. Many electrical and mechanical parts in the product have special safetvrelated 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 ol Service Manual. Electrical components having such features
are identified by (A) on the Schematic Diagram and Parts List in the Servrce 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.

. 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 Glrtittlt: 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 rte-assembling.

. Leakage current check (Electrical 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 lack, control shafts, etc.) to be sure the product
is safe to operate without danger of electrical shock.

00 not use a line isolation transformer during this check.

0 Plug the AC line card directly into the AC outlet. Using a "Leakage Current Tester, measure the leakage current
from each exposed metal part of the cabinet, particularly any exposed rnetal part having a return path to the
chassis, to a known good earth ground. Any leakage current must not exceed 0.5 mA AC (rams).

o Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having l,000 ohms per volt or more sensi-
tivity in the following manner. Connecta 1,500 52 10W resistor paralleled by a 0,15pF AC'ine capacitor be-
tween an exposed metal part and a known good earth ground.

Measure the AC voltage across the resistor With the 77: AC VOLTMETER
AC voltmeter ELJ lHavmg 1000 ohms/volt,

. . or more sensitivity.l
Move the resistor Connection to each exposed metal

part, particularly any exposed metal part having 3 i
return path to the chassis, and measure the AC voltr ° '5 "C "P
. , 7,..-
. th e t . .' h h
age across e r sis or Now, reverse t e plug in t e Place W5 prohe
AC outlet and repeat each measurement. Any voltage _ on each exposed
measured must not exceed 0.75 VAC (r m t ), This isoon row metal part

corresponds to 0.5 mA AC fr.m.s.l. Good earth ground

, This equipment has been designed and manufactured to meet international safety standards.

. It is the legal responsibility of the repairer to ensure that these safety standards are maintained,
Repairs must be made in accordance with the relevant safety standards.

. It is essential that safety critical components are replaced by approved parts.

. ll mains voltage selector is provided, check setting for local voltage,

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