Boonton_59维修电路原理图.pdf

-5ETS MEGACYC.LEETERMODEL59 . - - RadioFans.CN 收音机爱 好者资料库 OPERATINGINSTRUCTIONS MEASUREMENTSMODEL59 M_E_A_SU_R_EM_EN_T_S_CO_R_P_OR_A_TI_O_N BOONTONNEWJERSEY RadioFans.CN 收音机爱 好者资料库 Section1. SectionII. INDEXTOCONTENTS ListofIllusrations. Introduction Specifications OPERATINGINSTRUCTIONS: a.SettingUP b.SelectionofCoils c.AdjustmentofCoupling d.Modulation. e.UseofPhones. USEINRECEIVERDESIGNANDALIGNMENI . . . . Page 3 4 4 5 6 6 8 8 a.Video OUtput Design. 8 b.VideoDetectorFilterDesign . . . 8 c.VideoI.F.BandpassAmplifierDesignannAlignment 10 d.InputCircuitDesign and Alignment 11 SectionIII.USEINTRANSMITTEEDESIGNANDADJUSTMENT a.ApplicationtoAudio ModUlators. .12 b.UseinMasterOscillatorStages. 13 c.UseinTuningBufferAmplifierStages. . 13 d.FinalPowerAmplifierTuning 13 e.Neutralization14 f.Parasitics.15 SectionIV.USEINANIENNAADJUSlMENT IncludesTransmission Lines and Matching Stubs . 16 SectionV.MEASUREMENlOFC,L,M,ANDQ a.Measurement b.Measurement c.Measurement d.Measurement ofCapacitance ofInductance. ofMutual Inductance ofQ 18 18 20 21 SectionVI.SERVICEANDMAINTENANCE a.ReplacementofTubes b.CircuitFailure. 22 22 2. SectionVII.ACCURACY SummaryofDependentFactors . . . . . .24 RadioFans.CN 收音机爱 好者资料库 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. LITOFILLUSTRATIONS TypicalSetUpofModel 59. UseofInductiveCoupling UseofCapacitativeCoupling. TelevisionVideo OUtputStageArrangedforCarrier DifferenceSound OUtputDiscriminator . UseofModel59asTrace Marker VideoDetectorLowPassFilter. High PassFilterDesign ReactionMethod ofNeutralization TransmissionMethodofNeutralization CheckingforStandingWavesonTransmissionLines Page 5 - 6 7 7 9 9 10 11 14 15 16 11.CouplingtoQuarter-WaveStubs. . .16 12. 13. 14. 15. 16. 17. 18. CapacitanceChart MeasurementofCapacitance. Reactance-FrequencyChart MeasurementofMutualInductance. MeasurementofQ AdjustmentofTrimmer Schematic Diagram NOPARTOFTHISMANUALMAYBE REPRODUCEDINWHOLEORINPART EXCEPTBYPERMISSIONOF MEASUREMENTSCORP Copyright1947by MEASUREMENTSCORPORATION PrintedinU.S.A. 17 18 19 20 21 22 23 3. RadioFans.CN 收音机爱 好者资料库 4. GENERALDESCRIPTION INTRODUCTION TheMegacycle Meteris: Agriddipmeter Avariablefrequencyoscillator Anabsorptionwavemeter Anoscillatingdetector Atunedcircuitabsorptiondetectr Itconsistsofa compactoscillatorconnectedtoitspowersup- plyby asmallflexiblecord.Thetunedcircuitcoilismounted externallysothatitwillbeconvenientforcouplingtoothercir- cuits.Inserieswiththegridleakarea d-c microammeter and a jackforinsertionof a telephoneheadsetinthecircuit.Aswitch isprovidedtoremovetheplatevoltagefromtheoscillatortUbe, cbangingthetube from a triodeoscillatortoa diodedetector.The Model59ispromptlyacceptedasa mostusefultool.Itisasimple, accurate,andversatileinstrumentcapableofsavingmuchvaluable engineeringtime. SPECIFICATIONS Frequency Range: 2.2Me.to400Me.withsevenplug-incoils. Modulat1on: CWor120cyclesfixedatapproximately30%orexternal. Dimensions: PowerUnit5-1/8Wide;6-1/8high;7-1/2deep, wt.6-1/2Ibs. OscillatorUnit33/4dia.;2 