O o O o o o O o c o o o o a, A30A57-GPIB Interface | Tektronix 494A

A30-POWER St,PPLY

A30A57-GPIB INTERFACE

A62-LOG &

VIOEOATPL

A61_DIGITAL STORAGEYERT

A6O-DIGITAL STORAGE }IORIZ

As8-PROCESSOR

456_GPIB

A5'-MEMORY

A26_AUXILARY SYNTHESIZER

A51_COUNTER

PHASE LOCK SYNTI{ESIZER

A/f0-SPAN ATTENUATOR

A/16-CENTER FREOCOilTROL

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Tektronix 494AP service manual O o O o o o O o c o o o o a, A30A57-GPIB Interface

Contents

Tektronix Page O o o o o o o o a o O o o o o o o o o Releaseof Copyright O o O o o o oO a a o o o O a o o A a a a a Warranty O o o o oO o A a a a A o a o o a o o 494A/494APServiceVot.1 O oA o A o o o o o o o O a o o o a oA o o 494A/494APservice Manuatis divided into two volumes O aO o o o o o o CONTENTSGonr O o o O a o o o O a o o o O o t A a o o o a o oO o a o o o O o o o o o O o a o A o o o o o Powersupply O o o o a oA o RAM VOLUME2 494A/94APServiceVot.1 O o o o O t494A/494APServlceVol Preselector P3035on theVideoProcessorboard Rejection A o O o O o o494A/494APServtceVot.1 Simplifiedschematicof harmonicmixer Basicblockdiagramof a -rNsynthesizer494A/494APServlceVot Simplifieddigital-to-analog Converter O a o O o oO o a o 944/494AP Service Vot SpEctFtcATloNsOptions 22 Waveguide MtxERSCHARACTERTSTTCS Do Not ServiceAlone O o o oO a o This Manual O a o o o A o o o o Sedon 1 4g4l494Ap Servlce,Vol O a O o O o o o SELValue. Mlxer 18to 26.5to 33 to 490U 40 to WM 49OVWM 490E 490W 10to 170GHz O o A o Electricalcharacteristics O o o o O o a o o o o A o o o a Freouencyrelatedcharacteristics +tAF. x BEF + 20 + 4NHz Characteristic Performance Uirement Normal Accuracyand Ldentical ResolutionResolution FrequencySpan/Div OverallRange MinimumSpan/Div KHz 300 Hz 30 Hz 3Hz Typically 30 psldivision of pulse tude Freouency Relatedcharacteristics E o oFreq O o a e O a o s33-s0GHz Accuracy Steps 10 dB/divLogMode Accuracy Normal or Delta Mode ReferenceLevel SEt With Data ENTRYpush ButtonsDisplayDynamicRange Accuracy RF Attenuatol Range Accuracy Dcto 1 GHz Delta a Mode provides differential Performancq RequirementDecadeTransitions 100 DBc C o A07-100Amplitude Inputsignalcharacteristics Externalmixer O a o e O o o a Speclfication- 494Al4g4ApService,Vol J104 ACCESSORy Pin4 Pin51stLO OUTPUTpower UalrbratorcAL ouT Outputsignalcharacteristics Teristics O a o o Line Speclfication- 494A1494APService,Vot.1 Temperature Operatingand HumidityCE03-15 kHzto 50 MHzpowerleads CS02-50 KHz to 400 MHz power F u l l l i m i t Leads O o o o o o o 15.05 28.85inches232x 392x 732.gmmSrDEvtEw O c o A a o o 494A1494ApService,Vot O a o o o o o a o o A o a o o oUnpackingand INITIALINSPECT6N Connectingpower PowerSourceand power RequirementsInstallation- 494A/494ApServlce,Vol O o o A o o o o o o o O o o o o o o O o o o o a o O o a o o o o o o O o a o o o O o o o o o o o O c o O a o o Secton 4g4Al494ApServiceVol O o o o o o o o o o o o o o o o o o o O o o o o o o o o o o o o o o o o O o o o o oEouipmentreouired O o o o o o o o o o o o o o o o o o o o Accuracy*0.2s