High Voltage Power Supply Diagram | Tektronix 1705A manual

Theory of Operation

High Voltage Power Supply

Diagram 8

The High Voltage Power Supply generates the heater, cathode, control grid, focus anode, and post accelerating potentials required to display the outputs of the Vertical and Horizontal Output Amplifiers.

HV Osc and Error Amp The High Voltage Power Supply is generated by a sine-wave oscillator and step-up transformer. Q6 and T1 are the principal elements of an Armstrong oscillator running at about 22 kHz. Error Amplifier U2 regulates the +100 V output and keeps the High Voltage Power Supply constant under varying load conditions by controlling the base current to Q6. The +100 V output is regulated directly, while the High Voltage Power Supply is indirectly regulated through a current feedback circuit.

R48, C16, R60, and R64 form the High Voltage Power Supply current feedback circuit. As the current from the High Voltage Power Supply is increased, the voltage to the + side of the Error Amplifier (U2) increases, which increases the base drive to Q6, the HV Osc. This current feedback compromises the regula- tion of the +100 V supply to keep the high voltage constant with varying intensities.

C66 and Q10 are a start delay circuit that holds the Error Amplifier output low, through CR30, until C66 is charged. Delaying the start of the high voltage oscillator allows the Low Voltage Power Supply to start, unencumbered by the load from the high voltage oscillator.

1705A Spectrum Monitor

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Tektronix 1705A instruction manual High Voltage Power Supply Diagram

