HP-400A-Manual-sn-8504 电路图.pdf

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1、 HP Archive This vintage Hewlett Packard document was preserved and distributed by www. Please visit us on the web ! On-line curator: Glenn Robb This document is for FREE distribution only! RadioFans.CN 收音机爱 好者资料库 . INSTRUCTIONANDOPERATINGMANUAL FOR MODEL400A VACUUMTUBEVOLTMETER Serial8504andAbove H

2、EWLETT-PACKARDCOMPANY 395PAGEMILLROAD,PALOALTO,CALIFORNIA,U.S.A. RadioFans.CN 收音机爱 好者资料库 GeneralDescription TheModel400AVacuumTubeVoltmeterisanaccuratevoltmeterwith highsensitivityandhighinputimpedance.Alternatingcurrentvoltagesassmall as.005voltsandupto300voltsatfrequenciesfrom10cycles/sec.to1mega-

3、 cycle/sec.maybemeasuredwiththevoltmeter.Theinputimpedanceishigh enoughsoasnottodisturbthemajorityofcircuitsbeingmeasured. TheModel400Aisusefulforlaboratoryworkwherequickandaccurate measurementsofamplifiergain,networkresponsehumlevel,andoutputlevel aretobemade. Thehighervoltagerangesareusefulformeas

4、uringpowercircuitvolt- agesandhighfrequencyvoltagesinbroadcastandtelevisionequipment. CAUTION THEMAXIMUMVOLTAGEAPPLIEDTOTHEINPUTTERMI- NALSOFTHEMODEL400AVACUUMTUBEVOLTMETER MUSTNOTEXCEED600VOLTS,THESUMOFTHEDCVOLT- . o o WILLBREAKDOWNTHECAPACITORSINTHEINPUTSYS- TEMOFTHEINSTRUMENT. AGEANDTHEACPEAKVOLT

5、AGE.HIGHERVOLTAGES . o CAUTION ReplacementofElectrolyticCapacitors Theelectrolyticcapacitors(exceptC8,C12)inthisinstrumentarevery highqualitycapacitorswhichhaveausefullifeoffromfivetotenyears.Do notreplacethesecapacitorsunlesstheyareprovendefectivebyaccuratetests. PartsSubstitutions Difficultiesinpr

6、ocuringsomeofthepartsusedinthisinstrumentmay causetheelectricalorphysicalvaluestodeviatefromthoseshowninthisin- structionmanual.Thesesubstitutionshavebeenmadesoasnottoimpairthe performanceofthisinstrument.Wheneverreplacementofanyoftheseparts isnecessary,eitherthesubstitutevalueortheoriginalvaluemayb

7、eused. RadioFans.CN 收音机爱 好者资料库 INSTRUCTIONS MODEL400A VACUUMTUBEVOLTMETER Specifications VoltageRanges- VoltsFullScale(RMS)- ZD , J 20 13 I - .03.1.31 DB- 31030100300 -30-20-10o+10+20+30+40+50 FrequencyRange- 10cycles/sec.to1MC. Accuracy- 30/0offullscaleindicationonallranges,from10cycles/sec.to100Ke

8、. 50/0offullscaleindicationonallranges,from100Kcto1Mc. MeterCalibration MetercalibratedtoRMSvalueofasinewave. Linearvoltagescales0-IVand0-3V. Voltagerangesrelatedby10dbsteps ZeroLevel- 1milliwattinto600ohms VoltmeterStability- Linevoltagevariationsfrom105to125voltswillcauselessthan20/0 variationinre

9、adingonallfrequenciesbelow100Kcandlessthan30/0 onallfrequenciesbetween100Kcand1Mc. InputImpedance- Inputshuntcapacityapproximately251-1.I.1.f. Inputshuntresistance: .03to30voltsrange- 1megohm 100voltsrange- 3megohms 300voltsrange-2.4megohms OverloadCapacity- Meterwillnotbedamagedbyoccasionaloverload

10、sof100timesnormal. -1- PowerSupplyRating- Voltage-115volts Frequency-50/60cycles Watage-40watts OverallDimensions- 7-9/16widex9-1/21ighX10-1/4deep Weight 15pounds 0FeratingInstructions Inspection-= Thisinstrumenthasbeenthorougnlytestedandinspectedbeforebeing shippedandisreadyforusewhenreceived. Afte

