SCR-614A_BC-969A_RA-61A_serv_user_TM11-873_1943.pdf

i= (WAR DEPARTMENTTIUI11 Q1Q f s TECHNICALMANUAL1IIIII UIJ 13 iUS.rjse ,-v iML 6 RADIOSET SCR-614-A RADIORECEIVERBC-969-APOWERSUPPLYUNITRA-61-A Dissemination of resfjficledmatter. The information contained in restricteddocumentsand the essentialcharacteristicsofrestricted materielmaybegiventoanypersonknownto be in the serviceof theUnitedStatesand to persons ofundoubted loyaltyand discre tionwhoarecooperatinginGovernmentwork,but willnotbe communicatedto thepublicor to the press exceptby authorized militarypublicrelationsagencies. (See alsopar.I8fc.AR380-5, 28Sepl942.) IFARDEPARTMENT 12NOVEMBER194: Generated on 2015-10-01 04:36 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google WARDEPARTMENTTECHNICALMANUAL TM11-873RESTRICTED RADIO SETSCR-614-A RADIORECEIVERBC-969-A POWERSUPPLYUNITRA-61-A Thisdocumentcontains informationaffectingthenationaldefenseof the UnitedStateswithinthe meaningoftheEspionage Act, 50U.S.C., 31and32,as amended.Itstransmissionor therevelationofitscontents in anymannerto anunauthorizedperson isprohibited bylaw. Dissemination of restricted matte*,The information contained inre stricteddocumentsand the essentialcharacteristicsof restricted materiel maybe giventoanypersonknownto be in the serviceof theUnited Statesandtopersonsofundoubted loyaltyanddiscretionwhoare cooperatinginGovernment work,butwillnotbecommunicatedto the publicortothepressexceptby authorized militarypublicrelations agencies. (See also par.186.AR380-5,28Sep 1942.) WARDEPARTMENT12NOVEMBER1943 i Generated on 2015-10-01 04:36 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google WARDEPARTMENT WASHINGTON 25.D. C, 12November1943. TM11-873,RadioSetSCR-614-A,ispublishedfortheinformation and guidanceofallconcerned. A. G.062.11 (5-11-43). Byorderofthe SecretaryofWar: G. C.MARSHALL. Chief of Staff. * Official: J. A.ULIO, MajorGereral, TheAdjutantGeneral. Distribution:X (For explanationof symbolsseeFM 21-6.) Generated on 2015-10-01 04:36 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google TABLEOF CONTENTS SECTION I. DESCRIPTION -T/V (/ Paragraphtz(f,jPage 1.General. V *.I 2.Maincomponents,weights,and dimensions. I 3.Radio Receiver BC-969-A.2 4.CaseCS-109-A. 6 5.MountingFT-4!1-A.6 6.Power SupplyUnitRA-61-A.6 II.INSTALLATIONANDOPERATION 7.Unpacking.10 8.Installationin vehicles. .10 9.Installationin fixed locations.II 10.InstallationinRadio Direction Finder Central TC-8andRadio Intercept CentralTC-9.1 1 1 1.PreparationofRadioSetSCR-614-Afor operation.11 12.Operation. .14 III.FUNCTIONINGOF PARTS 13.General circuit.17 )4. Antenna circuit. 17 15.Radiofrequencyamplifier.18 16.Highfrequencyoscillator.19 17.Converter.20 18.First i-fStage.21 19.Secondi-fStage.22 20.Audiodetector.22 21.Noise limiter.23 22.Audiofrequencyamplifier. 23 - M574749 .-* Generated on 2015-10-01 04:36 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google TABLEOF CONTENTS (Continued) ParagraphPage 23.Automaticvolumecontrol24 24.Beat oscillator25 25.Auxiliarydiodecircuit25 26.Tuning indicator26 27.Voltage regulator26 28.Voltage supply26 29.Power SupplyUnit RA-61-A26 IV. MAINTENANCE 30.Operationalcheck in field28 31.Fieldupkeep29 32.Trouble.locationand remedychart34 33.Alignmentprocedure36 34.Disassemblyandreassemblyof frontpanel dialassembly40 35.Replacement of crystal filter, switchand socket42 36.Replacement offixed capacitors43 37.Replacementof bandswitchandlimiter switch43 38.Replacementof transformers45 39.Replacement ofthe gangcapacitor46 40.Replacementof tube sockets47 