dB ioLodB/soolttffi LrlrGtr Eouipment Reouired Preliminarypreparation MAX 10DB/ 2ODB PerformanceCheck procedure 4g4Ll4g4ApServiceVol O o o o o o o o o o o o Performancecheckprocedure O o a o o a o o o o o o o o o o o o o o o o o o o o aTrME/DrV O o o o a o o a o a o o o TIME/DIVAUTOSPAN/DIV TME/DV Auto Vertcaldtsplay O a o o o o o A a o o oA a o o o o o o o a o o o o o a o o o o o Center Freouencyaccuracycheckpoints O o a o a A a o o o o a o o o O o a o o o o o o a o CheckCenterFrequencyStabilitvAutoresoln on Verticaldtsplay Resolutionbandwidthauto O a o a o a o a aO o a o o o o o o a o o o o o a o o TME/DVAUTO SPAN/DrV TlmeMarkGeneratorMarkerOutput 50 Hz 20 ms O o a a o o o a o a o a a o o a o a o o o o O a o a oAutoresoln Reflevel 10dB/Dtv A o o o a o o A o a o o o aA a TimeAccuracy C.**qyegp WithinS%oftherateserecitJi CheckResolutionBandwidth and shape Factor O a a o a o aO a o O o a o A o Minnose Qlglptv to 50Hz, andVERlCnl.drdpr-ry O o a o a A o o o o o o o o o o O o o o o A o oSPAN/DV MIN RFATTENdB Nro sMAooaeten LowLosscoAxcABLEwrrx sul courEEroid0 GHz 7.4 GHz 9,4 c O o a o o A o O o a a aA o o o o o a A o a a a o a o o a O o o o Narrow Videofilter PEAK/AVERAGE O o a o o o A o TmeidivautoPart Narrowvideofilter TME/DV Auto PEAK/AVERAGE PerformanceCheckprocedure- 4g4Al4g4ApServlceVol.1 O o a Testsettings O a aTrME/DtV Vertical Display 21BIDIVNarrowvtdeofilter TIME/DIV Auto 15.RF attenuato. test equipment setup for 50-60 dB step O o O o a A a a o a o CentebfreouencyDisplay Widevideofilter O a a o o o o a o A o o o o o A o aDB/Dtv O o a O a a12s 103 Trr PerformanceCheck procedure- 4g4A/4g4ApServiceVol Resolutionbandwidth 100 kHzFreorange O a CheckLO Emission -70 dBmor tessAutoresoln Otsplay PerformanceCheckprocedure- 4g4Al4g4ApServiceVol.1 18.Test equipmentsetuplor checklngharmonicdistortion @o@o@g@@ EXT PerformanceCheckprocedure- 4g4A/4g4ApServiceVol. l ResoluttonBandwtdth 1 MHz Verticaldisplay LIN Triggering INT TIME/OIV Vertcal Dtsplay 2 dB/DtVTME/DV EXT Rrttl OptioninstrumentsI3fil l t r l CheckHORIZOUTPUTSignatLevel Spanidiv DtsplayMAX Hold Verttcal Tmeidiv Auto PEAK/AVERAGE Comb Generator Mooule Q15oit riline UllTR5O2 OutputLevel -dBm Var dB Dot Intensity Off A o o o c Gpibverificationprogram O o o o o o o a o ReturnReturn 5OOOREM49XPGPIBVERIFICATION Program 5O9OINPUTT$ O a o a o r 8070INPUT 8100PRINT9040PRTNT10OMSGEOS 1OO1OPRINTSELECTEDDEVICE-CLEAR...SDC A o o O c 16000REM Talkonlymode 16010PAGE16050PRTNTTALK Jtestng only 16060INPUT Onlymode Fail ANDRENREMorE JGPIBvERlFlcArtoH Cotapr-erEoJJLrsrEN!TALKTLF OCrnoiness Message O o o o o o o O o o o o o o o 19300cosuB19390Generator 19530REMFAILUREDECISION Handler 19540PRINT!SELECT a UDK Stancdischarge Can DamageSemiconductor Many Componentsused Thisinstrument Adluctment Procedure- 4g4A/4g4ApServtceVot A a oPreparation 7lu Selectorswttch Adjustment Procedure- 494A/494ApServiceVol O o o o o o o o o o o o o o o o o o o O o o o o o o o o o o o o o o o o o o o o o o o o O o o o o o o o o o o o o o oRrqm TIME/DIV MNL AdJustmantProcedure- 