DMTech DML-4120S, Руководство по обслуживанию

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1. Precautions
Prior to shipment from the factory, the products are strictly inspected to conform with the recognized product safety
and electrical codes of the countries in which they are to be sold. However, in order to maintain such compliance, it
is equally important to implement the following precautions when a set is being serviced.
1-1
SAFETY PRECAUTION
WARNING : Service should not be attempted by anyone unfamiliar with the necessary precautions on this TV.
The following are the necessary precautions to be observed before servicing this chassis.
1. An isolation Transformer should be connected in the power line between the TV and the AC line before any
service is performed on the TV.
2. When replacing a chassis in the cabinet, always be certain that all the protective devices are put back in
place, such as; non-metallic control knobs, insulating covers, shields, isolation resistor-capacitor network
etc.
3. Before returning the set to the customer, always perform an AC leakage current check on the exposed
metallic parts of the cabinet, such as terminals, screwheads, metal overlays, control shafts etc. to be sure
the set is safe to operate without danger of electrical shock. Plug the AC line cord directly into a AC outlet
(do not use a line isolation transformer during this check). Use an AC voltmeter having 5000
AC VOLTMETER
Good earth ground
such as a water
pipe, conduit, etc.
1500
10W
0.15 F
Place this probe on
each exposed
metallic part.
per volt or
more sensitivity in the following manner: Connect a 1500
10W resistor, paralleled by a 0.15 F, AC type capacitor,
between a known good earth ground (water pipe, con-
duit, etc.) and the exposed metallic parts, one at a time.
Measure the AC voltage across the combination of 1500
resistor and 0.15 F capacitor. Reverse the AC plug at
the AC outlet and repeat AC voltage measurements for
each exposed metallic part. Voltage measured must not
exceed 5.25V(rms). This corresponds to 3.5 mA(AC). Any
value exceeding this limit constitutes a potential shock
hazard and must be corrected immediately.
PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in this chassis have special safety-related characteristics. These charac-
teristics are often passed unnoticed by a visual inspection and the protection afforded by them cannot neces-
sarily be obtained by using replacement components rated for higher voltage, wattage, etc. Replacement parts
which have these special safety characteristics are identified in this manual and its supplements; electrical
components having such features are identified by the international hazard symbols on the schematic diagram
and the parts list.
Before replacing any of these components, read the parts list in this manual carefully
.
The use of substitute
replacement parts which do not have the same safety characteristics as specified in the parts list may create
shock, fire or other hazards.
DANGER
The components such as the power supply and FL inverter carry high voltages. When you partially disas-
semble the computer and turn on the components, use extreme care not to touch the connectors and compo-
nents to avoid the risk of electrical shock. Do not disassemble individual components during first-level mainte-
nance.
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