41.Servicing Power SupplyUnit RA-61-A47 42.Performancecharacteristics50 43.Moistureproofing51 V.SUPPLEMENTARYDATA 44.Tabular list ofreplaceableparts54 45.Index ofmanufacturers 94 rv Generated on 2015-10-01 04:36 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google LISTOFILLUSTRATIONS Fig. No.TitlePage 1.RadioSetSCR-614-AVIII 2.Radio ReceiverBC-969-A,backview3 3.Radio Receiver BC-969-A inCaseCS-I09-AonMounting FT-411-A,frontview5 4.Power SupplyUnit RA-61-AonMountingFT-414, diagonalview7 5.Power SupplyUnit RA-61-AonMounting FT-414,backview9 6.Power SupplyUnitRA-61-A,schematiccircuitdiagram.27 7.RadioReceiverBC-969-A,tubesocketsandtransformers resistancediagram,bottomviewofchassis32 8.RadioReceiver BC-969-A, tubesocketvoltagediagram, bottomviewofchassis33 9.Radio ReceiverBC-969-A,topview37 10.Power SupplyUnit RA-61-A, interiorview48 11.Power SupplyUnit, RA-61-A,practical wiring diagram.49 12.Radio ReceiverBC-969-A,schematiccircuitdiagram97 13.Radio Receiver BC-969-A,simplifiedschematiccircuit diagram99 Auxiliarydiodecircuit Automaticvolumecontrol circuit 14.RadioReceiver BC-969-A,bottomplateremoved,bottom view101 15.Radio Receiver BC-969-A,practical wiring diagram103 Generated on 2015-10-01 04:36 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google DESTRUCTIONNOTICE WHYTopreventthe enemyfromusing or salvagingthisequipment for his benefit. WHENWhenorderedby yourcommander,or when you are in imme diatedanger of capture. HOW-I.Removechassisfromcase by looseningthe eightknurled screws aroundthefrontedges and then: 2.SmashUse sledges,axes, hand-axes,pick-axes,hammers, crowbars, heavy tools,etc. 3.CutUseaxes,hand-axes,machete,etc. 4.BurnUsegasoline, kerosene,oil,flame-throwers, incen diarygrenades, etc. 5.ExplosivesUse firearms,grenades,TNT,etc. 6.DisposalBuryinslittrenches,fox-holes,otherholes. Throwin streams.Scatter. 7.USEANYTHING AVAILABLEFOR DESTRUCTION OFTHIS EQUIPMENT. WHATI.SmashTransformers,oscillator coils,tubes, capacitors, potentiometers,chokes. (If thereistime,firstremovethe shield cansfromtheseunits byremovingthe twotop nuts thendirectlysmashthe componentsandcutthe wires.) 2.CutIfthereistime, remove thebottomplatefromchassis byremovingthe ten screwsaroundthebottomedges and cut wiringandripoutresistors,capacitors andpoten tiometers. 3.BurnThistechnicalmanual. 4.Buryorscatter Any or all oftheabovepiecesafter breaking. DESTROYEVERYTHING VI Generated on 2015-10-01 04:37 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google SAFETYNOTICE THEHIGHVOLTAGEOUTPUTOF POWERSUPPLY UNIT RA-61-AIS250 VOLTS,APPEARINGACROSSTERMINALS 8AAND8F.THIS250VOLTSISAPPLIEDTOTHETUBE PLATESANDOTHER POINTSONRADIO RECEIVERBC-969-A THROUGHTHE POWER SWITCH,76,ACROSSTERMINALS FAND A.THE VOLTAGE ACROSSTERMINALSC AND DALSO ISDANGEROUSLYHIGH.DONTTOUCHTHESEHIGH VOLTAGES!THESHOCKMIGHTKILLYOU. VII Generated on 2015-10-01 04:37 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google 19 r* CO Q O 9 8 Figure1.RadioSetSCR-614-A,frontview. VIII Generated on 2015-10-01 04:37 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google TM11-873Pars1-2 RESTRICTED ThismanualsupersedesTM11-873,dated31August1943and28October1943. SECTIONI DESCRIPTION Paragraph General1 Maincomponents,weights,and dimensions2 Radio Receiver BC-969-A 3 CaseCS-I09-A4 MountingFT-411-A5 Power SupplyUnit RA-61-A 6 1.General.RadioSetSCR-614-Aisalowfrequencycommunica tionset usedfor interceptpurposes.Itcoversthefrequencyrangeof 15-150kilocyclesandreceivesc-wandamplitudemodulatedtoneand voice signals.Ithasapoweroutputof twowatts.RadioSetSCR-6I4-A