deep; wt. 1lb. Power Supply: 117volts,50-60cycles,20watts. Tubes: Onetype955oscillator one type VR-150/30regulator onetype5Y3GTrectifier RadioFans.CN 收音机爱 好者资料库 SECTION I OPERATING INSTRUCTIONS a.Settingup: Adjustment oftheSENSITIVITYknobwill settheoscillatinggridcurrenttosomeconveni- entvalueonthe0to100scale. After30 secondswarmupperiodthemeter shouldindicatetotheleftifswitchisonDIODE, orupscaleifacoilispluggedintotheoscilla- torunitandswitchis,setonCWorMOD. Itisconvenienttoremovethecoilset fromitsstoragespaceinrearofthepowersupply andclipitinplaceasshowninFigurelAoThis permitsfreeaccesstothecoilsand prOVides a d%finiteplaceforunusedcoils. Figure1A MODEL59SET-UPFORUSE TheMegacycle Meterconsistsofthree Thepowersupply,coilset,andoscillator Donotallowunusedcoilstoliescattered aboutonthework bench.Theyareeasilylostor damaged.Thesecoilsareindividuallycalibrated foreachoscillatorunitandseria+lynumbered; thereforereplacementusuallyinvolvesre-calibra- tion.ForstoragepositionofcoilsseeFigurelB. Check powersupplyvoltageandfrequency. AllstandardModel59saredesignedoroperation on117volt,50-60cyclepower.Ifthesupplyis correct,pluginthepowercordandswitchonby flippingupthepowerswitchattherightsideof thepowerunit. units: unit. 5. RadioFans.CN 收音机爱 好者资料库 b.SelectionofCoils: Frequencyrangesaremarkedoneachcoil exceptforthetwohighestfrequencycoils.Fre- quencylimitsofthecorrespondingscalesare markedontheoscillatorunit.Afterinsertionof thedesiredcoil,itisadvisabletosetthetun- ing knobtomid-scale,andthenadjustthesensi- tivityknobtoapproximately50onthegridcur- rentmeter.Normalvariationofthegridcurrent withtuningwillthenusuallyremainonscaleover theentirerangeofthatparticuiarcoil.(Note: onsomelowfrequencycoilsitmaybenecessaryto readjustthesensitivityknobattheextremesof thetuningrange.) c.Adjustment of Coupling Eitherinductiveorcapacitivecouplingof the59 can bemadetocircuitundertest. For mosttunedcircuitsitmaybemore convenienttoutilizeinductivecoupling.A simple illustrationofatypicalcircuitisshoinFig- ure2.Thisrepresentsacommonby-passdifficulty whichgivesrisetodeadspotsinhighfrequency receiversandtransmitters.Maximumcoupling (and largestdipingridcurrent)willresultwiththe axisoftheoscillatorcoilatrightanglestothe currentflow.Foraccuratecheckingofthereson- antcircuitfrequency,thecouplingshouldbe loosened byincreasingtheseparationbetween the oscillatorcoilandthecircuitundertestuntil only a moderatedipingridcurrent(10to20%) resultswhentuningthroughresonance. Sometypesoftunedcircuitsarewell shieldedmagnetically,sothat-itisdifficultto utilizeinductivecoupling.Figure3ilustrates such acircuit.Thisco-axiallineresonantcir- cuitisselfshieldingandofsufficientlyhigh Figure1B STORAGEPOSITIONOFCOILS 6. RadioFans.CN 收音机爱 好者资料库 Figure2 -USEOFINDUCTIVECOUPLING Thisillustratesthearrangementoftheoscillatorcoilatrightangles tothecurrentflowformaximumcouplingtotheresonantcircuit. Qtopennittheuseofthecapacitativecoupling obtainedbyplacingtheopenorhot