Sharp LC-C3234U Service Manual - Page 2

LC-C3234U LSCAC3F23E4UTY PRECAUTION Service Manual IMPORTANT SERVICE SAFETY PRECAUTION Service work should be performed only by qualified service technicians who are thoroughly familiar with all safety checks and the servicing guidelines which follow: „WARNING 1. For continued safety, no modification of any circuit should be attempted. 2. Disconnect AC power before servicing. C A U T I O N : F O R C O N T I N U E D PROTECTION AGAINST A RISK OF FIRE REPLACE ONLY WITH SAME TYPE FUSE. F7101 (250V 6.3A) F7102 (250V 1A) • Use an AC voltmeter having with 5000 ohm per volt, or higher, sensitivity or measure the AC voltage drop across the resistor. • 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, etc.) and measure the AC voltage drop across the resistor. All checks must be repeated with the AC cord plug connection reversed. (If necessary, a nonpolarized adaptor plug must be used only for the purpose of completing these checks.) Any reading of 0.75 Vrms (this corresponds to 0.5 mA rms AC.) or more is excessive and indicates a potential shock hazard which must be corrected before returning the monitor to the owner. „BEFORE RETURNING THE RECEIVER (Fire & Shock Hazard) Before returning the receiver to the user, perform the following safety checks: DVM AC SCALE 1.5k ohm 10W 3. Inspect all lead dress to make certain that leads are not pinched, and check that hardware is not lodged between the chassis and other metal parts in the receiver. 4. Inspect all protective devices such as non-metallic control knobs, insulation materials, cabinet backs, adjustment and compartment covers or shields, isolation resistor-capacitor networks, mechanical insulators, etc. 0.15 µF TEST PROBE 5. 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. • Using two clip leads, connect a 1.5k ohm, 10 watt resistor paralleled by a 0.15µF capacitor in series with all exposed metal cabinet parts and a known earth ground, such as electrical conduit or electrical ground connected to an earth ground. TO EXPOSED METAL PARTS CONNECT TO KNOWN EARTH GROUND SAFETY NOTICE Many electrical and mechanical parts in LCD color television have special safety-related characteristics. For continued protection, replacement parts must be identical to those used in the original circuit. 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, etc. The use of a 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 or other hazards. Replacement parts which have these special safety characteristics are identified in this manual; electrical components having such features are identified by " " and shaded areas in the Replacement Parts List and Schematic Diagrams. i