11、rtheinstrumentisunpacked.itshouldbecarefullyinspectedfor damagereceivedintransit.Iianyshippingdamageisfound,followthepro- cedureoutlinedintheClaimforDamageinShipmentpageatthebackofthis instructionbook. ControlsandTerminals ON-Thistoggeswitchcontrolsthepowersuppliedtotheinstrument fromthepowerline.Wh

12、entheswitchisintheONposition,theredindicator willglow. DB-R,M.S.VOLTS - Tisrotaryswitchconnectsthepropermultiplier resistorsintothecircuitforthedesiredvoltagerange.Thepositionofthe switchindicatesthemeterscaleandthefullscalevoltageoftherangeinuse. TheswitchpositionalsoindicatestheDBlevel(instrumentc

13、onnectedacross 600ohms)whenthemeterpointerindicateszeroontheDBscale. InputTerminals-Thetwobindingposts,locatedinthelowerleftcorner ofthecontrolpanel,areconnectedtotheinputcircuitoftheinstrument.The lowerbindingpostisconnected0thechassis. CAUTION THEMAXIMUMVOLTAGEAPPLIEDTOTHEINPUTTERMI- NALSOFTHEMODE

14、L400AVACUUMTUBEVOLTMETER MUSTNOTEXCEED600VOLTS,THESUMOFTHEDCVOLT- , C1 o AGEANDTHEACPEAKVOL1.:AGE.HIGHERVOLTAGES WILLBREAKDOWNTHECAPACITORSINTHEINPUTSYS- TEMOFTHEINSTRUMENT -2- o ., FUSE-Thefuseholder,locatedonthebackofthechassis,containsa 1amperecartridgefuse.Thefusemaybereplacedbyunscrewingthefuse

15、holder andinsertinganewfuse. PowerCable-Thepowercableconsistsofthreeconductors.Twoof theseconductorscarrypowertotheinstrumentwhilethethirdconductor(green wire)isconnectedtotheinstrumentchassis.Thethirdwireprojectsfromthe cableneartheplugendofthecableandmaybeconnectedtoagroundwhenit isdesirabletohave

16、agroundedchassis. Operation- ZeroMeterIndication-Themeterpointermaynotcoincidewiththe zeroscalemarkwhentheinstrumentisturnedof.Thisconditionisnormal. Thezeroadjustmentscrewissetforoptimummetertrackingaccuracy andthenthescrewissealed. VoltageMeasurements-Plugthepowercableintoa115voltpowerline andturn

17、thetoggleswitchtoON.Allowtheinstrumentaboutfiveminutesto reachastateofstableoperation.SettheDB-R.M.S.VOLTSrangeswitchto thedesiredvoltagerangeandconnecttheinputterminalstothevoltagebeing measured.Themeterscalemultiplyingfactor(DB-R.M.S.VOLTSswitch positiondividedbythefullscalevalueofthemeterscaleinu

18、se)timesthemeter indicationequalsthevoltagebeingmeasured. Examples: A.100(DB-RMSVOLTSswitchposition)-+1(fullscalevalueofmeter scaleinuse)=100(Meterscalemultiplyingfactor) 100(Meterscalemultiplyingfactor)x.83(meterscaleindication)83 volts(measuredvoltage) B.30(DB-RMSVOLTSswitchposition)-+3(fullscalev

19、alueofmeter scaleinuse)=10(meterscalemultiplyingfactor) 10(meterscalemultiplyingfactor)x2.3(meterscaleindication)=23 volts(measuredvoltage) Asaprecautioninmaintainingaccuracyofmeasurement,itmustbekept inmindthattheinstrumentisanaverage-readingdevice.Althoughthecalibra- tiononthefaceoftheinstrumentis

20、markedRMSVOLTS,thissimplymeans thatthemeterwillreadthermsvalueofatruesiaewave.Ifthewaveformof thevoltagebeingmeasuredcontainsappreciableharmonicvoltagesorother spuriousvoltages,errorsinmeasurementwillbeencounteredofamagnitude indicatedbythefollowingtable. -3- %TrueRMSModel400APeakMeter HarmonicValue

