Power Supply Troubleshooting Procedure | Tektronix 1705A specification

Maintenance

all obvious defects. In the case of overheated components, determine and correct the cause of overheating before re-applying power.

5.Use successive electrical checks to locate the source of the problem. The primary tool for problem isolation is the oscilloscope. Use the Performance Check Procedure (located in Section 5) to determine if a circuit is operating within specifications. At times it may be necessary to change a calibration adjustment to determine if a circuit is operational, but since this can destroy instrument calibration, care should be exercised. Before changing an adjustment, note its position so that it can be returned to its original setting.

6.Determine the extent of the repair. If the necessary repair is complex, it may be advisable to contact your local Tektronix field office or representative before continuing. If the repair is minor, such as replacing a component, see the parts list for replacement information. Removal and replacement procedures for the assemblies can be found under Corrective Maintenance.

Power Supply Troubleshooting Procedure

NOTE. A review of the power supply theory of operation is recommended before attempting repairs.

The equipment needed to troubleshoot the power supply:

HDigital Multimeter (DMM), with a diode check function

HOscilloscope

H0 to 20 Vdc Variable Power Supply

HClip Lead - to short across a component

HHigh Voltage Probe, ≥1 GΩ input resistance

Introduction The Troubleshooting Procedure for the Power Supply (Assembly A1) is split into two sections, the Low Volts and High Volts Supplies. Start the procedure by determining which section of the Power Supply the problem is in. Apply ac power and turn on the Power Supply. From Table 6-2, determine which symptom the Power Supply exhibits and refer to the corresponding procedure.

Table 6- 2: Power Supply Fault Symptoms

Symptom	Procedure

Line fuse open	Rectifier/Switcher Check (Low Volts)

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1705A Spectrum Monitor

Image 137

Tektronix 1705A instruction manual Power Supply Troubleshooting Procedure, Power Supply Fault Symptoms