Contents

1705A Spectrum Monitor SN B040000 and Above 070-8222-08 Table of Contents Installation Table of ContentsTheory of Operation Checks and Adjustments 1705A Spectrum Monitor Iii Maintenance Options Replaceable Electrical Parts Replaceable Electrical PartsReplaceable Mechanical Parts 10-1 List of Figures Simulation of a 1705A Full SPAN/DIV display Considerations for custom installation of an instrument 1705A Spectrum Monitor Vii List of Tables Viii General Safety Summary General Safety Summary Service Safety Summary Service Safety Summary Xii Installation PrefaceIntroduction Replaceable Mechanical Parts Contacting Tektronix PrefaceUSA Preface Xvi Introduction Page Typical Configurations Section Introduction Introduction AccessoriesOptions #73 Safety Information Optional Accessories Spectrum Display SPAN/DIVFull Power Source Introduction Spectrum DisplayCRT Display Certifications and Compliances Introduction Environmental CharacteristicsPhysical Characteristics EMC Introduction Certifications and Compliances CAT Meters Applications SUN Satellite Earth Using the 1705A for Satellite Communication LOS Angeles Band Input SignalsVancouver BC Seattle Portland Helena Boise SAN Francisco SAN Diego Zeroing in on a Satellite Tek 12.20 GHZ Horizontal Vertical Polarization Frequency and Number Down Link Transponder Looking at Exciters with the 70 MHz Input GHZ Miscellaneous Uses for the 1705A Splitter LNB OUTBand Input Operating Instructions Page Front-panel Controls and Indicators Section Operating Instructions Filter Input Position PowerOperating Instructions Display Variable control that adjusts the display brightness SPAN/DIV Rear- Panel Connectors Position Holder for the instrument’s mains fuse Spectrum Monitor Powering- up 1400 MHZ Measurement Graticule 1705A graticule scale Operating Instructions DB Reference Reading in dB Voltage Ratio Power RatioVoltage Ratio Power Ratio Reading in dB 75Ω 50Ω Operating Instructions DBm to v Conversion Reading in dBm Minimum Maximum Frequency MIDFrequency Scale = 10 Divisions Sweep Length = 12 Divisions Center Frequency Readout 70 MHZMHZ 1400 MHZ Point on Trace That Corresponds to Center Frequency Tuned AT this Point Customizing Frequency Readout Main Menu Readout ModeOffset Adjust Readout Position 12.00 GHZ Basic Operating Procedure Locating Ku- Band Satellites City Satcom K2 G-STAR 1705A Spectrum Monitor Operating Instructions Page Page Installation Page Section Installation Electrical Installation LNB Power Band Input OFF Mechanical InstallationInstallation Cabinet Options 105 250875 130 1700F02 portable cabinet dimensions Cabinetizing Cabinet Securing Screws A WFM7F05 with a blank front panel 1700F06 1700F07 1705A Spectrum Monitor Theory of Operation Page Block Diagram Section Theory of OperationOverview 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 LOW Load Average High Load Low Voltage Power Supply Diagram Pulse Width Modulator Theory of Operation High Voltage Power Supply Diagram Axis Amplifier CRT The pinout for the CRT is shown in Figure Pinout of the CRT Socket 1705A Spectrum Monitor Theory of Operation Checks and Adjustments Page Section Checks And Adjustments Recommended Equipment ListElectrical Instruments Auxiliary Equipment Short-Form Procedure Checks and Adjustments SMA Male-to-bnc Female AdapterPerformance 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 Disregard Marker Here Graticule Line UHF Sine Wave Generator Page End of the Performance Check Procedure Adjustment Procedure Short- Form Procedure Preliminary Setup Video SPAN/DIV Full Center Frequency A3 Main BD FrontA1 PWR Sply BD Tek Remove the shorting strap 1705A Spectrum Monitor ShortingStrap 1705A Spectrum Monitor Page 1705A Spectrum Monitor Page 1705A Spectrum Monitor End of Adjustment Procedure Checks and Adjustments Maintenance Page Section Maintenance Cleaning Cmos Schottky SignalLOW Power Schott ECL 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 ROW B ROW a PIN Power Supply Troubleshooting Procedure Power Supply Fault Symptoms Maintenance Power Supply Fault Symptoms Low Volts Supply Maintenance Rectifier/Switcher Check High Volts Supply Axis Amplifier Check Maintenance High Volts Supply Fault SymptomsFocus Amplifier Check Grid Drive Check High Voltage Oscillator Check CRT Voltage Check Corrective Maintenance Obtaining Replacement Parts Mechanical Disassembly/Assembly Maintenance Test Selectable ComponentsBezel Removal Graticule Light Removal and Replacement Removal of the CRT Replacing the CRT Removal of Front- Panel Assembly Removal of the Rear Panel Removing the L- Band Tuner Removal Replacement of the Main Board Removal Replacement of the Power