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Safety Precautions
1. The design of this product contains special hardware.
Many circuits and compo nents 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. Service should be per
formed 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 manufacturer's warranty and will further relieve the
manufacturer of responsibi lity for personal injury or pro
perty damage resulting therefrom.
3. Many electrical and mechanical parts in the product have
special
safety - related characteristics. These characteri
stics 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. El ectrical components hav
ing such features are
identified by (Lt) on the schematics
and
parts list in 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 in 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/ or the like to be
separated
from live parts, high temperature part, mov
ing
parts and / or sharp edges for the prevention of elec
tric shock and fire hazard .
When service is required , the original lead routing and
dress
should be observed, and they should be confirm
ed
to be returned to normal , after re -assembling.
5. Leakage current check
(Safety for electrical shock hazard)
A
fter re -assembling the product , always perform an isola
tion check on the exposed metal parts of the Products
(antenna terminals , knobs , metal cabinet, screw heads,
earphone jack , control shafts, etc.) to be sure the pro
duct is safe to operate without danger of electrical shock.
2 (No. 1740)
Do not use a line isolation transformer du ring this check.
- Plug
the AC line cord directly into the AC outlet. Us
in g a "Leakage Current Tester", measure the leakage
current from each exposed metal part of the cabinet,
particularly any exposed metal part having a return
path to the chassis, to a known good earth ground
(water pipe, etc.). Any leakage current must not ex
ceed 0.5 mA AC (r.m.s.).
- 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 1500 {l
10 W resistor paralleled by a 0.15 /LF AC - type
capacitor between an exposed metal part and a known
good earth ground (water pipe , etc.)
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. Any
voltage measured must not exceed 0.75 V AC
(r.m.s.) .
This corresponds to 0.5 mA AC (r.m .s.).
AC VOLTMETER (HAVING 1000 ON , OR MORE SENSITIVITY I
0.1 5 /LF AC -TYPE
GOOD EARTH GROUND PLACE
THIS PROBE
ON EACH EXPOSED
METAL PART