494A/4g4ApServiceVot. .l TIME/DIVAUTO Triggeringfreerun Adiustment Procedure- 4g4Al4g4Ap ServiceVol Test equlpment setup for adiusting the D€flection Amplifier Adfustment Procedure- 4g4Ll4g4ApServtceVot O o o o o o o o o o o o o o o oTriggering EXT AdJustmentProcedure- 494A1494ApService Vot O o o o o o o o o o o o oO o o o o o o o o o o o o o o o o o o o o o o o o o OuFur GarnR1033 nrors Adjustnent Procedure- 4g4A/4g4ApServtceVot O a o O o o o o o o o oO o o o o o o o o o o o o o o o o o o o o o Adjust Log Amptitier =?lRPlo3s-.8 R1012 R102S,R1030 AdrustmentProcedure 4g4Ll4g4ApServtce Vot @o.@@GPt O o a o o o o o o o a o o o a o Adjustment Procedure- 494l4g4Ap ServiceVot A o o o a o o a o o o o o o o o o o o oFilrcsotocr AdJustmentProcedure- 4g4l4g4Ap Service Vot O o o o O a o o oA a o A o O o o LNorE-l O o a o o a o o a a o o o o o o o o o o o o o o O o o o o o o o a SETTTNGS2 RcsctTion Bandwidth Tionbandwtdth $o o3 $o O o o o a aO o a o a o a O o o o o a o o o a o a o o o O o o o O o o o o Ai kHrOotHi O a a a a o o o o a o o o o o o o o o o o O a o a o a o o oMIN RF Atten Triggering Auto Adjustment procedure 4g4Al4g4ApseMce vot O a o o O o o a o OTi#i O o aFrequencyrange AdrustmentProcedure- 4g4A/494Ap Rplo?2/hR1OS4 Frequency To 3.0-7.1 GHz, set AdfustrnentProcedure- 4g4A/4g4ApServtceVol Ot o A o o o AdJustnentProcedure- 494A/4g4ApServtceVot A o o o o o a Lt. a o o a o O a o @@rSnrnasrzen @ Rpzoro O o o o o A o o o o AdjustOption0Z VR BandLevetino Optioninstruments Only AdrustmentProcedure- 4g4A/4g4ApServlceVot,I O a o a o o o o oRFouT OUr Introduction Sectfon6 494A/494ApServicc Vot.1Relativesusceptibilityto Staticdischargedamage Maintenance- 4g4Al4g4ApServlce Vot TroubleshootingAids Maintenance- 494A1494ApServiceVol367-028s,00 Page Diagnostics Troubleshooting Using Theerrormessagedisplay TUNINGFAILURE- 2NDLO Powersupplyoutof Regulation TUNINGFAILURE- 1STLO O a o a oMalntenance- 494A/494ApServlceVol TPl034 GroundRefer€nce Desired Mixerfreo1STLO Setnngaccuracy Auxiliary Synthesizer O o o o o o O o o o o o a 2NDLO Controldiagnosttca Offset SET.540.672KHZ Ting Accu Racy PHASELOCKFAILURE- 1STLO Lockdisabled Press Help Enable PressshifttoexitEnabledpresshelpto Disable Strobefreq O o a o e Shift Pulsestretcher O o a o a TracemodesMalntenance- 4S4Al4g4ApServtceVol Corrective Maintenance Maintenance- 494Al4g4fupService Vof 1R1020 A46A1Rl015 446A1Rl010Selectedcomponents O o o o o a o o o o o o A a SERvIcING TooLs FoRBoARDTffi3.i*,o= MouNTEDcoMPoNENTsMafntenance- 494l4g4Ap ServtceVot.1 HorAlr HepairTerminal Maintenance- 494A/494ApServtceVot.1 Diode Color Code O o c a o oO o o O a a O o E a o o o c o o A o o a o a o o Replacingassembliesand Subassemblies O o O o o o O o c o o o o a A30A57-GPIB Interface Maintenance- 494Al4g4ApServiceVot.1 Sr3- ltILlrxER O o o o o o o o o o o o o o o a o o o o o Page Main PowerSupplyModule Removal EAUloNl @o @@tr\ UpJ Maintenanceadjustments O o a o o o o o o o o o o O o o o o o o o o o o o o o o o Malntenance- 494A/494ApServiceVol