end ofthe circuitnearonecoiltenninaloftheModel 59. Thisstraycapacitancecouplingmaynotbesuffi- cientforloadedcircuits,suchasmight be used intelevisionpre-selectors,etc.Fortheseap- plications,itmaybenecessarytouseaoneor twomicromicrofaradcouplingcapacitor.Thiscan beobtainedbytwistingtogetheraninchortwo ofhook-upwire.Thiscapacitanceshouldbekept assmallaspossible,sinceitwillaffectthe frequencycalibrationaccuracyoftheModel 59. Fortunatelyitisnotusuallyrequiredthatloaded (lowQ)circuitsbelocatedasaccuratelyin frequencyashigherQones. Completelyenclosedresonantcavities usuallyhavesometypeofcouplingloopwhich can beutilizedwiththeaidofanauxiliaryex- ternaltransmissionlineandcouplingloopas-a linkcouplingarrangementforcouplinginductive- lytotheModel59.* *SeeAmateursHandbook, 1947Edition,Page44. Figure 3 -USEOFCAPACITIVECOUPLING Thisillustratescapacitivecoupling toaquarterwaveco-axialstub. 7. RadioFans.CN 收音机爱 好者资料库 d. Modulation: Internal120cyclemodulationcan beap- pliedbyturningtheswitchtoMOD.Thismayhelp identifythesignalfromthe59inthepresenceof othersignalswhenworkingOnreceivers,etc. Externalmodulationcan beappliedby astandard phonepluginthejackmarkedEXT.MOD.About 20volt(r.m.s.)arerequiredfor30%. e.Useof Phones: Phones can be pluggedintothePHONEjack forindicationofthedip.Asharpclickaccom- paniesthedipingridcurrentforconventional application. Ifindicationoffrequencyofanoscilla- torisrequired,thephoneswillpermituseasa highsensitivityoscillatingdetectorwithits resultantzerobeatmethod ofaccuratefrequency determination.Forsometypes,ofQmeasure- ment,.thismaybeusefulinmeasuringJ:.f(see SectionV(d).).Asanon-oscillating,diode detector(switchonDIODE)theidentificationof modulatedsignals,oscillatorharmonics, sound ofparasiticsofblockingcharacter,etc.will befoundveryuseful. SECTIONII USEINRECEIVERDESIGN AND ALIGNMENT AsatypicalapplicationoftheModel59,its useintheconstructionofatelevisionreceiver ispresentedherewith.Thisapplicationinvolves theconstructionofvideoamplifierswiththeir peakingcoils,lowpassfilters,highpassfilters, bandpassfilters,discriminators,traps,oscilla- tors,etc. a.Video Output Design: Inordertoselectasuitablepeakingar- rangementforthevideoamplifiertheactualinput andoutputcapacitancesshouldfirstbe measured (asdescribedinSectionV(a).)withtheModel 59. Nextbyreferencetoasuitablehandbook,* apeakingcircuitcan beselectedandthevalue$ ofpeakingcoilscalculated.Thesecoilscan be measuredwiththeModel59(asdescribedinSec- tionV(b).)Theirlowestself-resonantfrequency canalsobe measureddirectly.Itisdesirablein mostinstancesthatthisself-resonantfrequency beconsiderablyhigherthanthehighestfrequency tobetransmittedthroughtheVideoamplifier. Ifcarrierdifferencetypeofsoundisde- sired,thecircuitshowninFigure4maybeuseful. Thisutilizesseries-shunttypeofpeakingwithan inductivelycoupled4.5megacycletrapforsound takeoff.The4.5megacycletrapcircuitshould beresonatedbymeansoftheModel 59.Thefm discriminatorshouldbealignedby meansofa sweepgeneratorwiththe59servingasatrace *TermansRadioEngineersHandbook,Page420-2, FinksPrinciplesofTelevisionEngineering,page227-8. 