
1.Precautions
1.Precautions
1.1.SafetyPrecautions
1)Beforereturninganinstrumenttothecustomer,alwaysmakeasafetycheckoftheentireinstrument,including,butnot
limitedto,thefollowingitems:
a)Besurethatnobuilt-inprotectivedevicesaredefectiveorhavebeendefeatedduringservicing
i)Protectiveshieldsareprovidedtoprotectboththetechnicianandthecustomer.Correctlyreplaceallmissing
protectiveshields,includinganyremovedforservicingconvenience.
ii)Whenreinstallingthechassisand/orotherassemblyinthecabinet,besuretoputbackinplaceallprotective
devices,including,butnotlimitedto,nonmetalliccontrolknobs,insulatingshpapers,adjustmentand
compartmentcovers/shields,andisolationresistor/capacitornetworks.Donotoperatethisinstrumentorpermit
ittobeoperatedwithoutallprotectivedevicescorrectlyinstalledandfunctioning.
b)Besurethattherearenocabinetopeningsthroughwhichadultsorchildrenmightbeabletoinserttheirngersand
contactahazardousvoltage.Suchopeningsinclude,butarenotlimitedto,excessivelywidecabinetventilation
slots,andanimproperlyttedand/orincorrectlysecuredcabinetbackcover.
c)LeakageCurrentHotCheck—Withtheinstrumentcompletelyreassembled,plugtheAClinecorddirectlyintoa
230V(220V~240V)ACoutlet.(Donotuseanisolationtransformerduringthistest.)
UsealeakagecurrenttesterorameteringsystemthatcomplieswithAmericanNationalStandardInstitute(ANSI)
C101.1LeakageCurrentforAppliancesandUnderwritersLaboratories(UL)1270(40.7).Withtheinstrument’s
ACswitchrstintheONpositionandthenintheOFFposition,measurefromaknownearthground(metal
waterpipe,conduit,etc.)toallexposedmetalpartsoftheinstrument(antennas,handlebrackets,metalcabinets,
screwheads,metallicoverlays,controlshafts,etc.),especiallyanyexposedmetalpartsthatofferanelectrical
returnpathtothechassis.
Anycurrentmeasuredmustnotexceed0.5mA.
Reversetheinstrumentpowercordplugintheoutletandrepeatthetest.See
Anymeasurementsnotwithinthelimitsspeciedhereinindicateapotentialshockhazardthatmustbeeliminated
beforereturningtheinstrumenttothecustomer.
Figure1.1ACLeakageTest
d)InsulationResistanceTestColdCheck—(1)Unplugthepowersupplycordandconnectajumperwirebetween
thetwoprongsoftheplug.(2)Turnonthepowerswitchoftheinstrument.(3)Measuretheresistancewith
anohmmeterbetweenthejumperedACplugandallexposedmetalliccabinetpartsontheinstrument,suchas
screwheads,antenna,controlshafts,handlebrackets,etc.Whenanexposedmetallicparthasareturnpathtothe
chassis,thereadingshouldbebetween1and5.2megohm.Whenthereisnoreturnpathtothechassis,thereading
mustbeinnite.Ifthereadingisnotwithinthelimitsspecied,thereisthepossibilityofashockhazard,andthe
instrumentmustberepairedandrecheckedbeforeitisreturnedtothecustomer.See
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