Jvc RC 450 LBK Service Manual

Page 1

Fix-4508K
RX-450LB

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Safety Precautions .............................. 1-2 Connection Diagram ........
Instruction Book Schelatic Diagrams
OCR may --------------------------------- 13 (URX'4SOBK Tuner Section ------------- av Insertion
Rennval Procedures ----------------------------- 1-4 (2)RX-450LBK Tuner Section --------------- Insertion
FM/HH/Lw Tuner AIignIent Procedures ----------- 15 (3)Logic Section ------------------------ Insertion
Pouer Alplifier IdIing Current Adjustment 1-6 (Power Alplifier Section --------------- Insertion
Function of ICs on the Pre~AmpliEier PCB 1-6 Parts List ---------------- Separate-value Insertion
Internal Block Diagrals of Major LSI [Cs --------- I~7
No. 297(

Feb 198

Page 2

Fix-4508K
RX -4 SOLBK

Safety Precautions

1. The design of this product contains special hardware and

many circuits and components specially for safety pur-
poses.
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
performed by qualified personnel only.

2. Alterations of the design or circuitry 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
injury or property damage res "

_ .g therefromu

3. Many electrical and mechanical parts in the product
have special safety-related characteristics. These charac-
teristics are often not evident from visual inspection nor
can the protection afforded by them necessarily be ob-
tained 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 the Service Manual. Electrical components
having such features are identified by shading on the
schematics and by l 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 recom-
mended replacement part shown in the Parts List of
the,$ervice 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 sepa-
rated from live parts, high temperature parts, moving
pans 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
the they have been returned to normal, after reassembl-

mg.

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 omlet.
Using a Leakage Current Tester", measure the
leakage current from each exposed metal part of the
cabinet, particularly any exposed metal pan having a
return path to the chassis, to a known good earth
ground. Any leakage current must not exceed 0.5 mA
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 1,500 9
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 with the
AC voltmeter.
Move the resistor connection to each exposed metal
part, particularly any exposed metal pan 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 0.75 V AClr.m.s.).
This corresponds to 0.5 mA AClrms).

AC VOLTMETER
@ (Having 1000 ohms/volt.
or more sensitivrty.)
a c

0.15;} AC YVPE

Place this probe

r
l
l
l

I Before inserting the paper plug, please check that the voltage selector's setting corresponds with
Ithe line voltage in your area. If it. doesn't. be sure to reset. the voltage selector before operating

this equipment.

The voltage selector may be located on the rear or button of the unit. or underneath the platter.

:CAUTIUN : Before setting the voltage selector to the proper voltage. disconnect the power plug.

1J7 1M.» 7Q7fll

4% on each exposed
isoon row metal part.
Good earth ground
CHECK THE VOLTAGE SELECTOR'S SETTING - -

(Except for U.S.A., Canada. Australia. U.K. and Continental Europe)

-_-._-_____J

) .