Contents

1705A Spectrum Monitor SN B040000 and Above 070-8222-08 Table of Contents Theory of Operation InstallationTable of Contents 1705A Spectrum Monitor Iii Checks and Adjustments Options Maintenance Replaceable Mechanical Parts 10-1 Replaceable Electrical PartsReplaceable Electrical Parts 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 Introduction InstallationPreface Replaceable Mechanical Parts USA Contacting TektronixPreface Preface Xvi Introduction Page Section Introduction Typical Configurations Options AccessoriesIntroduction #73 Optional Accessories Safety Information Full Spectrum DisplaySPAN/DIV CRT Display Power SourceIntroduction Spectrum Display Physical Characteristics Introduction Environmental CharacteristicsCertifications and Compliances EMC CAT Introduction Certifications and Compliances Meters Applications Earth SUN Satellite Using the 1705A for Satellite Communication Vancouver BC Seattle Portland Helena Boise SAN Francisco Band Input SignalsLOS Angeles SAN Diego 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 Band LNB OUTSplitter Input Operating Instructions Page Section Operating Instructions Front-panel Controls and Indicators Operating Instructions Position PowerFilter Input Display 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 Voltage Ratio Power Ratio Reading in dB Voltage Ratio Power RatioOperating Instructions DB Reference Reading in dB Operating Instructions DBm to v Conversion Reading in dBm 75Ω 50Ω Frequency Scale = 10 Divisions Sweep Length = 12 Divisions Minimum Maximum FrequencyMID MHZ Center Frequency Readout70 MHZ 1400 MHZ Center Frequency Tuned AT this Point Point on Trace That Corresponds to Customizing Frequency Readout Offset Adjust Readout ModeMain Menu Readout Position 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 Installation Mechanical InstallationLNB Power Band Input OFF Cabinet Options 875 250105 130 Cabinetizing 1700F02 portable cabinet dimensions Cabinet Securing Screws A WFM7F05 with a blank front panel 1700F06 1700F07 1705A Spectrum Monitor Theory of Operation Page Overview Block DiagramSection Theory of Operation 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 Electrical Instruments Section Checks And AdjustmentsRecommended Equipment List Auxiliary Equipment Performance Check Short-Form ProcedureChecks and Adjustments SMA Male-to-bnc Female Adapter 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 A1 PWR Sply BD A3 Main BDFront Tek Strap Remove the shorting strap 1705A Spectrum MonitorShorting 1705A Spectrum Monitor Page 1705A Spectrum Monitor Page 1705A Spectrum Monitor End of Adjustment Procedure Checks and Adjustments Maintenance Page Cleaning Section Maintenance LOW Power Schott Schottky SignalCmos 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 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 Focus Amplifier Check Maintenance High Volts Supply Fault SymptomsAxis Amplifier Check Grid Drive Check CRT Voltage Check High Voltage Oscillator Check Obtaining Replacement Parts Corrective Maintenance Bezel Removal Mechanical Disassembly/AssemblyMaintenance Test Selectable Components 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 Power Cord Options Field Upgrade KitsPower Cord Options Description of power cord Section Options Ordering Replaceable Electrical Parts Page Parts Ordering Information Using the Replaceable Electrical Parts ListSection Replaceable Electrical Parts Tektronix Part No Column DescriptionsColumn Column 3 Cross Index MFR. Code Number to Manufacturer Spectrum Control INC Weight STAMP INC Fulling Mill Harrisburg PA MSD INC Orange ST DARLINGTON, SC Sobudai Zawa Kanagawa 228 Japan Zman & AssociatesChrome Shibaura Tokyo Japan 2ND Floor NEW Kyoei MINATO-KU Wilhelm Westerman Circuit BD ASSY18V Power Supply Circuit BD Assypower SUPPLY, 1705ACircuit BD Assyfront Panel Circuit BD Assymain Board ASSY,1705A CAP,FXD,PLSTC100PF,5%,1600VDC/500VAC IAL,MIIN,BULK CAP,FXD,CER DI470PF,20%,100V TUBULAR,MI A1DS1 LAMP,GLOW135V MAX,1.9MA,C2A-T,WIRE LeadA1DS2 A1DS3 SQ,SIDE ADJUSTT&R SQ,TOP AdjustbulkRES,FXD,CMPSN1.5M OHM,5%,1W RES,FXD,CMPSN2.2M OHM,5%,0.5W IAL,T&R,SMALL Body RES,FXD,FILM5K OHM,0.1%,0.2W,TC=T9REELED,SMALL Body RES,FXDMETAL FILM,100K OHM,1%,0.2W,TC=100 WIRED,1705A SQ,TOP ADJUST,T&RRES,THERMAL5 OHM,10%,7A/DEG C RES,FXD,CMPSN2.4K OHM,5%,2W Part of A2DS313 LED ASSYDIR1CA ASSY,SP,ELEC34,26 AWG,5.0 L RES,VAR,PNLCP,20K OHM,20%,0.5W,LINEAR,W PLATE,ELEC Shldcircuit Board BUS,CNDCTSHIELD,ELECCIRCUIT Board SHIELD,ELEC1705A,BRS UVX1H330MAA CAP,FXD,ELCTLT33UF,+50-20%,35WVDCCAP,VAR,CER DI9-45PF,200V CAP,VAR,PLSTC1-3.5PF,500V A3CR1 CAP,FXD,MICA DI98PF,5%,500VA3CR2 DIO,SIGFAST RCVRY70V,200MA,100NS,COM FLTR,BANDPASS A3FL1A3FL2 A3FL3 COIL,RFFIXED,15NH COIL,RFFIXED,45NHCOIL,RFFIXED,64UH COIL,RFFIXED,505NH RES NTWK,FXD,FI10K OHM,20%,9RES ADJUSTT&RGF06UT 2K GF06UT 5K RES,FXD,FILM3.4K OHM,1%,0.2W,TC=T0 RES,FXD,FILM115K OHM,1%,0.2W,TC=T0RES,FXD,FILM237K 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 Percent RES,FXD,FILM1M OHM.1%,0.2W,TC=T0CRB20FXE1K62 CRB20FXE9K35 RES,VAR,NONWWTRMR,100 OHM,20%,0.5W LIN RES,FXD,FILM2.1K OHM,1%,0.2W,TC=T0RES,FXD,WW6.3K OHM,1%,3W CRB20FXE210E GF06UT 1K Loss 10DB,PKG 7.2MM SQ,6.8MM HI RES,FXD,FILM187K OHM,1%,0.2W,TC=T0IC,CONVCMOS,A/D8-BIT,32US,SAR,DIFF IN,SER MICROCKT,DGTLMICROCOMPUTER,8 BIT IC,LINBIPOLAR,AMPLRF AMP,20DB IC,MISCCMOS,ANALOG Swquad SPST,100IC,DGTLTTL,BFR/DRVRHEX INV, OC, HI MIXER,FREQ1-500MHZ CTR,0.385 H,30 GLD,BLK,JUMPER CONN,BOXSHUNT/SHORTINGFEM,STR,1 X 2,0.1TAIL,30 GLD IAL,MI,T&R RES,FXD,WW1 OHM,5%,2W RES,FXD,FILM267K OHM,1%,0.2W,TC=T0Order by Desc RES,FXD,CMPSN1K OHM,5%,0.50W CONN,HDRPCB/WIREWRAP,MALE,STR,1 X 4,0.150 CONN,HDRPCB/WIREWRAP,MALE,STR,1 X 7,0.15CORE,EMTOROID,FERRITE COIL,RFFIXED,150NH Controlled 0LUA3 A10SKT1CONN,RF Plug CA ASSY,SP Replaceable Electrical Parts Diagrams/Circuit Board Illustrations Page Symbols Diagrams/Circuit Board IllustrationsAssembly Numbers Component ValuesPage 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 Ramp Generator Band LinearityMarker Generator Schematic Diagram 4 Component Locator Chart Amplifier DeflectionFilter Buffers Schematic Diagram 5 Component Locator Chart Microprocessor 1705A Spectrum MonitorMicroprocessor Trace Schematic Diagram 6 Component Locator Chart A2 Front Panel Board 1705A Spectrum Monitor Front Panel & 18V Supply See Parts List for Effective Serial Number Ranges A1 Power Supply BoardA1 Power Supply Board Component Locator Error SwitcherLine Rectifier Output Filters A10 CRT Socket Board Front of Board Schematic Diagram 8 Component Locator Chart 1705A Spectrum Monitor High Volts Power Supply Error AMPHV OSC Grid DrivePage Replaceable Mechanical Parts Page Section Replaceable Mechanical Parts Using the Replaceable Mechanical Parts List Replaceable Mechanical Parts Qty ColumnThis indicates the quantity of mechanical parts used Indicates actual manufacturer’s part number Richco Panduit Corp RidgelandCHICAGO, IL Nelson Name Plate CO Casitas COVER,HOUSINGALUMINUM Circuit BD Assypower Supply See A1 Repl Mounting PartsFRAME,CRTBEZEL SCREW,MACHINE6-32 X 0.875,PNH,SST FRAME,CHASSISSAFETY Controlled HOUSING,CKT BdaluminumSCREW,MACHINE6-32 X 0.188,PNH,STL IN/OUT See A6 Repl Mounting Parts CLAMP,LOOP0.375 ID,PLASTIC,SAFETY CON Trolled Standard AccessoriesStandard only Optional Accessories CA ASSY,CRTDISCRETE,ANODE LEAD,CRT,1,22 A10