Axis Amplifier | Tektronix 1705A instruction

Theory of Operation

Power Supply Outputs CR4 is the high voltage rectifier. Filter capacitors C3, C4, and C8 work with CR4 to provide -2530 V to the crt cathode. U1 is a four-times multiplier providing +11 kV to the crt anode.

Focus Amplifier Q1 and Q2 form an operational amplifier that sets the voltage at the bottom of the focus divider. The front-panel FOCUS pot determines the voltage at the bottom of the focus divider. The Center Focus control, R11, is set for optimum beam focus, as viewed on the crt, with the front-panel FOCUS control set to mid range. Once the Center Focus adjustment has been set, adjusting the front-panel FOCUS control changes the voltage at the bottom end of the divider and, consequently, the voltage on the crt focus anode.

Grid Drive Circuit The cathode of the crt is at a -2530 V potential with the grid coupled to the Z–Axis Amplifier by the grid drive circuit. The grid is approximately 75 V negative with respect to the cathode. The 200 V p-p sine wave present at the cathode of CR8 is input to the Grid Drive circuit where it is clipped for use as the crt control grid bias.

The sine wave from the cathode of CR8 is coupled through R47 to a clipping circuit consisting of CR5 and CR6. Clipping level for the positive excursion of the sine wave is set by the CRT Bias adjustment, R58. The negative clipping level is set by the front-panel INTENSITY control through the Z-Axis Amplifier. The clipped sine wave is coupled through C11 to a rectifier made up of CR1 and CR3. The rectified, clipped sine wave is the crt control grid bias voltage. C9 couples the blanking signal from the Z-Axis Amplifier to the crt control grid. DS1 and DS2 limit the crt grid to cathode voltage at instrument turn on or off. DS3 limits the crt heater to cathode voltage.

Z-Axis Amplifier

This is an inverting amplifier with negative feedback. R22 is the feedback resistor while R7, R20, and R33 act to maintain the summing junction at +5 V. Without any Z–Axis input current, the amplifier output is approximately +10 V. Negative Z–Axis input current will cause the output to go positive.