EouipmentrequiredforreturnlossadjustmentO o o o o o o o o o o o o O a o o A o o o o o o o o a o O o o o o o a o o o Mafntenance- 494A1494ApServtceVot.1 O o a a o o o o O o o o o o o o o o o o a o o 829lr/lHzCoaxial Band-passFitterAdjustment O a a o a o o a a a o a o a o o oO o o o o o o o o o o O o o o o o o o Maintenance- 494l4g4Ap ServlceVot Malntenance- 494A/4g4ApServiceVol O o o o a o oO a o o O o o o o a o o o o o o o o o o O o o o a o o 17.Corect re3ponsetor g29 MHr tlrlrd and fourth resonators O a o o O o o o o o o o a o oO o o o o o o o o o o Calibrated100 MHz.with +20 kHz accu O o a o o A o o O o oLr.fry- gllpin . DoNorposinouexy op Maintenance- 494A/4g4ApServtce Vot Ffiffi Maintenance- 4g4Al494ApService Vot.1 O a o a o a o o A a o a o o o Mafnfenance- 4g4Ll494ApServtceVot.1 O a a o o a o o A a o a o o o o o Maintenanco- 4g4A/4g4Ap ServlceVol R404OFine TuneRanee O a a o o o a o a o o O a o a A o o FREOSPAN/DV MAX O o o a a o o Malntenance- 494A1494ApServtceVolStart Spur Amplttude Capableof measuring0 Ogmit 2 t\,tt-tz O o o o a a o FREQSPAN/DV MAXFREQSPAN/DIV MAX Autoresoln on Range FREQSPAN/DIV MAX Autoresoln ReflevelMinrf Atten Timeidv HhFr $ f Malntenance- 494A/494ApServlce VolF t Malntenance- 494A/4g4ApServiceVot A o O o o o a o o a a oLl,l Jdl tt Maintenance- 494A/4g4ApServtceVot.1 SettingsA a O o o o a O a C o o o O o o o o O o o o o a oAddressBusTest Maintenance- 494A1494ApServiceVot..t 0xxx U302sSwtTcH Troubleshootingon Instrumentbus Maintenance- 494A/494ApServtceVol Instrument Bus TestO o o o o a o o Yr iffiI ADDRinstrumentbusaddresscommand Responseto ADDRquery DATAinstrumentbus data command CombinedADDRcommandand DATAcommand Malntenance- 494Alttg4ApService VolDATAinstrumentbus dataquery InstrumentBusRegisters X x x 0 0 X x x 0 1 X x x 1 0 InstrumentbusregistersDB7-DBO DB3-DBO O a o A e DBO DB5-DBO ExtmixerRfinput O o o a a DB2DB7-O DB3-DBO Vco LSBDB6 DB2 DBO DB2-DBO Front-PanelRegisters Maintenance 4g4ful4g4ApService Vol TapedatatransferprogramOFF O o o a E oA o o o A o o o a o o Finished O t a O o o o a o O o o O o o o a O o t O o o a a o O o a a o o o a o a o o o o a o o O o o o O o o a o o o o a o o o o o o o o A o o Secton 494A1494Ap Service,Vot Pr signals. Blockdiagrams ShowingmoreRollow O o o o O a o o a o o o o o o o o o a o o O o o o o o Page RF InterfaceCircuits Diagram28 Lst ConverterDiagram12RF Input TheRFINPUT50 connectoracceptstheinputsig O o o o o o o o o o O o o o o o o o o o o o o O o o o o a o o o o o o a o Andpassesdtttreiueniy oroPage O o o o o o O o o o o o o Theoryof Operafon 4g4A/494ApServlce,VotTabte7-1 2NDCONVERTERIF Selection 2472MHz2ND CONVERTERDiagram12 O o o O o o a o o o o o o o oO o o a o o o o o o o o o o o CAvrrYPosr+l+ Theory of Operaton 4g4A/4g4ApService, Vol. .l Ou-Too---lPrecision ExternalCabtes 2182MHz PHASELOCKED2nd LO Diagrams13 O o o o O o a o o o o O a o O a o o O a o O o O o o o O a o a o o o o o o o o a o o a o o Vco MHz 2nd Converter Diagrams15 O a O o a o A o a o O o a a o o oO o o o o o o a o o o a o o o Switchandamplifier A o a o o