Ampex-401-tape-sm维修电路原理图.pdf

1,MODEL401MAGNETICmaRECOISDEHHOLLYWOOD&VINEP0BOXZastHOLLYWOOD28CALIFDKPTTO:rCRS.SOcpLacbaOOttEECTRONftIIRadioFans.CN 收音机爱 好者资料库MODEL401The Model401isidenticaltotheMade-I400ineveryrespectexcepttheheada-s-sembly.The401incorporate-s-headsto-eraseandre-cordover-thefullwidthofthetape.Thustapesrecordedonthe401canbeplayedbackontheModel300andModel201withoutpreerasingtheunusedportionofthetapeandwithoutnecessitatinglevel adjustment.TheInstallation&OperationManualoftheModel400whichfollowsappliesinallrespectsotherthanthe halftrackrecordfeatures.Boththe400and401willplaybackeitherfullorhalftrackrecordingsrecordedonanyAMPEXrecorder.RadioFans.CN 收音机爱 好者资料库ISSUENUMBER3EFFECTIVESERIAL#2722AMPEXMODEL400INSTALLATION&OPERATIONMANUAL-IndexofSECTIONS,CIRCUITSANDDRAWINGSSECTIONISPECIFICATIONSSECTION11INSTALLATIONSECTIONUIOPERATIONSECTIONIVHEADASSEMBLYANDSPECIALPRECAUTIONSINUSESECTIONVELECTRONICALIGNMENTSECTIONVIMAINTENANCESECTIONVIIPARTSLISTS4NDSTOCKNUMBERSFIGURE1ELECTRONICSCHEMATICDIAGRAMFIGURE2POWERSUPPLYSCHEMATICDIAGRAMFIGURE3CONTROLCIRCUITSFIGURE4CONNECTIONDIAGRAMFORHIGHIMPEDANCEMICROPHONEFIGURE5CONNECTIONDIAGRAMFOR30AND50OHMMICROPHONESFIGURE6TOPPLATEFIGURE7ELECTRONICASSEMBLYFRONTPANELFIGURE8ELECTRONICASSEMBLYTOPVIEWFIGURE9MECHANICALLINKAGE3-12-51SPECIFICATIONS-MODEL400TapeSpeed.15inches persecondand7.5inches persecond,withmotorspeedchangeandequalizationswitchesconvenientlylocated.FrequencyResponseAt15inches+2db.50-15,000cyclesAt7i/ainches4-2db,70-10,000cycles+4db.30-15,000cyclesSignal-to-NoiseRatio.Over55db.atboth7l/Zinchespersecondand15inchespersecond,asdefinedbytheN. A. B.standards.Bydefinition,thesignal-to-noiseratioistheratioofpeakrecordinglevelto-thetotalunweightedplaybacknoisewhenerasingasignalofpeakrecordinglevelandintheabsenceofanewsignal.Thus,biasanderasenoiseareincluded,aswellasplaybackamplifier noise.Allfrequenciesbetween30and15,000cyclesare measured.Thepeakrecordinglevelis definedasthatlevelatwhich theoverallinputtooutputtotalr.m.s.harmonicdistortiondoesnotexceed3%whenmeasuredona400cycletone.StartingTime.Instantaneous.Whenstartingthetapeacceleratestofullspeedinlessthani/iosecondbecausecapstanmotoroperateswheneverpowerison.StoppingTime.Whenplayingatl5inches persecond,thetapemoveslessthan2inchesafterstopswitch isoperated.FlutterandWow,AtlSi.p.s.wellunder2/10%r.m,s,measuringallfluttercomponentsfrom0to300cyclesusingatoneof3,000cycles.At71/2inchespersecondunder 1/4%.PlaybackTimingAccuracy.2/10%.PlayingTime.32minutesat15inch speedwithstandardN. A. B.reel;64minutesat7.5inch speedoneachtrack.ThestandardR.M.A.reelmayalsobeused.TheModel400MagneticTapeRecorderis designedtorecordononlyone-halfofthestandard1/4widetapeinaccordancewithR.M.A,standards,Byturningthereelovekandrecordingontheotherhalf,twicetheamountofprogramcanbestoredonasinglereel,therebyeffectinga50%savingintape.RewindTime.OneandahalfminutesforthefullN,A.ree1Model4-jQSectionIPage1OperationSelector.Asingleselectorcontrolleverisused forFASTFORWARD,PLAY,STOP,andREWIND.Aseparaterecordbuttonenergizesrecordrelay,whichdropsout