21、IndicationIndication 0100100100 10%2nd100.510090to100 20%2nd102100-10280to120 50%2nd112100-11075to150 10%3rd100.596-10490to110 20%3rd10294-10880to120 50%3rd1 290-116108to150 DBMeasurement-Decibelmeasurementsaremadeinthesamewayas voltagemeasurementsexceptthattheDBscaleisusedandthemeasurements mustbem

22、adeacros600ohms,ifthe1milliwattacross600ohmsreference levelistobeused.Thedifferencebetweentwoormorevoltages,measuredin decibles,maybereaddirectlyfromtheModel400Aprovidedeachmeasurement ismadeacrossthesamevalueofimpedance.Thedecibellevelbeingmeasured isdeterminedbysumofdifferenceofthemeterscaleindica

23、tionandtherange switchindication.Theplusorminussignsbeforethemeterscalefigures,de- terminewhetherthemeterscaleindicationistobeaddedorsubtractedfrom thedecibellevelshownbytherangeswitch. Examples: C.Interpretingtherangeswitchpositionandmeterscaleindicationfor alevelof+12db.Measuredacros600ohmswithone

24、milliwattacross600 ohmsasthereferenceleveL +10db(DB-RMSVOLTSswitchpositionplus+2db(dbmeterscale indication)+12dbor +20db(DB-RMSVOLTSswitchposition)plus-8db(dbmet.erscale indicaion=12db D.Interpretingtherangeswitchpositionandmeterscaleindicationfor thedifferencebetweentwovoltages.measuredindecibels.a

25、crossthesame valueofimpedance. Voltagesequal-37dband+12db. -30db(DBRMSVOLTSswitchposition)plus-7db (dbmeterscaleindication-37db +10dbplus+2db(fromExampleC),.(-)+12db 49db(totaldecibeldiffer- encebetweenthetwo voltages) -4- .,.,. o ZeroMeterIndication-Themeterpointermaynotcoincidewiththe zeroscalemar

26、kwhentheinstrumentisturnedoff.Thisconditionisnormal. Thezeroadjustmentscrewissetforoptimummetertrackingaccuracy andthenthescrewissealedo Accessories Severalaccessoriesareavailablewhichmaybeusedtoextendthevolt- agerangeoftheModel400Aoradapttheinstrumenttomeasuresmallalterna- tingcurrentsoTheseaccesso

27、riesarenotsuppliedwiththeinstrumentbutmay bepurchasedfromtheHewlett-Packard800Theaccessoriesandtheirspecifi- cationsarelistedbelow0 Model452CapacitiveVoltageDivider ExtendsthevoltagerangeoftheModel400Ato25.000voltso Maximumvoltage-25.000volts FrequencyRange-25cycles/secoto20megacycles/sec. Accuracy-

28、3% DivisionRatio-1000;1 InputCapacity-15I.ll.lf Model470A-470FShuntResistors 100ohms 600ohms 1000ohms ShuntResistance currentmeasurements. Model 470D 470E 470F olohm 1ohm 10ohms ShuntResistanceModel TheseshuntresistorsadapttheModel400Afor Accuracy-l%of100.000cycles/seco 5%of2megacycles/seco MaximumP

29、owerDissipation- 1watt 470A 470B 470C CircuitDescriEtion ThecircuitoftheModel400AVacuumTubeVoltmeterconsistsofa cathodefoHowerinputstage.astabilizedamplifier.arectifierandmetersec- tion.andaregulatedpowersupplyo Thevoltageappliedtotheinputterminalsispassedthroughablocking capacitortothegridofthe6J5c

30、athode-followerinputstage.Thecathodere- sistorisatappedprecisionwirewoundresistorwhichservesasthevoltmeter multiplieronallbutthetwohighestranges.Onthelattertworangesahigh- resistancefrequency-compensatedvoltagedividerisswitchedacrosstheinput terminalsandaheadofthegridofthefirsttubeo Thecathodefollow

31、erfeedsintoabroad-bandresistance-coupledampli- fierusing6AC7tubes.Negativefeedbackisusedinthisamplifierinorderto -5- obtainhighsabilityanduniformresponseoverawidefrequencyrangepandto maketheamplihermoreindependeofvariationsintubecharacteristics. Fromtheamplifierheroltage1Spassedtoafullwaerecifierusi

