HP-3476B-Manual-Operating-Service 电路图.pdf

HP Archive This vintage Hewlett Packard document was preserved and distributed by www. Please visit us on the web ! Thanks to on-line curator: Larry Kohut RadioFans.CN 收音机爱 好者资料库 OPERATINGANDSERVICEMANUAL DIGITAL MULTIMETER 34768 Flio-HEWLETT PACKARD ;. . . . CD w.- RadioFans.CN 收音机爱 好者资料库 r-Flin-HEWLETT PACKARD OPERATINGANDSERVICEMANUAL MODEL34768 DIGITALMULTIMETER ForInstrumentSerialNumbersI652A07250andGreater Any changes madeininstruments manufactured after this print- ing will be found in a Manual Changes supplement supplied with this manual.Besuretoexamine this supplement,ifone exists for this manual, for any changes which apply to your instrument and record these changesinthe manual. WARNINGI Tohelpminimizethepossibilityofelectricalfireorshock hazards,donotexposethisinstrumenttorainorexcess moisture. Manual Part No. 03476-90006 Microfiche Part No. 03476-90056 Copyright Hewlett-Packard Company1976 P.O.Box 301, Loveland, Colorado 80537 U.S.A. Printed: November 1977 RadioFans.CN 收音机爱 好者资料库 FliOWHEWLETT r-PACKARD CERTIFICATION. Hewlett-Packard Company certifies that thisproduct met itspublishedspecifications at the timeofshipmentfrom the factory. Hewlett-Packard further certifies that its calibration measurementsaretraceable to the United StatesNa- tional BureauofStandards, to the extent allowed by the Bureaus calibration facility, and to the calibration facilities ofother International Standards Organization members. WARRANTY This Hewlett-Packard productiswarranted against defects in material and workmanship for a periodofone year from dateofshipment ,except that in the caseofcertain components listed in Section Iofthis manual, the warranty shall be for the specified period) . During the warranty period, Hewlett-Packard Company will, at its option, either repairorreplace products which prove to be defective. For warranty serviceorrepair, this product must be returned to a service facility designated by -hp-. Buyer shall prepay shipping charges to -hp- and -hp- shall pay shipping charges to return the product to Buyer. However, Buyer shall pay all shipping charges, duties,andtaxes for products returned to -hp- from another country. Hewlett-Packard warrants that its software and firmware designated by -hp- for use withaninstrument will execute its programming instructions when properly installed on that instrument. Hewlett-Packard does not warrant that the operationofthe instrument,orsoftware,orfirmware will be uninterrupted or error free. LIMITATIONOFWARRANTY The foregoing warranty shall not apply to defects resulting from improperorinadequate maintenancebyBuyer, Buyer-supplied software or interfacing, unauthorized modification or misuse, operation outsideofthe environmental specifications for the product,orimproper site preparation or maintenance. NOOTHERWARRANTYISEXPRESSEDORIMPLIED.HEWLETT-PACKARDSPECIFICALLY DISCLAIMSTHEIMPLIEDWARRANTIESOFMERCHANTABILITY AND FITNESS FOR APARTICULAR PURPOSE. EXCLUSIVE REMEDIES THEREMEDIES PROVIDED HEREIN ARE BUYERS SOLE AND EXCLUSIVE REMEDIES. HEWLETT- PACKARDSHALLNOTBELIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL,ORCONSE- QUENTIAL DAMAGES,WHETHERBASED ON CONTRACT, TORT, OR ANYOTHERLEGAL THEORY. ASSISTANCE Productmaintenanceagreementsandothercustomerassistance agreements are available forHewlett-Packard products. Foranyassistance,contactyournearestHewlett-PackardSalesandServiceOffice. Addresses are provided at the backofthis manual. 