Samsung HT-X250 Service Manual

Also see for HT-X250: Firmware update guide Instruction manual Instruction manual Instruction manual Service manual

1. PrecautionsFollow these safety, servicing and ESD precautions to prevent damage and protect against potential hazardssuch as electrical shock and X-rays.Samsung Electronics 1-11-1 Safety Precautions1. Be sure that all of the built-in protectivedevices are replaced.2. When reinstalling the chassis and itsassemblies, be sure to restore all protectivedevices, including control knobs andcompartment covers.3. Make sure that there are no cabinetopenings through which peopleparticularly children might insert fingersand contact dangerous voltages. Suchopenings include the spacing between thepicture tube and the cabinet mask,excessively wide cabinet ventilation slots,and improperly fitted back covers.4. Design Alteration Warning:Never alter or add to the mechanical orelectrical design of the unit. Example: Donot add auxiliary audio or video connec-tors. Such alterations might create a safetyhazard. Also, any design changes or addi-tions will void the manufacturer's warran-ty.5. Leakage Current Hot Check (Figure 1-1):Warning: Do not use an isolationtransformer during this test. Use a leakage-current tester or a metering system thatcomplies with American National StandardsInstitute (ANSI C101.1, Leakage Current forAppliances), and Underwriters Laboratories(UL Publication UL1410, 59.7).With the unit completely reassembled, plugthe AC line cord directly into a 120V ACoutlet. With the unit's AC switch first inthe ON position and then OFF, measure thecurrent between a known earth ground(metal water pipe, etc.) and all exposedmetal parts. Examples: Handle brackets,metal cabinets, screwheads and controlshafts. The current measured should notexceed 0.5 milliamp. Reverse the power-plug prongs in the AC outlet and repeat.6. Insulation Resistance Cold Check:(1) With the unit's AC plug disconnectedfrom the AC source, connect an electricaljumper across the two AC prongs. (2) Setthe power switch to ON. (3) Measure theresistance between the shorted AC plug andany exposed metallic parts. Example:Screwheads, antenna, control shafts orhandle brackets.If any of the exposed metallic parts has areturn path to the chassis, the measuredresistance should be between 1 and 5.2megohms. If there is no return path, themeasured resistance should be "infinite." Ifthe resistance is outside these limits, a shockhazard might exist. See Figure 1-2DeviceUnderTest(Reading shouldnot be above0.5mA)LeakageCurrantTesterEarthGroundTest allexposed metalsurfacesAlso test withplug reversed(using AC adapterplug as required)2-Wire CordAntennaTerminalExposedMetal Partohm OhmmeterFig. 1-1 AC Leakage TestFig. 1-2 Insulation Resistance TestAll manuals and user guides at all-guides.com