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1705A Spectrum Monitor

Image 91

Tektronix 1705A instruction manual Axis Amplifier

Contents

1705A Spectrum Monitor SN B040000 and Above 070-8222-08 Table of Contents Table of Contents InstallationTheory of Operation 1705A Spectrum Monitor Iii Checks and Adjustments Options Maintenance Replaceable Electrical Parts Replaceable Electrical PartsReplaceable Mechanical Parts 10-1 Simulation of a 1705A Full SPAN/DIV display List of Figures 1705A Spectrum Monitor Vii Considerations for custom installation of an instrument Viii List of Tables General Safety Summary General Safety Summary Service Safety Summary Service Safety Summary Xii Preface InstallationIntroduction Replaceable Mechanical Parts Preface Contacting TektronixUSA Preface Xvi Introduction Page Section Introduction Typical Configurations #73 AccessoriesOptions Introduction Optional Accessories Safety Information SPAN/DIV Spectrum DisplayFull Introduction Spectrum Display Power SourceCRT Display EMC Introduction Environmental CharacteristicsPhysical Characteristics Certifications and Compliances CAT Introduction Certifications and Compliances Meters Applications Earth SUN Satellite Using the 1705A for Satellite Communication SAN Diego Band Input SignalsVancouver BC Seattle Portland Helena Boise SAN Francisco LOS Angeles Zeroing in on a Satellite Tek 12.20 GHZ Frequency and Number Down Link Transponder Horizontal Vertical Polarization GHZ Looking at Exciters with the 70 MHz Input Miscellaneous Uses for the 1705A Input LNB OUTBand Splitter Operating Instructions Page Section Operating Instructions Front-panel Controls and Indicators Display Position PowerOperating Instructions Filter Input SPAN/DIV Variable control that adjusts the display brightness Position Rear- Panel Connectors Spectrum Monitor Holder for the instrument’s mains fuse 1400 MHZ Powering- up 1705A graticule scale Measurement Graticule Reading in dB Reading in dB Voltage Ratio Power RatioVoltage Ratio Power Ratio Operating Instructions DB Reference Operating Instructions DBm to v Conversion Reading in dBm 75Ω 50Ω MID Minimum Maximum FrequencyFrequency Scale = 10 Divisions Sweep Length = 12 Divisions 70 MHZ Center Frequency ReadoutMHZ 1400 MHZ Center Frequency Tuned AT this Point Point on Trace That Corresponds to Customizing Frequency Readout Readout Position Readout ModeOffset Adjust Main Menu 12.00 GHZ Locating Ku- Band Satellites Basic Operating Procedure Satcom K2 G-STAR City 1705A Spectrum Monitor Operating Instructions Page Page Installation Page Electrical Installation Section Installation Cabinet Options Mechanical InstallationInstallation LNB Power Band Input OFF 130 250875 105 Cabinetizing 1700F02 portable cabinet dimensions Cabinet Securing Screws A WFM7F05 with a blank front panel 1700F06 1700F07 1705A Spectrum Monitor Theory of Operation Page Section Theory of Operation Block DiagramOverview Theory of Operation Front Panel Diagram RF Input Diagram If Amplifier Diagram Resolution Filter and Log Detector Sweep Generator Diagram Start Display Deflection Amplifiers Diagram Vertical Deflection Amplifier Microprocessor Diagram Front Panel Diagram High Load LOW Load Average Low Voltage Power Supply Diagram Pulse Width Modulator Theory of Operation High Voltage Power Supply Diagram Axis Amplifier Pinout of the CRT Socket 1705A Spectrum Monitor CRT The pinout for the CRT is shown in Figure Theory of Operation Checks and Adjustments Page Recommended Equipment List Section Checks And AdjustmentsElectrical Instruments Auxiliary Equipment Checks and Adjustments SMA Male-to-bnc Female Adapter Short-Form ProcedurePerformance Check 1705A Spectrum Monitor Long Form Procedure Checks and Adjustments Preliminary Control Settings Page Marker Here Marker is +/-- 1 Minor Division from Here Checks and Adjustments 1705A Spectrum Monitor Page Variable Autotransformer L-BAND Input Marker Here Graticule Line Disregard UHF Sine Wave Generator Page End of the Performance Check Procedure Short- Form Procedure Adjustment Procedure Video SPAN/DIV Full Center Frequency Preliminary Setup Front A3 Main BDA1 PWR Sply BD Tek Shorting Remove the shorting strap 1705A Spectrum MonitorStrap 1705A Spectrum Monitor Page 1705A Spectrum Monitor Page 1705A Spectrum Monitor End of Adjustment Procedure Checks and Adjustments Maintenance Page Cleaning Section Maintenance ECL Schottky SignalLOW Power Schott Cmos Troubleshooting Diagnostic Routines Nonvolatile 2444 RAM Test Reading Data Stored AT 60H to 7F in Processor Error Cannot Read or Write Press Input KEY to Exit Troubleshooting Aids Circuit board assembly locations Major Assembly Interconnection PIN ROW B ROW a Power Supply Fault Symptoms Power Supply Troubleshooting Procedure Low Volts Supply Maintenance Power Supply Fault Symptoms Maintenance Rectifier/Switcher Check High Volts Supply Grid Drive Check Maintenance High Volts Supply Fault SymptomsFocus Amplifier Check Axis Amplifier Check CRT Voltage Check High Voltage Oscillator Check Obtaining