10/1/79 Model3476B TABLEOFCONTENTS TableofContents SectionPage I.GENERALINFORMATION1-1 1-1.Introduction1-1 1-3.Description . . . . . . . . . . . . . . . . . . . . .1-1 1-5.Specifications.1-1 1-7.InstrumentandManual Identification1-3/14 1-9.Options1-3/1-4 1-12. Accessories1-3/1-4 1-14. Safety Considerations1-3/14 SectionPage I!.INSTALLATION_2-1/2-2 2-1.Introduction2-1/2-2 2-3.Initial Inspection2-1/2-2 2-5.PowerRequirements2-1/2-2 2-7.EnvironmentalRequirements2-1/2-2 2-9.Repackaging forShipment2-1/2-2 2-13.PowerCordsandReceptacles2-1/2-2 SectionPage lII.OPERATINGINSTRUCTIONS_3-1 3-1.Introduction3-1 3-3.Turn-On3-1 3-5.Operation3-1 3-6.Overload/Overrange Indication3-1 3-8.Auto/HoldSwitch_3-1 3-11.AC Voltage Measurements3-1 3-14.DC Voltage Measurements_.3-2 3-17.ACCurrentMeasurements3-2 3-20.DCCurrentMeasurements3-2 3-23.Resistance Measurements3-2 3-26.BatteryOperation3-3 3-27.RechargingtheBattery3-3 3-29.OperatingTime3-3 3-31.LowBatteryIndication_.3-3 3-33.InputProtectionFuses3-3 3-35.AC LineandBatteryFuse Replacement. . . . . . . . . . . . . . .3-3 3-37.SemiconductorJunctionMeasurements.3-3 SectionPage IV.THEORYOFOPERATION.4-1/4-2 4-1.Introduction.4-1/4-2 4-3.Simplified Block Diagram Description (Figure4-1).4-1/4-2 SectionPage V.MAINTENANCE5-1 5-1.Introduction_5-1 5-3.Test EqUipment Required5,1 5-5.PerformanceTests5-1 5-6.DCVoltmeterAccuracyTest5-1 5-8.DCAmmeterAccuracy Test5-1 5-10.OhmsAccuracy Test5-2 5-12.AC Voltage Accuracy Test5-2 5-14.ACAmmeterAccuracy Test5-3 5-15.ACCommon-ModeRejection Test5-3 5-17.DCCommon-ModeRejection Test5-3 5-19.AdjustmentProcedure_.5-6 5-21.PowerSupplyAdjustment5-6 5-22.SubstrateAdjustment5-6 5-23.InputAmplifier ZeroAdjustment5-6 5-25.IntegratorAmplifier ZeroAdjustment.5-6 5-27.+DCVoltGainAdjustment_ 5-6 5-28.- DC Volt GainAdjustment5-6 5-29.ClockFrequencyAdjustment5-6 5-30.OhmsAdjustment5-7/5-8 5-3I.ACConverterGainandZero Adjustment_5-7/5-8 5-32.ACHighFrequencyAdjustment (.I1 V range)5-7/5-8 5-33.ChangingthePower LineOptions5-7/5-8 5-36.AC LineandBatteryFuse Replacement5-7/5-8 SectionPage V!.REPLACEABLEPARTS. . . . . . . . . . . . .6-1 6-1.Introduction6-1 64.OrderingInformation6-1 6-6.Non-ListedParts6-1 6-8.Parts Changes: . 6-I 6-10.ProprietaryParts6-1 SectionPage VII.TROUBLESHOOTINGANDCIRCUIT DIAGRAMS_7-1 7-1.Introduction7-1 7-3.PreliminaryTroubleshooting7-1 7-10.SchematicDiagrams7-2 7-12. Printed Circuit Assembly Exchange_.7-2 7-14.PrintedCircuit Board Removal_7-2 iii TableofContents iv LISTOFTABLES TablePage I-I.SpecificationsI-I 1-2.GeneralInformation, 1-2 1-3.Options_1-3/1-4 1-4.Accessories._1-3/1-4 5-1.RequiredTestEquipment5-0 5-2.DCVoltmeterAccuracyTest.5-1 5-3.DCAmmeterAccuracyTest5-2 5-4.OhmsAccuracyTest5-2 5-5.ACVoltage AccuracyTest5-3 5-6.ACAmmeterAccuracyTest5-3 6-1.StandardAbbreviations6-2 6-2.CodeListofManufacturers6-2 6-3.ReplaceableParts6-3 LISTOFILLUSTRATIONS Rre 2-1.Plug Caps2-1/2-2 3-I.Overload Indication3-1 3-2.MultimeterAutoranging3-1 3-3.ACVoltage Measurement3-1 3-4.DC VoltageMeasurement3-2 3-5.ACCurrentMeasurement_3-2 3-6.DCCurrentMeasurement3-2 3-7.ResistanceMeasurement3-2 3-8.LowBatteryIndication_3-3 3-9.LocationofControlsandConnectors3-4 4-1.Simplified Block Diagram_.4-1/4-2 5-1.DCAmmeterAccuracyTest5-2 5-2.OhmsAccuracyTest5-2 5-3.ACAmmeterAccuracy Test5-3 5-4.Common-ModeRejectionTest5-4 5-5.AdjustmentLocator.5-9/5-10 7-1.MultimeterSchematicDiagram7-5/7-6 7-2.PowerSupply7-7/7-8 Model3476B FliOWHEWLETT PACKARD SAFETYSUMMARY Thefollowinggeneralsafetyprecautionsmustbeobservedduringallphasesofoperation,service,andrepairofthis instrument.Failuretocomplywiththeseprecautionsorwithspecificwarningselsewhereinthismanualviolates safetystandardsofdesign,manufacture,andintendeduseoftheinstrument.HewlettPackardCompanyassumesno liabilityforthecustomersfailuretocomplywiththeserequirements.ThisisaSafetyClass1instrument. GROUNDTHEINSTRUMENT Tominimizeshockhazard,theinstrumentchassis andcabinetmustbeconnectedtoan elec- tricalground.Theinstrumentis