Jvc XLZ 574 BK Service Manual

Page 1

JVB
SERVICE MANUAL

XL-2574BK

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Con tents
Safety Precautions ........................ 1-2 Maintenance of Laser Pickup ............. 1-27
Important for Laser Products .............. 1-3 Replacement of Laser Pickup ............. 1-27
Instruction Book .......................... 1 4 Troubleshooting ......................... 1 -28
Description of Mcy'or 1.51s ................ 1-12 Block Diagram ......................... 1-33
Internal Block Diagram of Other ICs . . . . 1-20 Schematic Diagram ................. Insertion
Internal Connection of FL Display Tube . . 1-21 Printed Circuit Boards ............... Insertion
Disassembly Procedures .................. 1-22 Parts List ................................ 2-1
Flow of Functional Operation
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Aumo DIVISION ,YAMATO PLANT,1W,SH|MOTSURUMA.YAMATO-SHI,KANAGAWA-KEN,242.}APAN " """""
a Primed in Japan NO. 20481
(No. 20481) 9406(5) Jun. 1994

Page 2

XL-2574BK

--Safety Precautions

1. The 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 (A) on the Parts
List in the Service Manual. The use of a substitute repalcement 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 re-assembling.

5. Leakage currnet 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,
contorl 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.

0 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.).

0 Alternate check method
Plug the AC line cord directly into the AC outlet. Use an AC voltmeter having, 1,000
ohms per volt or more sensitivity in the following manner. Connect a 1,5000. 10 W
resistor paralleled by a 0.15 ,uF AC-type capacitor between an exposed metal part and a
known good earth ground.

Measure the AC voltage across the resistor a {iiii'igfiggim
With the AC voltmeter. ohms/volts, g
Move the resistor connection to each exposed 9 °_ ° "0 59"""'>-
metal part, particularly any exposed metal part

having a return path to the chassis, and 0,15,;F Ac TYPE

meausre the AC voltage across the resistor. -|}- .
Now, reverse the plug in the AC outlet and 1 Piafeh
repeat each measurement. Any voltage vvv $232), e330,
measured must not exceed 0.75 VAC (r.m.s.). 150°01°W metal part.

This corresponds to 0.5 mA AC (r.m.s.). Good earth ground

Important for Laser Products
CLASS 1 LASER PRODUCT

2. DANGER: Invisible laser radiation when open and

interlock failed or defeated. Avoid direct exposure to
beam.

3. CAUTION : There are no serviceable parts inside the

Laser Unit. Do not disassemble the Laser Unit. Replace
the complete Laser Unit if it malfunctions.

4. CAUTION Z The compact disc player uses 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.

VARNING : Osynlig laserstrllning nar denna del ar
Oppnad och sparren Ir urkopplad. Betrakta
ej strblen.

VARO : Avattaessa ja suojalukitus ohitettaessa olet
alttiina nlkymlttbmllle laserslteilylle. All

katso slteeseen.

5.

6.

XL-ZS74BK

CAUTION : If safety switches malfunction, the

laser is able to function.

CAUTION : Use of controls. adjustments or
performance of procedures other than those

specified herein may result in hazardous radiation

exposure.

ADVARSEL: Usynlig Iaserstrlling ved abning. nlr

sikkerhedsafbrydere er ude af funktion. Undga
udsaittelse for straling.

ADVARSEL: Usynlig laserstrlling ved apning, nlr

sikkerhetsbryteren or avslott. unngl utsettelse for
straling.

- 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.

1-2 (No. 20481)

REPRODUCTION AND POSITION OF LABELS

WARNING LABEL
(Except for the U. S. A.)

DANGER: Irwislble laser

VARNING: Osynllng laser

radiatlon when open and strlllng nlr demu del
merlock failed or defeated. I Owned och splrren Ir
VOID DIRECT EXPOWIE urkoppled. Sanka e]
o BEAM. (e) Eulen. (s)

ADVARSEL: Usynllngluer-
strafing vld lbnlng. nlr
slkkerhedslfbrydere er ode
at funktlon. Undgludsm-
telse for strlllng. (d)

VARO: mm]: :00
)alukltus ohltettaesu olet
alttllru nlkymmornllle
lmdiylle. AII lam

Enema. (1)

CLASS I

LASER PRODUCT

CLASSIFICATION LABEL
(Except for the U. S. A. and Canada)

(No. 20481) 1-3