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COLORMONITORSyncMaster753DF(DF17K*)SyncMaster755DF(DF17J*)ManualSERVICECOLORMONITORCONTENTS1.Precautions2.ProductSpecifications3.Disassembly&Reassembly4.Alignment&Adjustments5.Troubleshooting6.ExplodedView&PartsList7.ElectricalPartsList8.BlockDiagram9.WiringDiagram10.SchematicDiagramsSamsungElectronicsCo.,Ltd.May2000PrintedinKoreaP/N:BH68-00129G-01WARNINGS1.Forcontinuedsafety,donotattempttomodifythecircuitboard.2.DisconnecttheACpowerbeforeservicing.3.Whenthechassisisoperating,semiconductorheatsinksarepotentialshockhazards.1-1-1ServicingtheHighVoltageVRandCRT:WARNING:AhighvoltageVRreplacedinthewrongdirectionmaycauseexcessiveX-rayemissions.Caution:WhenreplacingthehighvoltageadjustmentVR,itmustbefixedbyasolderingironafteritisproperlyset.1.Whenservicingthehighvoltagesystem,removethestaticchargebyconnectinga10kohmresistorinserieswithaninsulatedwire(suchasatestprobe)betweenthechassisandtheanodelead.2.IftheHVVRrequiresadjustment,(a)ReplacetheVRandadjustthehighvoltagetothespecification.(b)UseasolderingirontomelttheadjustmentcapontheHVVRtopreventanymovement.3.WhentroubleshootingamonitorwithexcessivelyHV,avoidbeingunnecessarilyclosetothemonitor.Donotoperatethemonitorforlongerthanisnecessarytolocatethecauseofexcessivevoltage.4.Highvoltageshouldalwaysbekeptattheratedvalue,nohigher.OnlywhenhighvoltageisexcessiveareX-rayscapableofpenetratingtheshelloftheCRT,includingtheleadinglassmaterial.OperationathighvoltagesmayalsocausefailureoftheCRTorhighvoltagecircuitry.5.WhentheHVregulatorisoperatingproperly,thereisnopossibilityofanX-rayproblem.MakesuretheHVdoesnotexceeditsspecifiedvalueandthatitisregulatingcorrectly.6.TheCRTisespeciallydesignedtoprohibitX-rayemissions.ToensurecontinuedX-rayprotection,replacetheCRTonlywithonethatisthesameorequivalenttypeastheoriginal.7.HandletheCRTonlywhenwearingshatterproofgogglesandaftercompletelydischargingthehighvoltageanode.8.DonotlifttheCRTbytheneck.1-1-2FireandShockHazard:Beforereturningthemonitortotheuser,performthefollowingsafetychecks:1.Inspecteachleaddresstomakecertainthattheleadsarenotpinchedorthathardwareisnotlodgedbetweenthechassisandothermetalpartsinthemonitor.2.Inspectallprotectivedevicessuchasnonmetalliccontrolknobs,insulatingmaterials,cabinetbacks,adjustmentandcompartmentcoversorshields,isolationresistor-capacitornetworks,mechanicalinsulators,etc.3.LeakageCurrentHotCheck(Figure1-1):WARNING:Donotuseanisolationtransformerduringthistest.UsealeakagecurrenttesterorameteringsystemthatcomplieswithAmericanNationalStandardsInstitute(ANSIC101.1,LeakageCurrentforAppliances),andUnderwritersLaboratories(ULPublicationUL1410,59.7).4.Withtheunitcompletelyreassembled,plugtheAClinecorddirectlyintoa120VACoutlet.Withtheunit’sACswitchfirstintheONpositionandthenOFF,measurethecurrentbetweenaknownearthground(metalwaterpipe,conduit,etc.)andallexposedmetalparts,including:metalcabinets,screwheadsandcontrolshafts.Thecurrentmeasuredshouldnotexceed0.5milliamp.Reversethepower-plugprongsintheACoutletandrepeatthetest.Figure1-1.LeakageCurrentTestCircuit1-1-4ProductSafetyNoticesSomeelectricalandmechanicalpartshavespecialsafety-relatedcharacteristicswhichareoftennotevidentfromvisualinspection.Theprotectiontheygivemaynotbeobtainedbyreplacingthemwithcomponentsratedforhighervoltage,wattage,etc.Partsthathavespecialsafetycharacteristicsareidentifiedbyonschematicsandpartslists.Asubstitutereplacementthatdoesnothavethesamesafetycharacteristicsastherecommendedreplacementpartmightcreateshock,fireand/orotherhazards.Productsafetyisunderreviewcontinuouslyandnewinstructionsareissuedwheneverappropriate.Componentsidentifiedbyonschematicsandpartslistsmustbesealedbyasolderingironafterreplacementandadjustment.SyncMaster753DF/755DF1-11Precautions1-1SafetyPrecautions!DEVICEUNDERTESTTESTALLEXPOSEDMETALSURFACES(READINGSHOULDNOTBEABOVE0.5mA)LEAKAGECURRENTTESTER2-WIRECORDALSOTESTWITHPLUGREVERSED(USINGACADAPTERPLUGASREQUIRED)EARTHGROUND1.Servicingprecautionsareprintedonthecabinet,andshouldbefollowedclosely.2.Alwaysunplugtheunit’sACpowercordfromtheACpowersourcebeforeattemptingto:(a)removeorreinstallanycomponentorassembly,(b)disconnectPCBplugsorconnectors,(c)connectalltestcomponentsinparallelwithanelectrolyticcapacitor.3.Somecomponentsareraisedabovetheprintedcircuitboardforsafety.Aninsulationtubeortapeissometimesused.Theinternalwiringissometimesclampedtopreventcontactwiththermallyhotcomponents.Reinstallallsuchelementstotheiroriginalposition.4.Afterservicing,alwayscheckthatthescrews,componentsandwiringhavebeencorrectlyreinstalled.Makesurethattheareaaroundtheservicedparthasnotbeendamaged.1.Immediatelybeforehandlinganysemiconductorcomponentsorassemblies,draintheelectrostaticchargefromyourbodybytouchingaknownearthground.Alternatively,wearadischargingwrist-strapdevice.Toavoidashockhazard,besuretoremovethewriststrapbeforeapplyingpowertothemonitor.2.AfterremovinganESD-equippedassembly,placeitonaconductivesurfacesuchasaluminumfoiltopreventaccumulationofanelectrostaticcharge.3.Donotusefreon-propelledchemicals.Thesecangenerateelectricalchargessufficie