equippedwithathree-conductoracpowercable.Thepower cablemusteitherbe pluggedintoanapprovedthree-contactelectricaloutletor usedwitha three-contacttotwo-contactadapterwiththegroundingwire(green)firmlyconnectedtoan electricalground(safetyground)atthepoweroutlet.Thepowerjackandmatingplugofthe powercablemeetInternationalElectrotechnicalCommission(IEC)safetystandards. DONOTOPERATEINANEXPLOSIVEATMOSPHERE Donotoperatetheinstrumentinthepresenceofflammablegases orfumes.Operationofany electricalinstrumentinsuchanenvironmentconstitutesadefinitesafetyhazard. KEEPAWAYFROMLIVECIRCUITS Operatingpersonnelmustnotremoveinstrumentcovers.Componentreplacementandinternal adjustmentsmustbe madebyqualifiedmaintenancepersonnel. Donotreplacecomponents withpowercableconnected.Undercertainconditions,dangerousvoltagesmayexistevenwith thepowercable removed.Toavoid injuries,alwaysdisconnectpoweranddischargecircuits beforetouchingthem. DONOTSERVICEORADJUSTALONE Donotattemptinternal service oradjustmentunlessanotherperson, capableofrenderingfirst aid andresuscitation,is present. DONOTSUBSTITUTEPARTSORMODIFYINSTRUMENT Becauseofthedangerofintroducingadditionalhazards,donotinstallsubstitutepartsorper- formanyunauthorizedmodificationtotheinstrument.ReturntheinstrumenttoaHewlett- Packard Sales and ServiceOfficeforservice and repairtoensurethatsafetyfeaturesare main- tained. DANGEROUSPROCEDUREWARNINGS Warnings,suchastheexamplebelow,precedepotentiallydangerousproceduresthroughout thismanual.Instructionscontainedinthewarningsmustbefollowed. IWARNING Dangerousvoltages,capableofcausingdeath,arepresentinthisinstrument.Useex tremecautionwhenhandling,testing,andadjusting. A SAFETYSYMBOLS GeneralDefinitionsofSafetySymbolsUsedOnEquipmentorInManuals. g 2 2 C; -. INPUTLEVEL(Vdc) 3476-8-1581 Figure3-2.Multimeter Autoranging. 3-10. In the HOLD position (IN)theMultimeter willreo main inthesame rangeaswhen the switch was depressed. 3-11.ACVoltageMeasurements. Toavoid possible damage to the Multimeter circuitry, theacinput voltage mustnotexceed 707 Vrms. 3-12. Set the Multimeter front panel controlsasfollows: DC/AC(:7:)(IN) VOLTS (V)_(IN) AUTO HOLDAUTO (OUT) AMPS(A) ANDkn(OUT) 3-13. Connect test leads from the Multimeter Vn(HI) andCOM(LOW) connectors tothevoltage under testas shown in Figure 3-3. VflCOMA ,-.lkV-.,I.IA_., MAMAX0 500V FUEx FUSE 32 1.5A 3476-8-4453 rv AC SOURCE Figure3-3.ACVoltage Measurement. 3-1 Section III 3-14.DCVoltageMeasurements. Toavoid possible damage to the Multimeter circuitry, the dc input voltage mustnotexceed 1000 Vdc. 3-15. Set the Multimeter front panel controls as follows: DC/AC(=)=(OUT) VOLTS (V)(IN) AUTO HOLDAUTO (OUT) AMP (A) ANDkn(OUT) 3-16. Connect test leads from the Multimeter V n (HI)and COM(LOW) connectors to the voltage under testasshown in Figure 3-4. VOCOMA ,-:IkV-.,-I./A-, MAX,-MAX0 500V FUExFUSE 32fn-A1.54 3476-8-4453 BATTERY Figure 3-4.DCVoltage Measurement. 3-17.ACCurrentMeasurements. Toavoid possible damage to the Multimeter,do notallow the voltageacrossthe Amps toCOM input terminals to exceed 250 V at any time. 3-18. Set the Multimeter front panel controlsasfollows: DC/AC(=)(IN) AMPS(A)(IN) AUTO HOLDAUTO (OUT) VOLTS (V) ANDkn(OUT) 3-19. Connect test leads from the Multimeter A andCOM connectorstothe current under test as shown in Figure 3-5. 3-20.DCCurrentMeasurements. Toavoid possibledamageto the Multimeter, do notallow the voltage across the Amps toCOM input terminalstoexceed 250 V at any time. 3-2 Model3476B Figure 3-5. ACCurrentMeasurement. 3-21. Set the Multimeter front panel controlsasfollows: DC/AC(=-=-=)(OUT) AMPS(A)(IN) AUTO HOLD,AUTO (OUT) VOLTS (V) ANDkn(OUT) 322. Connect test leads from the Multimeter A andCOM to the current under testasshown in Figure 3-6. Figure 3-6. DCCurrentMeasurement. 