consistsmainlyofRadio Receiver BC-969-Ain CaseCS-109-A installed onMountingFT-411-A(figure 1). Neitherthe case normountingis used when the receiver is placedinarack;the case may be usedwithout themountingwhen the receiveris set onatable;themountingmust be used in vehicles.Powerisfurnished by Power SupplyUnit RA-61-Aon mounting FT-414(figure 1) installednear the receiver.The mounting neednotbe used whenthe powersupply unitis mountedonarackor placed onatable.The overallsize of the receiver in the case and on the mountingis 2P/4 inches long, 12/4 inches high,and l?1 inchesdeep; theweightis78.1pounds.The overallsize of the poweruniton the mountingis.19incheslong, 55/gincheshigh,and14inchesdeep;the weight(including Cords CD-872and CD-873) is 63.7 pounds. 2.MAINCOMPONENTS, WEIGHTS,ANDDIMENSIONS. DimensionsSig.C Article (ininches) WeightStock widthheightdepth(pounds) Number Radio Receiver BC-969-A19x10y2x 15% 40.3 CaseCS-I09-A 20% x IO/2 * 13/2 18.5 MountingFT-411-A 2l/4 x 3/2 x 13/2 10.2 Power SupplyUnit RA-61-A.19x4x 13% 52.1 MountingFT-414 !8/4 x 3/2 *1 1%9.5 Cord CD-872length7feet1.5 Cord CD-873length 10feet0.6 I Generated on 2015-10-01 04:37 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google Par3RADIO SETSCR-614-ATM11-873 3.RADIO RECEIVERBC-969-A.Radio Receiver BC-969-Ais a 12-tube,superheterodynereceiver coveringthe frequency ranges ofI5-30 kilocyclesin bandI,30-67.5 kilocyclesin band2,and 67.5-150 kilocycles in band3.Thereceiverhasautomaticvolumecontrol, anoiselimiter, acrystalfilter,abeat oscillator,andan electronray tuning indicator. Ithas anilluminated dial calibratedinkilocycles withamaskcontrolled by the FREQ. BANDswitch,showingonlythe range inuse.There ceiver filamentsoperate on12.6volts,1.95amperes,alternatingor direct current,and the platesupplyis 250volts,120milliamperes direct current. PowerisusuallysuppliedbyPower SupplyUnitRA-61-A,butmaybe supplied by Power Supply Unit PE-223or by batteries. a.Inputconnections.Allinputconnectionsto the receiverare at the back of the chassis.Theyare: N (1) ANTENNA100ohm. Thisconnectionis marked100ohm underANTENNA(figure 2). PlugPL-284isconnectedtoSocket SO-264,through AdapterPL-293.Thisconnectionisnormallyfora balancedtransmissionlinebutyou can,ifnecessary, useit witheither side of theinputgroundedto the chassis. Theantennashouldbe aslong aspossiblein orderto balancetheline forthe best results.Theproper antennawouldbe9300 feet long,ornearlytwo miles,butthe receiver willoperatewithamuchshorter antenna; in fact,good receptionis possiblewithlessthan100feet of antennaeven on the100ohminput, (2) ANTENNAWHIP.Thisconnectionisfora30-footwhip antenna.Plug PL-259is connectedto Socket SO-239,through Adapter M-359.The sensitivityofthe receiverislowerusingthis connection, souseitwhenonlyashortantennaisavailable. (3) Power inputreceptacle.Thisisthe large unmarkedsocket with6pins.Theplug onCord CD-872fromthe powersupply unitcon nectsto thisreceptacle.Thereareterminalpinsforalltherequired filamentand platesupplyconnections. b.Outputconnections. There isonlyoneoutputconnectionon thefrontpanel;the rest are at the back of the chassis. (1) Headsetjack. ThisjackmarkedOUTPUTonthefront panelisforaheadset having 250ohms impedance,suchasHeadsetHS-30. (2)AUXILIARY DIODE.Thereare three screwterminalson the panel markedAUXILIARYDIODE.Thecenterterminalis marked GROUND(groundedto chassis),theothersaremarked (negative) and+(positive).Theseterminalsare used to connect an externald-c meter,or an oscilloscopefor alignmentpurposesorfor observationof