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1.1 Safety Precautions
(1) This 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 characteris-
tics 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 (
on the Parts List in the Service Manual. The use of a sub-
stitute replacement 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 reassembling.
(5) Leakage 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
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 parts of the cabinet, particu-
larly 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.).
• 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 sen-
sitivity in the following manner. Connect a 1,500
resistor paralleled by a 0.15
tween an exposed metal part and a known good earth
ground.
SECTION 1
Important safety precautions
)
10W
F AC-type capacitor be-
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. Voltage measured any must
not exceed 0.75 V AC (r.m.s.). This corresponds to 0.5
mA AC (r.m.s.).
1.2 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 lo-
cal voltage.
1.3 Caution
Burrs formed during molding may be left over on some
parts of the chassis.
Therefore, pay attention to such burrs in the case of pre-
forming repair of this system.
1.4 Critical parts for safety
In regard with component parts appearing on the silk-screen
printed side (parts side) of the PWB diagrams, the parts that are
printed over with black such as the resistor (
and ICP (
) or identified by the "
for safety.
When replacing them, be sure to use the parts of the same type
and rating as specified by the manufacturer. (Except the JC version)
VS-DT7R
), diode (
)
" mark nearby are critical
3
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