32、ng a6H6duo-diodetube.Theind1catIngmeter1Sonnectedfromoneplatetothe opposItecathodeofthetubeandtherefore1Satuaedbyaportionoftheplate currenofthewod10des. Directcurrentfortheplatesuplyofthetubesinheinstrumentisob- ainedfromaonenionalful-waveTecifierfeedlngInoaresistance-capacity filter.AoltageregulatI

33、ngClrcuitarosstheoutpuoftherectifierkeepsthe plaesupploltageonsantoverawiderangeoflinevolages. Maintenane CoverandBottomPlateRemoval- Thecoe covertotheback isremoedbyuncrewlnghefourscrewswhichfastenthe fl:ejnst,rumet.adshdmgthecoverawayfromthepaneL ThebotomplateISfastenedtotheinstrumenwithfourscrews

34、ponein eachcornerofthepIae. TubeReplaement- Thereplar.:emerofubew1hae asighteffetuponthecalibrationof thismstrumepespeca.yatrequeniesbelow100KcoTubeswhichdiffer widelyfromtheaveragetypecharaCteristsanhoweve.Fpaffectcalibration atfrequenciesabove100Kepandforbisreason1idesirablethahecalibra- tionbeche

35、ckedIfpossib.ewhebAC7and6H6tubearereplaced. owandthenvwhe1replacingbAC7tubeapermanentdefflectionofthe meterpoinerWI:beobsened.tbtheinpuerminalsshortedandwhenthe newtubehasheated.Thi.condition15usuallyausedbycathode-heaterleak- ageandtheubeshouldberejecedinfarorofanoher. Whenreplacing6H6and/or6AC?ube

36、sitisdeirable0checkthevolt- ageresponseofhenewtubeiftheTalmeleisbeingoperatedfromanunregu- latedlinevotage.Thicheckcanbemadebyapp.ingaonstantvoltagetothe inputerminalsandvaryIngthe.ie0tage10volsrom115volts.Thevolt- meterreadingshou1dnohangebymoreban3%afrequenciesbelow100kc norbymore.han5%atfrequenle

37、sbelowonemegacycle.Tryanothertubeif necesary. CheckingCalibration Probabythemostacuraemethodwhichanbeusedinhefieldto checkthecahbrationoftheModel400Aisatestusingacathode-rayoscilloscope andafreshlycalibrateddynamometertypevoltmeer. -6- ,p- c c . c - ex: - l.T v: ex: ,p- l.T 0 .,. o o ., Afterthenewt

38、ubehasheatedintheModel400A,applyalow-frequency (50-60cpsvoltagesimultaneouslytoboththeModel400Aandthedynamometer/ typevoltmeters.Readingstothetwoinstrumentsshouldagreeclosely.Try anothertubeifnecessary. Next,calibratetheathode-raytubeoftheoscilloscopebyapplyinga low-frequencysinusoidalvoltagesimulta

39、neouslytothedynamometervoltmeter andtothevertical-deflectingelectrodesofthec-rtube.Nohorizontalsweep voltageshouldbeused.Directionsforconnectingtothedeflectingelectrodes ofthetubeareusuallygivenbythemanufactureroftheoscilloscope.Bymeas- uringthepeak=topeakdeflectionofthec-rtubetracewithagraphscreena

40、nd bynotingthereadingofthevoltmeter.thedeflectionvoltageofthec-rtubecan bequicklydetermined.Itisimportantthatthevoltageusedtocalibratethec-r tubebeessentiallysinusoidalandfreefromharmonics. NowconneheModel400Ainparallelwiththevertical-deflectingplates ofthe-rubeandaplysinusoidalvoltagesoffrequencies

41、uptoonemegacycle tothecombinaionofhewoinstruments.ThevoltageshownbytheModel400A shouldagreeloselyWlhhatmdiaedbythemagnitudeofdeflectionofthec-r tubetrae.Ifsuhisnothe(ase.ryanothernewtubeintheModel400Aand repeatheprocess. Theaboveproedurewi1gie areasonablecheckatallfrequencieswith- intherangeoftheMod

