1-1-1 Warnings1. For continued safety, do not attempt to modify thecircuit board.2. Disconnect the AC power and DC Power Jackbefore servicing.3. When the chassis is operating, semiconductorheatsinks are potential shock hazards.1-1-2 Servicing the LCD Monitor1. When servicing the LCD Monitor, remove the staticcharge by connecting a 10k ohm resistor in serieswith an insulated wire (such as a test probe)between the chassis and the anode lead.(Disconnect the AC line cord from the AC outlet.)2. It is essential that service technicians have anaccurate voltage meter available at all times. Checkthe calibration of this meter periodically.1-1-3 Fire and Shock HazardBefore returning the monitor to the user, perform thefollowing safety checks:1. Inspect each lead dress to make certain that theleads are not pinched or that hardware is notlodged between the chassis and other metal parts inthe monitor.2. Inspect all protective devices such as nonmetalliccontrol knobs, insulating materials, cabinet backs,adjustment and compartment covers or shields,isolation resistor-capacitor networks, mechanicalinsulators, etc.3. Leakage Current Hot Check (Figure 1-1): WARNING:Do not use an isolation transformer during this test.Use a leakage current tester or a metering systemthat complies with American National StandardsInstitute (ANSI C101.1, Leakage Current forAppliances), and Underwriters Laboratories (ULPublication UL1410, 59.7).Figure 1-1. Leakage Current Test Circuit4. With the unit completely reassembled, plug the ACline cord directly into a 120V AC outlet. With theunit’s AC switch first in the ON position and thenOFF, measure the current between a known earthground (metal water pipe, conduit, etc.) and allexposed metal parts, including: metal cabinets,screwheads and control shafts. The currentmeasured should not exceed 0.5 milliamp. Reversethe power-plug prongs in the AC outlet and repeatthe test.1-1-4 Product Safety NoticesSome electrical and mechanical parts have specialsafety-related characteristics which are often notevident from visual inspection. The protection they givemay not be obtained by replacing them withcomponents rated for higher voltage, wattage, etc. Partsthat have special safety characteristics are identified byon schematics and parts lists. A substitutereplacement that does not have the same safetycharacteristics as the recommended replacement partmight create shock, fire and / or other hazards. Productsafety is under review continuously and newinstructions are issued whenever appropriate.SyncMaster 33*TFT/53*TFT 1-11 PrecautionsFollow these safety, servicing and ESD precautions to prevent damage and to protect against potential hazards such aselectrical shock.1-1 Safety PrecautionsDEVICEUNDERTESTTEST ALLEXPOSED METALSURFACES(READING SHOULDNOT BE ABOVE 0.5mA)LEAKAGECURRENTTESTER2-WIRE CORDALSO TEST WITHPLUG REVERSED(USING AC ADAPTERPLUG AS REQUIRED) EARTHGROUND!