3-23.ResistanceMeasurements. 3-24. Set the Multimeter front panel controls as follows: kn(IN) AUTO HOLDAUTO (OUT) VOLTS (V) ANDAMP(A)(OUT) DC/AC(=)Either 3-25. Connect test leads from the Multimeter Vnand COMconnectors to the resistance under testasshown in Figure 3-7. VOCOMA ,-:IkV-.,-1.IA-, MAX,-MAX0 500V FuExFUSE 32iAI.SA 3476-8-4453 Av Figure37.Resistance Measurement. Model 3476B 3-26.BATTERYOPERATION. 3-27.RechargingtheBattery. 3-28. Battery rechargingisaccomplishedbythefollowing procedure: a.Verifythatthe ac power source (line) matches the power configurationofthe Multimeterbyreferringtothe power requirement label located below the ac receptacle. Ifit is incompatible, refer to Section V for power require- mentmodification instructions. b.With the Multimeter Power switch set to Charge (out), connect the ac line voltage. c.Asspecified in Table 1-2, the Multimeter will be fully recharged within14hours. NOTE Withthe Multimeter ON and the properacline voltage connected, the charge on the battery will be maintainedbya trickle charge current. This charge currentisnotsufficient to fully recharge the Battery in14hours. 3-29.OperatingTime. 3-30. With the Multimeterbatteryfully recharged, the typical operating timeiseight hours. 3-31.LowBatteryIndication. 3-32. A lowbatteryconditionisindicated when 5 decimal points appear on the displayasshown in Figure 3-8. At this time the Multimeter should be connected to ac line voltage to allow thebatterytorecharge. NOTE Multimeter accuracy specificationsarenotmet during Low Battery Indication. Section III b.Set the POWER switch to CHARGE (out). c.Allow the Multimetertofastchargefor a minimumoffive minutes. d.Afterthis period,acline operation may be resumed. e.Donotbegin battery operation until the batteryisfully recharged. 3-33.InputProtectionFuses. 3-34. The AMPS inputisprotectedbya1.5A250V fuse andtheOHMSinputisprotectedbya32rnA250V fuse. These fuses are located behindtheslidingInputPanelas shown in Figure3-9,0, , .Replacementofthese fuses is accomplishedbythe following procedure: a.Slide the Input Panel firmly toward the backofthe Multimeter until the fusesprotrude. b.Remove and replace faulty fuse. Toavoid possible damage to the Multimeter, insure that the correct fusesareused forre- placement inthe InputProtection circuit. c.Push fuses firmly into their receptacles and slide the InputPanel forwardtohold fusesinplace and align the input jacks. NOTE Multimeter test lead banana plugscanbe used asa tool to hold the fusesinplace while sliding the Input Panel forward. 3-35.ACLineandBatteryFuseReplacement 3-36. Refer to Section V for instruction on the replace- mentofac line andbatteryfuses. 3-37.SEMICONOUCTORJUNCTIONMEASUREMENTS. Figure3-8.Low Battery Indication. NOTE Ifthe Multimeterisinadvertently left on and becomes completely discharged, the following procedure should be followed before using the Multimeter: a.Connect the Multimeter to the properacline voltage. 3-38. Due to the lowoutputcurrent on the higher ohms ranges, the34768must bedownranged to the lowest ohms range in order to measure semiconductorjunction(diode) resistance. This can be easily accomplished by the following procedure: a.To measuretheforward resistance, connect the cath- odeofthediode to theCOMterminal and the anode tothe nvterminal. b.Press the Apushbutton.This causes the instrument to downrange. 3-3 SectionJJl c.Press thekDpushbuttonand read the forward resis- tance on the display. Model3476B d.Tomeasure the reverse resistanceofa diode, reverse theinputconnections to the diode and repeat Stepsband c. 3476-8-4421 13 3476-8-4422 NOTE 0) panel and arefuseslocatedbehindsliding CD CD OISPLY:Fivesection,7 segment LE 0readout. PowerChargelOnSw