Boonton_59维修电路原理图.pdf

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1、-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

2、 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.USEINTR

3、ANSMITTEEDESIGNANDADJUSTMENT 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.

4、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

5、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 Reactio

6、nMethod 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 MeasurementofMutualInductanc

7、e. 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 Mete

8、ris: Agriddipmeter Avariablefrequencyoscillator Anabsorptionwavemeter Anoscillatingdetector Atunedcircuitabsorptiondetectr Itconsistsofa compactoscillatorconnectedtoitspowersup- plyby asmallflexiblecord.Thetunedcircuitcoilismounted externallysothatitwillbeconvenientforcouplingtoothercir- cuits.Inser

9、ieswiththegridleakarea d-c microammeter and a jackforinsertionof a telephoneheadsetinthecircuit.Aswitch isprovidedtoremovetheplatevoltagefromtheoscillatortUbe, cbangingthetube from a triodeoscillatortoa diodedetector.The Model59ispromptlyacceptedasa mostusefultool.Itisasimple, accurate,andversatilei

10、nstrumentcapableofsavingmuchvaluable 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

11、: 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 seconds

12、warmupperiodthemeter shouldindicatetotheleftifswitchisonDIODE, orupscaleifacoilispluggedintotheoscilla- torunitandswitchis,setonCWorMOD. Itisconvenienttoremovethecoilset fromitsstoragespaceinrearofthepowersupply andclipitinplaceasshowninFigurelAoThis permitsfreeaccesstothecoilsand prOVides a d%finit

13、eplaceforunusedcoils. Figure1A MODEL59SET-UPFORUSE TheMegacycle Meterconsistsofthree Thepowersupply,coilset,andoscillator Donotallowunusedcoilstoliescattered aboutonthework bench.Theyareeasilylostor damaged.Thesecoilsareindividuallycalibrated foreachoscillatorunitandseria+lynumbered; thereforereplac

14、ementusuallyinvolvesre-calibra- tion.ForstoragepositionofcoilsseeFigurelB. Check powersupplyvoltageandfrequency. AllstandardModel59saredesignedoroperation on117volt,50-60cyclepower.Ifthesupplyis correct,pluginthepowercordandswitchonby flippingupthepowerswitchattherightsideof thepowerunit. units: uni

15、t. 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- tivity

16、knobtoapproximately50onthegridcur- rentmeter.Normalvariationofthegridcurrent withtuningwillthenusuallyremainonscaleover theentirerangeofthatparticuiarcoil.(Note: onsomelowfrequencycoilsitmaybenecessaryto readjustthesensitivityknobattheextremesof thetuningrange.) c.Adjustment of Coupling Eitherinduct

17、iveorcapacitivecouplingof the59 can bemadetocircuitundertest. For mosttunedcircuitsitmaybemore convenienttoutilizeinductivecoupling.A simple illustrationofatypicalcircuitisshoinFig- ure2.Thisrepresentsacommonby-passdifficulty whichgivesrisetodeadspotsinhighfrequency receiversandtransmitters.Maximumc

18、oupling (and largestdipingridcurrent)willresultwiththe axisoftheoscillatorcoilatrightanglestothe currentflow.Foraccuratecheckingofthereson- antcircuitfrequency,thecouplingshouldbe loosened byincreasingtheseparationbetween the oscillatorcoilandthecircuitundertestuntil only a moderatedipingridcurrent(

19、10to20%) resultswhentuningthroughresonance. Sometypesoftunedcircuitsarewell shieldedmagnetically,sothat-itisdifficultto utilizeinductivecoupling.Figure3ilustrates such acircuit.Thisco-axiallineresonantcir- cuitisselfshieldingandofsufficientlyhigh Figure1B STORAGEPOSITIONOFCOILS 6. RadioFans.CN 收音机爱

20、好者资料库 Figure2 -USEOFINDUCTIVECOUPLING Thisillustratesthearrangementoftheoscillatorcoilatrightangles tothecurrentflowformaximumcouplingtotheresonantcircuit. Qtopennittheuseofthecapacitativecoupling obtainedbyplacingtheopenorhot end ofthe circuitnearonecoiltenninaloftheModel 59. Thisstraycapacitanceco

