Sharp 19C140 Manual de servicio - Página 3

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IMPORTANT SERVICE SAFETY PRECAUTION

BEFORE RETURNING THE RECEIVER

(Fire & Shock Hazard)

Before returning the receiver to the user, perform

the following safety checks.

1. Inspect all lead dress to make certain that leads are

not pinched or that hardware is not lodged between

the chassis and other metal parts in the receiver.

2. Inspect all protective devices such as non-metallic

control knobs, insulating materials, cabinet backs,

adjustment and compartment covers or shields,

isolation resistor-capacity networks, mechanical

insulators and etc.

3. To be sure that no shock hazard exists, check for

leakage current in the following manner.

» Plug the AC cord directly into a 120 volt AC outlet,

(Do not use an isolation transformer for this test).

» Using two clip leads, connect a 1.5k ohm, 10 watt

resistor paralleled by a 0.15mF capacitor in series

with all exposed metal cabinet parts and a known

earth ground, such as electrical conduit or electrical

ground connected to earth ground.

» Use an AC voltmeter having with 5000 ohm per volt,

or higher, sensitivity to measure the AC voltage drop

across the resistor.

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SAFETY NOTICE

Many electrical and mechanical parts in television

receivers have special safety-related characteristics.

These characteristics are often not evident from visual

inspection, nor can protection afforded by them be

necessarily increased by using replacement components

rated for higher voltage, wattage and etc.

Replacement parts which have these special safety

characteristics are identified in this manual; electrical

components having such features are identified by "å"

and shaded areas in the Replacement Parts Lists and

Schematic Diagrams.

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(Continued)

» Connect the resistor connection to all exposed metal

parts having a return to the chassis (antenna, metal

cabinet, screw heads, knobs and control shafts,

escutcheon and etc.) and measure the AC voltage

drop across the resistor.

AII checks must be repeated with the AC ine cord

plug connection reversed. (If necessary, a non-

polarized adapter plug must be used only for the

purpose of completing these check.)

Any current measured must not exceed 0.5 milliamp.

Any measurements not within the limits outlined

above indicate of a potential shock hazard and

corrective action must be taken before returning the

instrument to the customer.

TO EXPOSED

METAL PARTS

For continued protection, replacement parts must be

identical to those used in the original circuit. The use of

substitute replacement parts which do not have the same

safety characteristics as the factory recommended

replacement parts shown in this service manual, may

create shock, fire, X-radiation or other hazards.

19C140

1.5k ohm

10W

0.15 F

TEST PROBE

CONNECT TO

KNOWN EARTH

GROUND