Samsung 03 Precations free download

File name 03_Precations.pdf

1. Precautions Follow these safety, servicing and ESD precautions to prevent damage and protect against potential hazards such as electrical shock and X-rays. 1-1 Safety Precautions 1. Be sure that all of the built-in protective devices are replaced. 2. When reinstalling the chassis and its assemblies, be sure to restore all protective devices, including control knobs and compartment covers. 3. Make sure that there are no cabinet openings through which people-- particularly children--might insert fingers and contact dangerous voltages. Such openings include the spacing between the picture tube and the cabinet mask, excessively wide cabinet ventilation slots, and improperly fitted back covers. Fig. 1-1 AC Leakage Test 4. Design Alteration Warning: 6. Insulation Resistance Cold Check: Never alter or add to the mechanical or (1) With the unit's AC plug disconnected electrical design of the unit. Example: Do from the AC source, connect an electrical not add auxiliary audio or video connec- jumper across the two AC prongs. (2) Set tors. Such alterations might create a safety the power switch to ON. (3) Measure the hazard. Also, any design changes or addi- resistance between the shorted AC plug and tions will void the manufacturer's warran- any exposed metallic parts. Example: ty. Screwheads, antenna, control shafts or handle brackets. 5. Leakage Current Hot Check (Figure 1-1): Warning: Do not use an isolation If any of the exposed metallic parts has a transformer during this test. Use a leakage- return path to the chassis, the measured current tester or a metering system that resistance should be between 1 and 5.2 complies with American National Standards megohms. If there is no return path, the Institute (ANSI C101.1, Leakage Current for measured resistance should be "infinite." If Appliances), and Underwriters Laboratories the resistance is outside these limits, a shock (UL Publication UL1410, 59.7). hazard might exist. See Figure 1-2 With the unit completely reassembled, plug the AC line cord directly into a 120V AC outlet. With the unit's AC switch first in the ON position and then OFF, measure the current between a known earth ground (metal water pipe, etc.) and all exposed metal parts. Examples: Handle brackets, metal cabinets, screwheads and control shafts. The current measured should not exceed 0.5 milliamp. Reverse the power- plug prongs in the AC outlet and repeat.