whenmachineisstopped.Shuttlingbackandforthoftapemadepossiblebychangingfromonemodeofoperationtotheother.CompletePlug-InHeadHousing,Erase,record,andplayback headsarecontainedinasingleplug-inheadhousing.SimultaneousMonitoring,Separaterecordandplaybackamplihersandheadsallowthetapetobemonitoredwhilerecording.Input.Aswitch allowstherecordertoaccommodateeithermicrophonelevellowimpedanceinputortobridge600ohmsplus4VUlinebalancedorunbalanced.PlaybackAmplifier.Plus4VUoutputinto600ohmsbalancedorunbalanced.Metering.A4inchVUmeterismountedonthefrontpanelandprovidesfor:a.Directmonitorofrecordinputsignalbeforeorduringrecording.b.Monitorofrecordedoutputsignalfromplaybackheadwhilerecordingorduringplayback.c,Readingbiascurrent.d.Readingerasecurrent.PhoneMonitoring.Aphonemonitorjack isprovidedfordirectmonitorofrecordinputsignalbeforeorduringrecording,andmonitorofrecordedoutputsignalfromplaybackheadwhilerecordingorduringplayback.AnA-Bswitchisincorporatedinorderthatdirectcomparisoncanbemadebetweentheoriginalprogramandtherecordedprogramwhilearecordingisbeingmade.ThesameswitchtransferstheVUmeterforlevelcomparisonandmonitoring.Mountings.Rackorportablecase,Dimen sions.Mechanicalunitismountedon153/4panelforstandardrackmounting.Electronicunitismountedon7panelforstandardrackmounting.Powersupplyisona51/4 panelforrackmounting,ormountedintheportablecase,PortablecaseholdingboththemechanicalModel400SectionIPage24-11-51unitandtheelectronicassemblyhasoveralldimensionsohapproximately133/4high,171/2deep,and20wide.Weight.Approximately75poundsforcompleteunitinportablecase.Model400SectionIPage34-11-51INSTALLATIONIMPORTANT:Beforeattemptingtooperatetherecorder,firstreadthefollowingsectionsoninstallationandoperation.Theportablemachineisshippedinaready-to-operatecondition.Therackmountedmachineshouldbemountedonastandard19relayrackwiththemechanicalunitabovethemainelectronicpanel.Theelectronicpowersupply panelshouldbemounteddirectlyabovethemechanicalassembly,oratleast5below theelectronicassembly.Greaterproximitytotheelectronicassemblywillresultinincreasedhumlevel.Forfurtherinformationonrackmounting,seePage3ofthissection,Allconnectionsarereadilyaccessiblefromthefrontpanel.Releasethefrontpanelcoverby unlatchingandremovingthe topcover.ThenumberssetoffinparenthesesinthefollowingtextrefertothenumbereddesignationsinFig.6andFig.7.I.OUTPUT:A.ForStudioLine:Plus4VU,600ohmlineoutput,balancedorunbalanced,isavailableacrossterminals2and3of theLINEOUTconnector,12.Pin1isthechassisground.Ifunbalancedoutputisdesired,tieeithersideofthelinetoground.Itisnecessarytosupply600ohmterminationtothisoutputaalltimesinordertomaintaincorrectmetercalibrationwhilerecordingor playingback.Therefore,iftheoutputisnot feedingaterminatedlineorif theoutputisnotconnected,suchasonremotepickups,theLINEOUTPUTTERMINATIONswitch,13,mustbeswitchedtoIN.B.ForConnectiontoHighImpedanceAmplifierInput:Connectpin3oftheLINEOUTconnector,12,tothehighsideoftheamplifierinput.Strappins1and2oftheconnectorandconnecttothegroundsideof