8. marker.Thiscan be accomplished bymerelycoup- linginthe59tosecureabeatnotesuperimposed ontheoscilloscopetraceasshowninFigure5. Ifa sweepgeneratorisnot,available,the59can be used byfixingthecouplingtoL2andL3ata satisfactoryvaluetopermittakingad.c.dis- criminatorcharacteristicwiththeaidofa high resistanced.c.voltmeter(suchasorModel62). Thesecondary ofthdiscriminatorshould be tuned forcrossoverat4.5megacycles, whilethepri-, maryshouldbetunedforsymmetry ofthepositive andnegativepeaks.Ifnecessary,thecoupling betweentheprimaryand secondary should bead- justedtoseparatethepeaks byatleast200kilo- cyclesormore. Figure4indicatestheuseofd.c.trans- missionwithnegativepolarityinputvideosignal aswouldbeobtainedfrom adetectorshownin Figure6.Theuseofthisarrangementhasseveral advantages:suchas,economy oftubessincehigh levelvideoofthecorrectpolarityisavailable forsyncclippingwithoutextratUbes,noextra d.c.restoreranditstimeconstant,absenceof gridcurrentinpresenceofstrongsignal,sothat allinterferenceisessentiallyblack,etc. b. VideoDetectorFilterDesign: Improveddetectionefficiencyandoverall stabilitycanbeobtainedthroughtheuse of a simpleconstantKlowpassfilterbetweenthe RadioFans.CN 收音机爱 好者资料库 6AC7 VIDEO ,-e;R TOSYNC. CLIPPER B+ B+-_J- AUDIO. KINOSCOPE Note:SeeFinksPrinci- plesofTelevision Engineering,page 227-8,forformulas tofindLlandL2 when Cl andC2are known.Risusually 3000 ohmstappedat onethirdforsync. L3andthe50mmfd trimmeraremadeto resonateat4.5me. Onlyloosecoupling needbeusedbetween L3andL2tosatur- atethesoundlimi- ter.Tooclose couplingwillspoil thevideotransient response. Figure4 -TELEVISIONVIDEOOUTPUTSTAGEARRANGEDFOR CARRIERDIFFERENCESOUNDOUTPUTDISCRIMINATOR videodetectorandthevideoamplifierstageas showninFigure6.*Thedesignofthisfilter involvesfirstadeterminationoftheinputand outputcapacitanceswiththeModel 59(Section V(a);)thenacalculationoftheloadresist- ance fromthedesiredqandwidth. Anexaminationoftheequationsforthis filtershowsthattheresonantfrequencyofthe seriescoilinparallelwiththesumofthein- putandoutputcapacitancesshouldbetwicethe cutofffrequencyofthefilter.Thisrelation isquiteusefulinrememberingthedesignfor- mulaforlowpassfilters;forthUS,theproduct ofLandC(inductanceandcapacitance)arede- termined.Theotherrelationwithregardto impedancelevelisgiveninFigure6. Itisusuallynecessarytoaddabout5 mmfd.inputcapacitywhenuSingIN34typeVideo detectors,inordertosecureproperoperation ofthefilter.Thelowestself-resonantfre- quencyoftheseriescoilshouldbeatleastas highasthei.f.passbandinordertoobtain goodi.f.rejection.Iftheself-resonancedoes Networktoreduce markerwidthbynarrow- ingtransmissionband- widthofoscilloscope MOOEl ( Note:Adjustthe couplingof the/Iodel59 toL3for convenient markersize. OSCILLO- SCOPE *SeeTermansRadioEngineersHandbook,Page228. Figure5 -USEOFMODEL59ASTRACEMARKER 9. RadioFans.CN 收音机爱 好者资料库 feFREQUENCY. z o !C :) z . . 6 7 VIDEOOUTPUTAMP. 6AC18,.