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Safety Precaution
1. The design of this product contains special hardware,
QL-F300
No. 2650
many circuits and componets
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 per-
formed by qualified personnel only.
. 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 responsibility for personal in-
jury or property damage resulting therefrom.
. Many
electrical
and mechanical
parts in the product
have
special
safety-related
characteristics.
These
characteristics are often not evident from visual inspec-
tion 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 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 in Ser-
vice manual may create shock, fire, or other hazards.
. 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 parts, 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 confirmed
to be returned to normal, after re-assembling.
5. Leakage current check
(Safety for electrical shock hazard)
After
re-assembling
the
product,
always
perform
an
isolation
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 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, 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 exceed 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 Q2 10 W resistor paralleled by a 0.15 uF 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 ohms /volt,
or more
sensitivity.)
O.15uF
AC TYPE
Place
this probe
on each exposed
metal part.
WN
15002 10W
Good Earth Ground
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