theamplifierinput.The LINEOUTPUTTERMINATIONswitch,15,mustbeleftinthepositiondesignatedINatalltimes,asexplainedinAabove.Model400SectionIIPage13-26-51II.INPUT:Thefollowing inputsareprovided:A.Microphones:Anylowimpedancemicrophone,thenominal impedanceofwhichisintherangeof30to250ohmscanbepluggedindirectly.Connectmicrophonetopins2and3oftheinputconnection,14.Connect cableshieldtopin1.PlacetheINPUTTRANSFERSWITCH,15,intheMICposition.Themicrophoneinputtransformerisstrappedfortheoptimumstepupfora150to250ohmsource.Therefore,inthecaseofmicrophoneshaving50ohmsorlessimpedance,6db.additionalgaincanbeobtainedbystrappingtheinputasshowninFig.5.Thisisnotusuallynecessary,however,andshouldnotbedoneunlessinsufficientgainisfoundto exist.Iftheinputisre-strapped,seriousfrequencydiscriminationwillexistshouldtheinputbefedfromasourceimpedancegreaterthan50ohms.Highimpedancemicrophonesarenotrecommendedforuseonthisequipment.Ingeneral,thequalityobtainablefromhighimpedancemicrophonesisnotsatisfactoryforprofessionalwork.Intheeventthatitbecomesnecessarytoconnectahighimpedancemicrophone,theinputcircuitwillhavetobere-wiredasshowninFig.4.B.BridgingaBalancedStudioLine:Connectbalancedlinetopins2and3oftheinputconnector,14.Pin1isground.PlacetheINPUTTRANSFERSWITCH,15,intheSALBRIDGEEdsition.Inputlevelsofminus10toplus10VUcanbeaccommodated.Theloadplacedonthe lineis approximately100,000ohms.If theinputtransformerisrestrappedfor50ohms,theinputlevelaccommodatedonthebalancedbridgepositionisminus16toplus4VU.Forbridginghigherorlowerlevellines,anexternalbridgecanbewiredinthe linetothemachine.Thiswouldconsistof aresistance,thevalueofwhichshouldbe50,000timesti.RMSprogramvoltage,inserieswitheachsideoftheline,A 50ohmresistorshouldterminatetheoutputsideofthetwobridgingrest.tors.Theoutputofthebridgemustbefedtothemicrophoneinputftherecorder.C.BridginganUnbalancedSourceConnectunbalancedline,radiotu:.r,etc.,topins3and1ofModel400SectionIIPage2theinputconnector14.Pinusthegroundside.PlacetheINPUTTRANSFERSWITCH,15,intheUNBAL.BRIDGEposition.Thisconnection,rovides100,000ohmsbridgingofanyRMSprogramvoltagegrcaterthani/avolt.III.PHONES:Anysensitivehighimpedanceheadphonescanbepluggedinthejack11,providedformonitoringofincominglineorplaybackoftherecording.IV,RECOMMENDEDRACK MOUNTINGOFTWOMACHINES:Iftwo400sor4Olsaretobemountedonastandardrack,thefollowingplacementisrecommendedstartingatthetopof therack:1.Installa13/4inchspacerpanelatthe topof therack.2.InstallbelowthispaneltheMechanicalAssemblyformachine#1.3.InstalltheElectronicAssemblyformachine#1.4.Installa13/4inchor3i/ainchspacerpanel.5.InstalltheMechanicalAssembly#2.6,InstalltheElectronicAssembly#2.7.Installa51/4inchor7inchspacerpanel.S.Installbothpowersupplypanelsatthebottom.Thecableonthepowersupplyfortheupper.recorderwillhavetobe:vtendcdinlength.Itisimportantthatnopowersupplybecloserthan5inchestoanElectronicAssembly!Model400SectionIIPage33-26-SiOPERATION-MODEL400I.REEL SIZE:TheturntableontheleftsidetapesupplyisequippedtohandleeithertheN. A.B.10u/areeloftape orthesmallerR.iv!.A.5and7inchsizes.Handlingthesedifferenttypereelsonthisturntablecanbeaccomplishedas follows:1N, A.B.