21、uplingmaynotbesuffi- cientforloadedcircuits,suchasmight be used intelevisionpre-selectors,etc.Fortheseap- plications,itmaybenecessarytouseaoneor twomicromicrofaradcouplingcapacitor.Thiscan beobtainedbytwistingtogetheraninchortwo ofhook-upwire.Thiscapacitanceshouldbekept assmallaspossible,sinceitwill

22、affectthe frequencycalibrationaccuracyoftheModel 59. Fortunatelyitisnotusuallyrequiredthatloaded (lowQ)circuitsbelocatedasaccuratelyin frequencyashigherQones. Completelyenclosedresonantcavities usuallyhavesometypeofcouplingloopwhich can beutilizedwiththeaidofanauxiliaryex- ternaltransmissionlineandc

23、ouplingloopas-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- pliedb

24、yturningtheswitchtoMOD.Thismayhelp identifythesignalfromthe59inthepresenceof othersignalswhenworkingOnreceivers,etc. Externalmodulationcan beappliedby astandard phonepluginthejackmarkedEXT.MOD.About 20volt(r.m.s.)arerequiredfor30%. e.Useof Phones: Phones can be pluggedintothePHONEjack forindicationo

25、fthedip.Asharpclickaccom- paniesthedipingridcurrentforconventional application. Ifindicationoffrequencyofanoscilla- torisrequired,thephoneswillpermituseasa highsensitivityoscillatingdetectorwithits resultantzerobeatmethod ofaccuratefrequency determination.Forsometypes,ofQmeasure- ment,.thismaybeusef

26、ulinmeasuringJ:.f(see SectionV(d).).Asanon-oscillating,diode detector(switchonDIODE)theidentificationof modulatedsignals,oscillatorharmonics, sound ofparasiticsofblockingcharacter,etc.will befoundveryuseful. SECTIONII USEINRECEIVERDESIGN AND ALIGNMENT AsatypicalapplicationoftheModel59,its useintheco

27、nstructionofatelevisionreceiver ispresentedherewith.Thisapplicationinvolves theconstructionofvideoamplifierswiththeir peakingcoils,lowpassfilters,highpassfilters, bandpassfilters,discriminators,traps,oscilla- tors,etc. a.Video Output Design: Inordertoselectasuitablepeakingar- rangementforthevideoamp

28、lifiertheactualinput andoutputcapacitancesshouldfirstbe measured (asdescribedinSectionV(a).)withtheModel 59. Nextbyreferencetoasuitablehandbook,* apeakingcircuitcan beselectedandthevalue$ ofpeakingcoilscalculated.Thesecoilscan be measuredwiththeModel59(asdescribedinSec- tionV(b).)Theirlowestself-res

29、onantfrequency canalsobe measureddirectly.Itisdesirablein mostinstancesthatthisself-resonantfrequency beconsiderablyhigherthanthehighestfrequency tobetransmittedthroughtheVideoamplifier. Ifcarrierdifferencetypeofsoundisde- sired,thecircuitshowninFigure4maybeuseful. Thisutilizesseries-shunttypeofpeak

30、ingwithan inductivelycoupled4.5megacycletrapforsound takeoff.The4.5megacycletrapcircuitshould beresonatedbymeansoftheModel 59.Thefm discriminatorshouldbealignedby meansofa sweepgeneratorwiththe59servingasatrace *TermansRadioEngineersHandbook,Page420-2, FinksPrinciplesofTelevisionEngineering,page227-

31、8. 8. marker.Thiscan be accomplished bymerelycoup- linginthe59tosecureabeatnotesuperimposed ontheoscilloscopetraceasshowninFigure5. Ifa sweepgeneratorisnot,available,the59can be used byfixingthecouplingtoL2andL3ata satisfactoryvaluetopermittakingad.c.dis- criminatorcharacteristicwiththeaidofa high r

32、esistanced.c.voltmeter(suchasorModel62). Thesecondary ofthdiscriminatorshould be tuned forcrossoverat4.5megacycles, whilethepri-, maryshouldbetunedforsymmetry ofthepositive andnegativepeaks.Ifnecessary,thecoupling betweentheprimaryand secondary should bead- justedtoseparatethepeaks byatleast200kilo-

33、 cyclesormore. Figure4indicatestheuseofd.c.trans- missionwithnegativepolarityinputvideosignal aswouldbeobtainedfrom adetectorshownin Figure6.Theuseofthisarrangementhasseveral advantages:suchas,economy oftubessincehigh levelvideoofthecorrectpolarityisavailable forsyncclippingwithoutextratUbes,noextra