o o o oOtr 829MHz2nd Conv O o a a a o o o O o o a Page O o a a o o a o o o O o a a o o o o o 110MHztF AMpLtFtERDiagram17 Theory of Operation 4g4Al4g4ApService,VolA o o a 110MHzFTLTERS Diagram17 3rd CONVERTERDiagram17A o o o O o o o O a o A o o o o o o REFERENCELOCKDiagramS0 O o o O o a o O a o O o A o o o o o o a VariabfeResolution Diagrams19, 19,104Id,and Bandwidthselection A o o o o o O o o A a o o o o O o O o o BandLevetingCircuitDiagram20 GalnRequired A o o O o LOc AMp and Detector Diagram22 Fn9 input signat.at a nominal14 dBm, is applied O a o o a 3160316 316 684 O o o A a o o Theory of Operation- 4gA/494Ap Servtce,Vol VIDEOAMpLtFtERDiagram23 FunctionaldescrtptionTheoryof Operation- 4g4ful4g4ApServtce,Vot Theory of Operaton 494l4g4Ap Servlce,Vol 12. Selecdon ol display positlon on lhe log scale VtDEo PROCESSORDAGRAM24 Theory of Operaton 4g4Al4g4ApService,Vol Ffi rffi O o C3026 C2016Filtercomponentcombinations DB2 DB3 DlclTAL STORAGEDiagrams25 Sytemis desisncto opn IT,r-.,.P.,9? O o LI l Theory of Operadon- 4g4N4g4Ap Servtce,Vot.lPage O o O a o o O o o o o O o o o o o a o o o Theoryof Operafon 494A/4g4ApServlce,Vol O o e O o a a A o a a o o DEFLECTIONAMpLtFtERSDiagram27 500 digitalstoragesweep positions. The resultingClisplayappearsas a bright dot sweepingacross O a o o O o o Axisand RF Interface DTAGRAM28 Enables Currentdrivers TransferswitchdriverO o O o o a o o A o O o o o o o o o O a a MHztF high Stateor F829 MHzlF towstate O o A o O o o o O o a o HTGH,VOLTAGESUPPLYDAGRAM29 O o o o o O o o o o o o CRT READOUTDAGRAM30Lf BLANKMSBof the characterdatais not set,the GEN RUNNTNGflip-flopunassertsR/o oFF throughoR Theory of Operatlon 4g4A/4g4Ap Service, Vol Theory of Operation- 4g4Ll4g4ApService,Vot. l O o o o o o o o o o o o o o o o o o o o o o o o o o o oZo-cou I lF-€ OFFTME u1055-d X x x x x x X x o o o o oX o o o o o X . o o o o o O o o o o o o o o o o o o o o o o o o o o o o o o o o o o Theory of Operation- 4g4l4g4Ap Servlce,Vol Oe o \i o Address of Ascii code Skip bit Blank character 58O O o o a o o o o a O o o o o o o o O o a Theory of Opera$on- 494l4g4Ap Servtce,Vol SWEEPDiagram31 Theory of Operaton 494A/494ApService,VolA o o o a o o o o o O a o o o o o a o o A o o O a O a o o o o o o o o 20ssldiv 100D4 D3 D2 D1 do Theory of Operation- 494A/494ApService,Vol Tabte7-12 O a o o a o o o a o o o o oTriggerselectionmodes TriggerMode Freerun Internal Ext€rnal Line TableZ-13 A o a o o o o O a a o a o A o a o A a o o o o a o o o o o O o o o o O a A o o o o o o SPANATTENUATORDiagram32 A o A o o A o o o o a o o Theory ol Operaton 4g4A/494ApService,Vot 20kCalibrationcontrolselectioncodes 1st LO DRTVERDiagram33 O o o o a a a o o A o o a a aXl K3065 x0.1 K3075 x0.01 K4072 X0.01 O o a o o o o o O a a o a O o o o o o o o o o a DB4DB7 Preselectordriver Diagram34 A oO o a a o o o A o O o a o a o a o O o a o o o o oU5031OUTPUTLINES Span Volts Span Volts Theory of Opera0on- 4g4\l4g4Ap Servlce,Vot TabteT-18Preselector Freouencybands Centerfreouencycontrol DIAGRAM35 O o A a a a o O o oA o a o