-10i/aReel-PlacetheReelSizeSwitch6intheLargepositionandplacethereelontheturntableafterpositioningtheblackplasticreelcenteringguidethathas beenprovided.2R.M.A.-7 &5Reels-PlacetheReelSizeSwitch6intheSmallpositionandplacethereelonthekeyedturntabledirectly.TheturntableontherightsidetakeupreelwillhandleonlytheN. A.B.101/2reelandthe keyshavenotbeenprovidedontheturntabletodrivethesmallreels.AttemptingtousethesmallR.M.A.reelsontherighthandtakeupturntablewillseriouslyimpairtheperformanceof themachine.II.TAPETHREADING:Threadtape asindicatedinFig.6.Thetakeuptensionarm,5,mustbemovedintopositionasshown,inordertosupplypowertooperatethemachine.III.POWER:Powerissuppliedtothetopplatethroughswitch,3,whichmustbeturnedontoenergizethemotors,Mainpowerissuppliedthroughswitch,9,whichmustbeturnedontooperatetheelectronicsandtopplate.Thetopplateandelectronicsareindividuallyfusedby7and8,respectively.IV.FUSES:TopPlateFuse72AmperesChassisFuse81AmpereV.SPEEDSWITCHES:Therearetwoswitchesassociatedwithoperatingspeed.Switch4governsthemotor,and19correctsequalizationintheamplifiers.VI.TAPEMOTION:Thetapemotioniscontrolledbymeansofamodeselectorswitch1andthePLAYbuUei2,directlytoitsleft.Theselectorswitch shouldbemovedfirmlybymeansof theselectorknobattached,Hold the knobsecurelybetweenthethumb andforefingerwhilechangingitsposition.Rapid,positivemotionof theselectorknobisrecommendedinpreferencetoslowaction,Thisistoinsuresimultaneousactionofallnecessaryfunctions.Model400SectionIIIPage13-12-51-IMPORTANT-Thetripoutswitchwillnotdisengagethecapstan idlerattheendofthereelunlessthetapewillfreelydisengagethereelhub.Allnewfactorywoundreelsoftapeshouldbeunwoundandinspected,astheyareusuallyloopedtothehubinamannersuchthattheywiiinotcomefree.Ifthetapedoes notdisengagethereel,thedrivecapstanwillwearaflatintherubbercapstan idlerwheelwhichwillnecessitatethewheelsreplacement.Anyadhesivematerialaccumulationonthehubmustberemovedwithsolventforthesamereason,1.PlayandRecord,ThetapeissetintoplaymotionbyfirstdepressingthePLAYbutton,2,and thenmovingtheselectorswitch,1,totheFORWARDposition.Itis importantthatthePLAYbuttonbedepressedbeforemovingtheselectorswitchorthetapewillmoveatthefast forwardspee;dinsteadofattheoperatingspeed.Thetapemustbecompletelystoppedbeforestartinginthismode.Theselectorswitchshouldbemovedfirmlyandrapidlytoinsureproperoperation.2,Stop.Tostopthetapemotion,whileitismovinginanymode,merelyreturntheselectorswitch,1,totheOFFposition,Thiswilloccurautomaticallyifthetapeshouldbreakorrunoffofeitherreel,CAUTION:Neverstopthemachineneartheendof afastwindwhenusingthesmallreel,butallowthetapetorunoff,Whentheamountoftaperemainingontheunwindingreelislessthan1/2;therateofrotationofthereelbecomessogreatthatitmaynotstopwithoutthrowingaslackloop.3,FastForward,Movetheselectorswitch,1,towardtheleftwithoutdepressingthebutton,Thisisafa?t forwardspeedwhichisusedinordertorapidlyarriveatapoint