34、 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

35、 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 L3a

36、ndL2tosatur- atethesoundlimi- ter.Tooclose couplingwillspoil thevideotransient response. Figure4 -TELEVISIONVIDEOOUTPUTSTAGEARRANGEDFOR CARRIERDIFFERENCESOUNDOUTPUTDISCRIMINATOR videodetectorandthevideoamplifierstageas showninFigure6.*Thedesignofthisfilter involvesfirstadeterminationoftheinputand ou

37、tputcapacitanceswiththeModel 59(Section V(a);)thenacalculationoftheloadresist- ance fromthedesiredqandwidth. Anexaminationoftheequationsforthis filtershowsthattheresonantfrequencyofthe seriescoilinparallelwiththesumofthein- putandoutputcapacitancesshouldbetwicethe cutofffrequencyofthefilter.Thisrela

38、tion isquiteusefulinrememberingthedesignfor- mulaforlowpassfilters;forthUS,theproduct ofLandC(inductanceandcapacitance)arede- termined.Theotherrelationwithregardto impedancelevelisgiveninFigure6. Itisusuallynecessarytoaddabout5 mmfd.inputcapacitywhenuSingIN34typeVideo detectors,inordertosecureproper

39、operation ofthefilter.Thelowestself-resonantfre- quencyoftheseriescoilshouldbeatleastas highasthei.f.passbandinordertoobtain goodi.f.rejection.Iftheself-resonancedoes Networktoreduce markerwidthbynarrow- ingtransmissionband- widthofoscilloscope MOOEl ( Note:Adjustthe couplingof the/Iodel59 toL3for c

40、onvenient 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

41、 capacities,andfcisthecutofffrequency. TypicalvalueofttRtt=2700 ohms. Figure6 -VIDEODETECTORLOWPASSFILTER occur,atthe1.f.frequency, arejectionpeakwill occuratthisfrequency.Thistypeoffilterthen resemblesthem-derivedtyperatherthanthe simpleconstant-kasshowninFigure6. Thevideodetectorispolarizedfornega

42、- tiveoutputinordertooperateproperlywiththe singlevideostageshowninFigure4.Obviously thedetectorpolaritydoesnotaffecttheopera- tionofthefilter,however. c.VideoI.F.BandpassAmplifierDesign ancAlignment : (1)Staggertuned(singletunedcircuit) amplifierscanbeverysuccessfullyusedfortele- visioni.f.s;howeve

43、r,ithasbeenpointedoutby Wallman* andothersthatthedistributonofstag- geredfrequenciesandcorrectloadingforeach circuitcanbestbecalculatedbyattentionto minimumphasenon-linearity.Afterthecorrect frequencieshave beendetermined,eachtuned.cir- cuitcan beeasilyadjustedby means oftheModel 59; theftthecorrect

44、loadresistorscan beplaced acrosseachcircuitandtheresultantcombination checkedforuniformityofamplituderesponseby meansofa sweepgeneratorandtheModel59asthe sweepmarker.Somesacrificeinstagegainresults fromtheuse ofstaggertunedcircuits.Ahopeless phasecharacteristicwillresult,ifchoiceof staggeredfrequenc

45、iesandloadingisbasedonlyon observationoftheresultantamplituderesponse. (2)Staggertunedamplifierscanalsobe madebyalternatingsingleand doubletunedcir- cuitswithproperchoiceofloadand peaksepara- tion.*Againthelocationofresonantfrequencies can be determined bytheModel59, andthesepara- tionofthedoubletun

46、edpeaks can beadjustedby a temporaryreductioninloadingformoreaccurate indicationontheModel 59. (3) Doubletunedcircuitamplifiers!canbe adjustedbyfirstloadingdownone ofthecircuits andsettingtheunloadedcircuittoapproximately thecorrectcenterfrequency;thenloadingitand removingtheloadfromtheothercircuitt

47、opermit settingittothecorrectcenterfrequencyalso. Thenbothloadscan beappliedandthecouplingin- creased,ifnecessarytosecureproperbandwith. Thelocationandseparationbetween peaks canbe alsomeasuredwiththe59.Afterloadingand *Wallman,H.,StaggerTuned1.F.Amplifiers,RadiationLaboratoryReport#524,February,194

48、4. 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-CoupledIntermediateFr

49、equencyAmplifiers,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.