42、el400A.althoughaheckannotbemadeofsmallvolt- ages.Lowoltagerangesanbe.hekedbystartingwithavoltagewithinone ofherangescheckedontheosllloscopeandworkingdownward.Forexample, iftheaccuryandfreqencresponseofthe100voltrangeoftheModel400A haebehekedonheosilsope.applya25-01wavetotheModel400A a dnotetherading

43、onthelOO-volrange.Thenswichtothe30-voltrange andnoehabreadlngisorrec.Byexendingthisprocedure.allranges ofthelnstrumenanbeheked. Alhoughheaboemethodswlllnogieprecisionresults.theywill oftenproehelpfulindeterminingwhetherornotoldtubeshaveexceededtheir servielifeorewtubesaresaisfacorytouse. Beyondchagi

44、ngubes.iisnoreommendedhatrepairorcalibration ofhisinrmenbeaemptedihefield.beauseoftheelaborateequipment required.TheHewlet-PakardCompanywillrecalibratetheinstrumentquickly andanominalharge.seofh serviewillusuallysaveagreatdealoftime. -7- CI C5 R42)JI1- R21 6200 R20 NOTES: CONDITIONSOFDCVOLTAGEMEASUR

45、EMENT 1115VOLTS,5060CYCLEPOWERSUPPLY 2.MEASUREMENTTAKENBETWEENTHEINDICATEDPOINTS ANDCHASSISWITHAVOLTMETEROF100MEGOHMS INPUTRESISTANCE 3.SETDB-VOLTSR.M.S.SWITCHAT300V oIPANElCaNTRall JSCREWORIVERADJ.! -4=-CHASSIS CAPACITYINJ,1)J.FUNLESSOTHERWISENOTED K1000OHMS MIMEGOHM *,.ELECTRICALVALUEADJUSTEDATTHE

46、FACTORY. AVERAGEVALUESHOWN.PARTMAYBEOMITTED. 08-VOLTSR.M.S!SWITCH510bc CONSISTSOFTHREESWITCHSECTIONS(a,b,e)ONA COMMONSHAFT.THESWITCH1$VIEWEDFROMTHE REAROF THEINSTRUMENTWITHSECTION51cNEXTTOTHECONTROL PANEL iI6200Ipl RI9 620 CII RI8 22K +/10 51abcPOSITION VOLTS R32 II I .03 33K 2.1 3.3 4 I 3 R34J.-C14

47、0J.-CI4b 610 25K10ufT10uf 7 30 8100 9 300 R33 68K +2/5 RI7 56K.LC9b 1 40PI CIO R31 270K .ljJf RI4 22 +120 RI5 VB 003 :o=:Jri+210 V7 6S07 R30S 10K R13 100 C8. 50pfT.TC9056K r- 40Pf C7 RIO 82K C6 1.5-7 R7 2200 1M R5 2M .Q82jJf R6 2.163M C4 C3 25 R3 51 2.163 M 1.5-7 RI C2 5-20 SeeNotes -1.$ - R26 +290

48、V5 *R35 R24 I 5Y3GT TI 800 .- J: , RIlttlI.I I =- +;40 R291: t: .,410 IVvC15 1:C40UI10ul R23 M V4 1 INPUT SCHEMA11CDIAGRAM SER IAL85048 OFMODEL 400A ABOVE 8357 Model400ATopViewCoverRemoved t S1ABC (SEEFIG.2) I Model400ABottomViewBottomPlateRemoved *1 a: iu- 2 10, 10 o o o t NOTE:ALLCOMPONENTS EXCEPT

49、 CIaC2 ARE MOUNTEDON OPP.SIDEOFBOARD. RBI o o o C IIMOUNTEDON -IOPP. SIDEOF IBOARD. NOT IFICONNECTEDTO IELECTRICALLY. C15 o o RB2 Fig.LModel400AResistorBoardDetails PINS,VI C2C3R2 INPUT Fig.2.SlabcSwitchDetails TABLEOFREPLACEABLEPARTS Circuit Ref.Description -hp- StockNo. Mil. ,egohms1%,1W Resistor:fixed,composition, 2.163megohms,.:!:l%,1W Resistor:fixed,composition, 2200ohms,100/0,1/2W 31-2.163MGG TypeCP-l 3-316KGG TypeCP-l 24-75B GB5105 24-lMB GB1051 1-2MGG TypeCP-l .n-2.l63MGG TypeCP-l 23-2200B EB2221