themodulationenvelope. (3) OUTPUTterminalpanel.Thispanelhasfivescrewtype terminalshavingthefollowing outputimpedances asmarked: (a) 250OHMStoGROUND (b) 250OHMSbalancedto ground (c) 4000OHMStoGROUND Generated on 2015-10-01 04:37 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google DESCRIPTION Par3 TM11-873 Figure2. Radio Receiver BC-969-A, backview Generated on 2015-10-01 04:37 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google Par3RADIO SETSCR-714-ATM11-873 These terminalsare used to connectaspeaker or headsethavingasimilar impedance.TheOUTPUTjackon thefrontpanelisconnectedtothe 250OHMStoGROUNDterminals. c.Operating controls.Themaincontrols for operatingthere ceiver are on thefrontpanel (figure 3). 1I) TUNINGknob. TheTUNINGknobhasaratioof 36 to one. Itturns18timesin coveringthe range of each of the three frequency bands. (2)FREQ. BANDknob. Thiscontrolselectsthe desiredfre quencyband. (3) LIMITERknob. This knob controlsthe noiselimitercir cuit.AtOFFthelimiterisnot working.Positions 1, 2,and3give increasinglymorelimitingof noise. (4) AUDIO GAINcontrol.Thisknob controlsthevolumeof the receiver. (5) AUDIO TONEcontrol.As this knobisturnedto theright (clockwise),the higheraudiofrequenciesarecutoff.Itis also used to decrease the effect of certaintypes of interference. (6) CRYSTALSELECTIVITYcontrol.Thisknob controlsa switch havingthree positions.WhenthepointerisatOUT,thecrystal filter isnt working.Positions1and2givetwodegrees ofcrystal selec tivity.The crystal filteris used tofilter outchannelsclose to the one being received;hence,itis especially usefulin receivingCW. (7) BEATOSC.PITCHknob. This control adjuststhepitch of the beatoscillatoroverarange of5000cycles either sideofthe center position. (8) POWER ON-OFFswitch.Thisswitch controlsthe a-cinput to the powersupply unit through Cord CD-872;itturnsthe powerto the receiver on and off. (9) BEATOSC.ON-OFFswitch.Thisswitch turnsthebeat oscillatoron and off. (10) WHIP-100Ohmantennaswitch.(SeeFigure 2.) This switch (on backof chassis) changes the antennaconnectionsasmarked, dependingon thetypeof antennayouare using.When throwndown ward toward100Ohmthewhipantennaisgrounded.When thrownup ward towardWHIP,thewhipantennaisconnectedto the propercircuit. (11) ANT.TRIMMER.Thistrimmercouples thewhipantenna andis seldomadjusted.Itisadjustedandlockedinpositionas the receiverisissued and mustnotbe changedexcept in special cases*. (12) HI-LOWoutputpowercontrol.This switchis ontopof the chassis(figure 9). Youcan reachit by liftingthelidof the receiver Antennashavingacapacitancegreaterthan200micromicrofaradsrequire slightread justmenttoimprovetheantenna circuittuning.However,this detunes the100ohm input circuitso isseldom desirable. Generated on 2015-10-01 04:37 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google TM11-873Par3DESCRIPTION oo Figure3.RadioReceiverBC-969-AinCaseCS-109-A on MountingFT-411-A,frontview Generated on 2015-10-01 04:37 GMT / Public Domain, Google-digitized / http:/www.hathitrust.org/access_use#pd-google Pars3-4-5-6RADIO SETSCR-614-ATM11-873 case.The switchiskept onHIexcept whenatelephone lineisconnected to thereceiver;thentheLOWpositionisusedsothatthe linecannot beoverloadediftheAUDIO GAINcontrolisturnedup too far. d.Vacuum tubes.Radio Receiver BC-969-Ausestwelvetubes whichare shippedinstalledin theirsocketsexceptforthetuningindi catortube.Also,thereis akit containingone spare tube for each socket. Thetubes used are: CommercialSig.C. NumberNumber (VO R-Famplifier12SK7VT-131 (V.) Converter12SA7VT-I61 (V3) H-Foscillator