-_ I -1._ -r- I I _.- - R LASTVIDEO I.F.AMP. J,-+-, R=;i I c 1tYLC Whereettisthesumoftheinputandoutput capacities,andfcisthecutofffrequency. TypicalvalueofttRtt=2700 ohms. Figure6 -VIDEODETECTORLOWPASSFILTER occur,atthe1.f.frequency, arejectionpeakwill occuratthisfrequency.Thistypeoffilterthen resemblesthem-derivedtyperatherthanthe simpleconstant-kasshowninFigure6. Thevideodetectorispolarizedfornega- tiveoutputinordertooperateproperlywiththe singlevideostageshowninFigure4.Obviously thedetectorpolaritydoesnotaffecttheopera- tionofthefilter,however. c.VideoI.F.BandpassAmplifierDesign ancAlignment : (1)Staggertuned(singletunedcircuit) amplifierscanbeverysuccessfullyusedfortele- visioni.f.s;however,ithasbeenpointedoutby Wallman* andothersthatthedistributonofstag- geredfrequenciesandcorrectloadingforeach circuitcanbestbecalculatedbyattentionto minimumphasenon-linearity.Afterthecorrect frequencieshave beendetermined,eachtuned.cir- cuitcan beeasilyadjustedby means oftheModel 59; theftthecorrectloadresistorscan beplaced acrosseachcircuitandtheresultantcombination checkedforuniformityofamplituderesponseby meansofa sweepgeneratorandtheModel59asthe sweepmarker.Somesacrificeinstagegainresults fromtheuse ofstaggertunedcircuits.Ahopeless phasecharacteristicwillresult,ifchoiceof staggeredfrequenciesandloadingisbasedonlyon observationoftheresultantamplituderesponse. (2)Staggertunedamplifierscanalsobe madebyalternatingsingleand doubletunedcir- cuitswithproperchoiceofloadand peaksepara- tion.*Againthelocationofresonantfrequencies can be determined bytheModel59, andthesepara- tionofthedoubletunedpeaks can beadjustedby a temporaryreductioninloadingformoreaccurate indicationontheModel 59. (3) Doubletunedcircuitamplifiers!canbe adjustedbyfirstloadingdownone ofthecircuits andsettingtheunloadedcircuittoapproximately thecorrectcenterfrequency;thenloadingitand removingtheloadfromtheothercircuittopermit settingittothecorrectcenterfrequencyalso. Thenbothloadscan beappliedandthecouplingin- creased,ifnecessarytosecureproperbandwith. Thelocationandseparationbetween peaks canbe alsomeasuredwiththe59.Afterloadingand *Wallman,H.,StaggerTuned1.F.Amplifiers,RadiationLaboratoryReport#524,February,1944. Baum,R.F.,DesignofBroadBand1.F.Amplifiers,JournalofAppliedPhysics,Volume17, Pages519-72l. Wright,A.,TelevisionReceivers,RCAReview,l1arch,1947,Page19. *TermansRadioEngineersHandbook,Page172. !TermansRadioEngineersHandbook,Pages154-162. Larsen,11.J.andl1errill,L.L.,Capacitance-CoupledIntermediateFrequencyAmplifiers,ProceedingsoftheI.R.E., Page71,January,1947. 10. RadioFans.CN 收音机爱 好者资料库 couplingaQJusmennasbeenUlliveted,aslight retuningwillusuallybenecessary.Inchecking suchheavilyloadedcircuits,itisnecessaryto userathertightcouplingtotheModel59;this shouldbe doneinsuch a mannerastoavoidseri- ouslyshiftingthecalibratedfrequencyofthe59. (4)Tripletunedcircuitsandothertypes ofi.f.band-passamplifierscanusuallybead- justedina mannersimilartothatoutlinedabove fordoubletunedcircuits.