Supply Board Removing the LNB Power Supply Board Front Repackaging 1705A Spectrum Monitor Options Page Power Cord Options Description of power cord Field Upgrade KitsPower Cord Options Section Options Ordering Replaceable Electrical Parts Page Using the Replaceable Electrical Parts List Section Replaceable Electrical PartsParts Ordering Information Column Column DescriptionsTektronix Part No Column 3 AMP INC Fulling Mill Harrisburg PA Spectrum Control INC Weight STCross Index MFR. Code Number to Manufacturer MSD INC Orange ST DARLINGTON, SC Chrome Shibaura Tokyo Japan 2ND Floor NEW Kyoei MINATO-KU Zman & AssociatesSobudai Zawa Kanagawa 228 Japan Wilhelm Westerman Circuit BD Assyfront Panel Circuit BD Assypower SUPPLY, 1705ACircuit BD ASSY18V Power Supply Circuit BD Assymain Board ASSY,1705A IN,BULK IAL,MICAP,FXD,PLSTC100PF,5%,1600VDC/500VAC CAP,FXD,CER DI470PF,20%,100V TUBULAR,MI A1DS2 LAMP,GLOW135V MAX,1.9MA,C2A-T,WIRE LeadA1DS1 A1DS3 RES,FXD,CMPSN1.5M OHM,5%,1W SQ,TOP AdjustbulkSQ,SIDE ADJUSTT&R RES,FXD,CMPSN2.2M OHM,5%,0.5W REELED,SMALL Body RES,FXD,FILM5K OHM,0.1%,0.2W,TC=T9IAL,T&R,SMALL Body RES,FXDMETAL FILM,100K OHM,1%,0.2W,TC=100 RES,THERMAL5 OHM,10%,7A/DEG C SQ,TOP ADJUST,T&RWIRED,1705A RES,FXD,CMPSN2.4K OHM,5%,2W CA ASSY,SP,ELEC34,26 AWG,5.0 L LED ASSYDIR1Part of A2DS313 RES,VAR,PNLCP,20K OHM,20%,0.5W,LINEAR,W SHIELD,ELECCIRCUIT Board BUS,CNDCTPLATE,ELEC Shldcircuit Board SHIELD,ELEC1705A,BRS CAP,VAR,CER DI9-45PF,200V CAP,FXD,ELCTLT33UF,+50-20%,35WVDCUVX1H330MAA CAP,VAR,PLSTC1-3.5PF,500V A3CR2 CAP,FXD,MICA DI98PF,5%,500VA3CR1 DIO,SIGFAST RCVRY70V,200MA,100NS,COM A3FL2 A3FL1FLTR,BANDPASS A3FL3 COIL,RFFIXED,64UH COIL,RFFIXED,45NHCOIL,RFFIXED,15NH COIL,RFFIXED,505NH ADJUSTT&R GF06UT 2KRES NTWK,FXD,FI10K OHM,20%,9RES GF06UT 5K RES,FXD,FILM115K OHM,1%,0.2W,TC=T0 RES,FXD,FILM237K OHM,1%,0.2W,TC=T0RES,FXD,FILM3.4K OHM,1%,0.2W,TC=T0 RES,FXD,FILM7.5K OHM,1%,0.2W,TC=T0 RES,VAR,NONWWTRMR,250 OHM,20%,0.5W LIN CRB20FXE1K62 RES,FXD,FILM1M OHM.1%,0.2W,TC=T0Percent CRB20FXE9K35 RES,FXD,WW6.3K OHM,1%,3W RES,FXD,FILM2.1K OHM,1%,0.2W,TC=T0RES,VAR,NONWWTRMR,100 OHM,20%,0.5W LIN CRB20FXE210E GF06UT 1K IC,CONVCMOS,A/D8-BIT,32US,SAR,DIFF IN,SER RES,FXD,FILM187K OHM,1%,0.2W,TC=T0Loss 10DB,PKG 7.2MM SQ,6.8MM HI MICROCKT,DGTLMICROCOMPUTER,8 BIT IC,DGTLTTL,BFR/DRVRHEX INV, OC, HI IC,MISCCMOS,ANALOG Swquad SPST,100IC,LINBIPOLAR,AMPLRF AMP,20DB MIXER,FREQ1-500MHZ TAIL,30 GLD CONN,BOXSHUNT/SHORTINGFEM,STR,1 X 2,0.1CTR,0.385 H,30 GLD,BLK,JUMPER IAL,MI,T&R Order by Desc RES,FXD,FILM267K OHM,1%,0.2W,TC=T0RES,FXD,WW1 OHM,5%,2W RES,FXD,CMPSN1K OHM,5%,0.50W CORE,EMTOROID,FERRITE CONN,HDRPCB/WIREWRAP,MALE,STR,1 X 7,0.15CONN,HDRPCB/WIREWRAP,MALE,STR,1 X 4,0.150 COIL,RFFIXED,150NH CONN,RF Plug A10SKT1Controlled 0LUA3 CA ASSY,SP Replaceable Electrical Parts Diagrams/Circuit Board Illustrations Page Assembly Numbers Diagrams/Circuit Board IllustrationsSymbols Component ValuesPage 1705A Spectrum Monitor With cross-references to schematic diagrams 1, 2, 3, 4, A3 Main Board Component Locator A3 Main Board A5 70 MHz Tuner Board Schematic Diagram 1 Component Locator Chart Local Oscillator 1705A Spectrum Monitor RF Input Schematic Diagram 2 Component Locator Chart Resolution Filter & LOG Detector 1705A Spectrum Monitor If Amplifier Schematic Diagram 3 Component Locator Chart Marker Band LinearityRamp Generator Generator Schematic Diagram 4 Component Locator Chart Filter DeflectionAmplifier Buffers Schematic Diagram 5 Component Locator Chart Microprocessor 1705A Spectrum MonitorMicroprocessor Trace Schematic Diagram 6 Component Locator Chart 1705A Spectrum Monitor Front Panel & 18V Supply A2 Front Panel Board A1 Power Supply Board A1 Power Supply Board Component LocatorSee Parts List for Effective Serial Number Ranges Line Rectifier SwitcherError Output Filters Schematic Diagram 8 Component Locator Chart A10 CRT Socket Board Front of Board HV OSC Error AMP1705A Spectrum Monitor High Volts Power Supply Grid DrivePage Replaceable Mechanical Parts Page Using the Replaceable Mechanical Parts List Section Replaceable Mechanical Parts This indicates the quantity of mechanical parts used Qty ColumnReplaceable Mechanical Parts Indicates actual manufacturer’s part number CHICAGO, IL Panduit Corp RidgelandRichco Nelson Name Plate CO Casitas FRAME,CRTBEZEL Circuit BD Assypower Supply See A1 Repl Mounting PartsCOVER,HOUSINGALUMINUM SCREW,MACHINE6-32 X 0.875,PNH,SST SCREW,MACHINE6-32 X 0.188,PNH,STL HOUSING,CKT BdaluminumFRAME,CHASSISSAFETY Controlled IN/OUT See A6 Repl Mounting Parts Standard only Optional Accessories Standard AccessoriesCLAMP,LOOP0.375 ID,PLASTIC,SAFETY CON Trolled CA ASSY,CRTDISCRETE,ANODE LEAD,CRT,1,22 A10