Replacement Parts Corrective Maintenance Maintenance Test Selectable Components Mechanical Disassembly/AssemblyBezel Removal Graticule Light Removal and Replacement Replacing the CRT Removal of the CRT Removal of the Rear Panel Removal of Front- Panel Assembly Removing the L- Band Tuner Removal Replacement of the Main Board Removal Replacement of the Power Supply Board Front Removing the LNB Power Supply Board Repackaging 1705A Spectrum Monitor Options Page Section Options Field Upgrade KitsPower Cord Options Power Cord Options Description of power cord Ordering Replaceable Electrical Parts Page Section Replaceable Electrical Parts Using the Replaceable Electrical Parts ListParts Ordering Information Column 3 Column DescriptionsTektronix Part No Column MSD INC Orange ST DARLINGTON, SC Spectrum Control INC Weight STCross Index MFR. Code Number to Manufacturer AMP INC Fulling Mill Harrisburg PA Wilhelm Westerman Zman & AssociatesSobudai Zawa Kanagawa 228 Japan Chrome Shibaura Tokyo Japan 2ND Floor NEW Kyoei MINATO-KU Circuit BD Assymain Board ASSY,1705A Circuit BD Assypower SUPPLY, 1705ACircuit BD ASSY18V Power Supply Circuit BD Assyfront Panel CAP,FXD,CER DI470PF,20%,100V TUBULAR,MI IAL,MICAP,FXD,PLSTC100PF,5%,1600VDC/500VAC IN,BULK A1DS3 LAMP,GLOW135V MAX,1.9MA,C2A-T,WIRE LeadA1DS1 A1DS2 RES,FXD,CMPSN2.2M OHM,5%,0.5W SQ,TOP AdjustbulkSQ,SIDE ADJUSTT&R RES,FXD,CMPSN1.5M OHM,5%,1W RES,FXDMETAL FILM,100K OHM,1%,0.2W,TC=100 RES,FXD,FILM5K OHM,0.1%,0.2W,TC=T9IAL,T&R,SMALL Body REELED,SMALL Body RES,FXD,CMPSN2.4K OHM,5%,2W SQ,TOP ADJUST,T&RWIRED,1705A RES,THERMAL5 OHM,10%,7A/DEG C RES,VAR,PNLCP,20K OHM,20%,0.5W,LINEAR,W LED ASSYDIR1Part of A2DS313 CA ASSY,SP,ELEC34,26 AWG,5.0 L SHIELD,ELEC1705A,BRS BUS,CNDCTPLATE,ELEC Shldcircuit Board SHIELD,ELECCIRCUIT Board CAP,VAR,PLSTC1-3.5PF,500V CAP,FXD,ELCTLT33UF,+50-20%,35WVDCUVX1H330MAA CAP,VAR,CER DI9-45PF,200V DIO,SIGFAST RCVRY70V,200MA,100NS,COM CAP,FXD,MICA DI98PF,5%,500VA3CR1 A3CR2 A3FL3 A3FL1FLTR,BANDPASS A3FL2 COIL,RFFIXED,505NH COIL,RFFIXED,45NHCOIL,RFFIXED,15NH COIL,RFFIXED,64UH GF06UT 2K ADJUSTT&RRES NTWK,FXD,FI10K OHM,20%,9RES GF06UT 5K RES,FXD,FILM237K OHM,1%,0.2W,TC=T0 RES,FXD,FILM115K OHM,1%,0.2W,TC=T0RES,FXD,FILM3.4K OHM,1%,0.2W,TC=T0 RES,VAR,NONWWTRMR,250 OHM,20%,0.5W LIN RES,FXD,FILM7.5K OHM,1%,0.2W,TC=T0 CRB20FXE9K35 RES,FXD,FILM1M OHM.1%,0.2W,TC=T0Percent CRB20FXE1K62 CRB20FXE210E RES,FXD,FILM2.1K OHM,1%,0.2W,TC=T0RES,VAR,NONWWTRMR,100 OHM,20%,0.5W LIN RES,FXD,WW6.3K OHM,1%,3W GF06UT 1K MICROCKT,DGTLMICROCOMPUTER,8 BIT RES,FXD,FILM187K OHM,1%,0.2W,TC=T0Loss 10DB,PKG 7.2MM SQ,6.8MM HI IC,CONVCMOS,A/D8-BIT,32US,SAR,DIFF IN,SER MIXER,FREQ1-500MHZ IC,MISCCMOS,ANALOG Swquad SPST,100IC,LINBIPOLAR,AMPLRF AMP,20DB IC,DGTLTTL,BFR/DRVRHEX INV, OC, HI IAL,MI,T&R CONN,BOXSHUNT/SHORTINGFEM,STR,1 X 2,0.1CTR,0.385 H,30 GLD,BLK,JUMPER TAIL,30 GLD RES,FXD,CMPSN1K OHM,5%,0.50W RES,FXD,FILM267K OHM,1%,0.2W,TC=T0RES,FXD,WW1 OHM,5%,2W Order by Desc COIL,RFFIXED,150NH CONN,HDRPCB/WIREWRAP,MALE,STR,1 X 7,0.15CONN,HDRPCB/WIREWRAP,MALE,STR,1 X 4,0.150 CORE,EMTOROID,FERRITE CA ASSY,SP A10SKT1Controlled 0LUA3 CONN,RF Plug Replaceable Electrical Parts Diagrams/Circuit Board Illustrations Page Component Values Diagrams/Circuit Board IllustrationsSymbols Assembly NumbersPage 1705A Spectrum Monitor A3 Main Board Component Locator With cross-references to schematic diagrams 1, 2, 3, 4, A5 70 MHz Tuner Board A3 Main Board Schematic Diagram 1 Component Locator Chart 1705A Spectrum Monitor RF Input Local Oscillator Schematic Diagram 2 Component Locator Chart 1705A Spectrum Monitor If Amplifier Resolution Filter & LOG Detector Schematic Diagram 3 Component Locator Chart Generator Band LinearityRamp Generator Marker Schematic Diagram 4 Component Locator Chart Buffers DeflectionAmplifier Filter Schematic Diagram 5 Component Locator Chart Trace 1705A Spectrum MonitorMicroprocessor Microprocessor Schematic Diagram 6 Component Locator Chart A2 Front Panel Board 1705A Spectrum Monitor Front Panel & 18V Supply A1 Power Supply Board Component Locator A1 Power Supply BoardSee Parts List for Effective Serial Number Ranges Output Filters SwitcherError Line Rectifier A10 CRT Socket Board Front of Board Schematic Diagram 8 Component Locator Chart Grid Drive Error AMP1705A Spectrum Monitor High Volts Power Supply HV OSCPage Replaceable Mechanical Parts Page Section Replaceable Mechanical Parts Using the Replaceable Mechanical Parts List Indicates actual manufacturer’s part number Qty ColumnReplaceable Mechanical Parts This indicates the quantity of mechanical parts used Nelson Name Plate CO Casitas Panduit Corp RidgelandRichco CHICAGO, IL SCREW,MACHINE6-32 X 0.875,PNH,SST Circuit BD Assypower Supply See A1 Repl Mounting PartsCOVER,HOUSINGALUMINUM FRAME,CRTBEZEL IN/OUT See A6 Repl Mounting Parts HOUSING,CKT BdaluminumFRAME,CHASSISSAFETY Controlled SCREW,MACHINE6-32 X 0.188,PNH,STL CA ASSY,CRTDISCRETE,ANODE LEAD,CRT,1,22 Standard AccessoriesCLAMP,LOOP0.375 ID,PLASTIC,SAFETY CON Trolled Standard only Optional Accessories A10