HarmanKardon-TU950-tun-维修说明书手册含电器原理图

TU950LEAKAGE TESTBefore returning the unit to the user,perform theUsing two clip leads,connects a 1500 ohm,following safety checks:10-watt resistor paralleled by a 0.15uF1.Inspect all lead dress to makes certain thatcapacitor,in series with all exposed metalleads are not pinched or that hardware is notcabinet parts and a known earth ground,suchlodged between the chassis and other metallicas a water pipe or conduit.Use a VTVM orparts in the unit.VOM with 1000 ohms per volt,or higher2.Be sure that any protective devices such assensitivity to measure the AC voltage dropnonmetallic control knobs,insulatingacross the resistor.(see diagram)Move thefishpapers,cabinet backs,adjustment andresistor connection to each exposed metalcompartment covers or shields,isolationpart having a return path to the chassisresistor-capacity networks,mechanical(antenna,metal cabinet,screw heads,knobsinsulators,etc.Which were removed forand control shafts,escutcheon,etc.)andservicing are properly reinstalled.measure the Ac voltage drop across the3.Be sure that no shock hazard exists;check forresistor.(This test should be performed withleakage current using Simpson Model 229the power switch in both the on and offLeakage Tester,standard equipment item no.positions.)21641,RCA model WT540A or use alternateA reading of 0.35 volt RMS or more ismethod as follows:plug the power cordexcessive and indicates a potential shockdirectly into a 230-volt AC receptacle (do nothazard which must be corrected beforeuse an isolation transformer for this test).returning the unit to the owner.SIMPSON MODEL 229 ETC.FOR LEAKAGE TESTTO EACH EXPOSEDTO AC GROUND SUCHMETAL SURFACE OFAS WATER PIPE BX CABLEUNIT UNDER TESTHIGHGROUNDCONDUIT ETC.VOLTAGELEADOR+LEADVTVM-O AC SCALEO1.5KΩ10W0.15ufTEST PROBETO EXPOSEDCONNECT TO KNOWNMETALIC PARTSEARTH GROUND2