withinthereel,4,Rewind,Movetheselectorswitch,1,towardtheright.Thisisafastreverseandisusedtorewindthetape completelyortoreturntoanearliersectior,usingeitherthefastforwardorrewindmode,itis desirabletoremovethetapefromdirectcontactwiththeheadsbyopeningthegateoftheheadassembly,Thisistopreventoxidecoatingfromdepositingontheheadsandimpairingtheperformance,andreduceswearontheheads,Inputtingtherecorderintoplayorfast forwardimmediatelyafterfastrewind,slackinthetapemay occLrcausingtherecordertotripoff,Inthiscase,returnthemode.electortooff,takeuptheslackinthetape,andthemachinewillfunctionnormally.TheconditionisbroughtaboutbytheturntablemotorspinningfreeforashorttimeinModel400SectionIIIPage24-11-51thedirentinnitwaslastrimning.Theoperatorwillfindanumberofwaystoavnisid.eiay.dnetothiscondition.Oneofthesimplestjstomovethemodeselectorafewdegreesinthedirectionthemachinewaslastrunningbefore,proceedinginthedesiredmode.VII.PLAYBACK:Toplaybackapreviouslyrecordedtape,turntheMST.ERand OUTPUTswitc.h,20,totheextremeleftpositiondesignatedPL&Y.BAilIC.ThenstartthetapeinmotionasindicatedunderPlay.Iftherecordingwasmadeatthecorrectlevel,theVUMeterwillpeakonozero.Noattemptshouldbemade toalterthegainoftheplaybackamplifierifthemeterdoesnotpeakon0zero.Otherwise,thecalibrationafthismeterasarecordlevelindicatorwillbedestroyed.TheplaybackgainwillbeclosewhenplayinganytaperecordedtoN.A.B.specificationsatl5?/sec.VIII,RECORD:Torecordanewprogramonpreviouslyrecordedtape,oronblanktape,turnswitch20tothesecondpositionfromtheleftwhichisdesignatedRECORD-LEVEL.TurntheRecordGaincontrol,16,clockwiseuntilthelevelreads0zeroontheVUmeteronthemostintenseprogrampeaks.Theprogramcanbeaudiblymonitoredthrougheithertheearphonesjack,io,ortheLINEOUTbeforethetapeisinmotion,Forcorrectmetercalibrationitis importantthattheLINEOUTbeproperlyterminatedeitherexternaltothemachineorbyuseoftheLINEOUTPUTTERMINATIONswitch,13.See detailedinstructionsunderINSTALLATION.Thisdirectmonitorfeatureallowstheprogramtobesetupthroughthemachinewithoutactuallyrecordingduringthesetupperiod.Whentheprogramlevelisproperlyset,startthetape inmotionasindicatedunderPLAY.ThenpushtheRECORDbutton,18.Besurethereisadelayofatleasti/asecondbefore operatingtheRECORDbutton,asthesurgefromoperatingthePLAYcontrolmaymagnetizetherecordhead,thereby increasingthenoiselevelonthetape.Therecordindicator917,abovetherecordbutton willnowglowandthemachineisrecording.Itis desirabletobhecktherecordbiasanderasecurrentsoccasionally.Inordertodothis,repositionswitch,20,tothepositionsdesignatedBIASandERASE,respectively,Theeraseisnotcriticalandshouldreadintheupperhalfofthemeterscale,Thebiasonthismachine,serial#2701andafter,shouldreadbetween-1/2andFl/aontheVUscale,Thebiasissomewhatcriticalandmustbekept withintheindicatedrangeinordertorecordthehigherfrequenciesat71/?inchtapespeed.Thebiasisadjustedbymeansofthelockedcontrol,11.Themetercalibrationforbiasmeasureme:itcanbecheckedasindicatedinelectronicalignment.Anactual comparisonoftherecordingwiththedirectprogramModel400SectionIllPage32-16-51canbemadebotha