o o o O o a O o o Figure Z-2S. DAC Varlance graph O o O a o o A o RuooeourTheory of Operaton 494l4g4Ap Servlce,Vot O o o a o ADDRESS70 Formats O o a o o o a o C o a o O o o o o o o o Theory of Operation- 4g4ful4g4ApService,Vot O o o O a aFunctionaldescription HARMONICMIXERDiagram36 AUXILIARYSYNTHESZERDiagram37 O a a A o oTheory of OperaUon- 494Al4g4ApServtce,Vot.1 Theoryof Operation- 4g4A/494ApService,Vol O o o o o O a o o o o o a A oPage COUNTERBOARDDiagram38 Phaselocksynthesizer Diagrams39 O e o o o o o o o o o o o O o o aO o o o o e U2025OUTPUTLINES O e o o a o o o o o o o o o Page DIGITALCONTROLDiagram9 Theory of Operation- 494l4g4Ap Service,Vot Theory of Operation- 4g4Ll4g4ApServlce,Vol 30. System memory map Theoryof Operation- 494A/494ApServlce,Vol 31. UOaddr€ssspace Theory of Operation- 4g4hl4g4ApService,Vol O o c oPage A a O o O o o o o o o a o PollbitsBit A o A a o O o a o o o o o A a O o o o o Ff nsrrrcrr qrs crccrLunr O a o O a o o o o o o A a O a o o O a o O o o o O o o a o A o o O o o o o o o o a o o o o o o o o O o o o o o o o o a o o 100 101 CoL 102 Main power Supplyfurnishes all the regulated O o o o a o O o o o o o o103 Theory of Operation- 4g4A/494ApServlce,Vol O a o o o o o o o a o o o o o O o o o A o o o o oTheory of Operaton 494A/494ApServtce,Vot 105 Theory of Operation- 494l4g4Ap Servlce,VotOenanon*l Theory of Operation 4g4Ll4g4ApService, Vot 106 +5 V Voltage ReferenceSupply O o o o o O a a o a o o a a a o o o a o Determiningcomponents 107Page Opl ONs RcV/134Swtss O a o o o o o o o o o O o o O o o o CalibratorOutput cALOUT A o o o o o o o O a o o a o o o o o o o a o o o o o o o O a o O o o o o o o o o o o oFreouency O o o o a o o o A o A a GoesanoffiSymmetry OoultnGffi A o o a o o A o o o o a a o o o a o o o o GeneraltermsVtdeoimarker Gfoesary- 494l4g4Ap Service,Vol O o o o o oFrequencyterms Amplitudeterms A o a o o Digitalstorageterms O o a o o o O a a o o a O o o o o Revisioninformation Manual Part No G556O-00 Flrst prtnilng JAN1987 Revleed O o a a o a o o o o o o a o o O o o o a o 12sSENSmVTY Instrument O o O o a o o A o a o Efr/sN O o o A o a o o O o o o o o o O o O o o o Product see llst Dale2-22-88 Chg. Ref M63911 DeflectionAmplifiertestpointsandadjustments Page5 ol Productsee llst O a o o o o o o o o Performance Checkprocedure O o o o o O o aInstrument Manual A o o o O o O a a Instbument Partno ADD O o o o o O o o o a Perfrmanceheck pRocEDURE change stepr r as foltows Product494N4g4Ap ServiceVolDate 5/u9o O a o o o ServiceVot.1 O a o o o oDate 6/1190 Product494N494Ap RHI LO0Vehticaldisplay Peaiaverage +i\ + \ Resolution Verncal Freouency Bandwidth Display Spaivdiv MHz DB BandwidthMHz 10dB 100kHz DB Bandwidth Limits 60dB Measured Resolutionbandwdith PartiMinnoise Verticaldisplay Narrow Videofilter TIME/DIV Auto Peaivaverage A a a Peavaverage Specification Tercfgnix CHANcE INFoRMAnoNPerformanceVerification Check1 dB Compressionpoint FREQUENCYSPAN/DIV 1 MHz RESOLUTIONBANDWTDTH1 MHz Product SeeLlst Date11SpectrumAnalyzerUnder Test Ref. C1-991 A o a o o O c