Tektronix TDS 460A, TDS 430A, TDS 420A Service Manual

Service Manual

TDS 420A, TDS 430A & TDS 460A Digitizing Oscilloscopes

070-9703-04

This document applies to instruments with serial numbers B050000 and above.

Warning

The servicing instructions are for use by qualified personnel only. To avoid personal injury, do not perform any servicing unless you are qualified to do so. Refer to the Safety Summary prior to performing service.

that in all previously published material. Specifications and price change privileges reserved. Printed in the U.S.A. T ektronix, Inc., P.O. Box 1000, Wilsonville, OR 97070–1000 TEKTRONIX and TEK are registered trademarks of T ektronix, Inc. KlipChip is a trademark of T ektronix, Inc.

WARRANTY

T ektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship for a period of three (3) years from the date of shipment. If a product proves defective during this warranty period, T ektronix, at its option, either will repair the defective product without charge for parts and labor, or will provide a replacement in exchange for the defective product.

In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the warranty period and make suitable arrangements for the performance of service. Customer shall be responsible for packaging and shipping the defective product to the service center designated by T ektronix, with shipping charges prepaid. T ektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the T ektronix service center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and any other charges for products returned to any other locations.

This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate maintenance and care. T ektronix shall not be obligated to furnish service under this warranty a) to repair damage resulting from attempts by personnel other than T ektronix representatives to install, repair or service the product; b) to repair damage resulting from improper use or connection to incompatible equipment; c) to repair any damage or malfunction caused by the use of non-T ektronix supplies; or d) to service a product that has been modified or integrated with other products when the effect of such modification or integration increases the time or difficulty of servicing the product.

THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY TO REP AIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY. TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT , SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

Specifications

Operating Information

List of Figures iii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

List of Tables vi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General Safety Summary ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Service Safety Summary xi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preface xiii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Introduction xvi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Before Servicing xvi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Strategy for Servicing xvi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

T ektronix Service xvii. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Product Description 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Nominal Traits 1–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Warranted Characteristics 1–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Typical Characteristics 1–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Installation 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Supplying Operating Power 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating Environment 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Applying and Interrupting Power 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repackaging Instructions 2–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Installed Options 2–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operating Information 2–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Screen Layout 2–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Basic Procedures 2–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Theory of Operation

Theory of Operation 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Logic Conventions 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Module Overview 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance Verification

Performance Verification Procedures 4–1. . . . . . . . . . . . . . . . . . . . . . . . . .

Brief Procedures 4–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Self Tests 4–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Functional T ests 4–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance Tests 4–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Prerequisites 4–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Equipment Required 4–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

T est Record 4–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TDS 420A, TDS 430A & TDS 460A Service Manual

Table of Contents

Adjustment Procedures

Maintenance

Signal Acquisition System Checks 4–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Time Base System Checks 4–34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Trigger System Checks 4–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Output Signal Check 4–53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sine Wave Generator Leveling Procedure 4–55. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adjustment Procedures 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Requirements for Performance 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Usage 5–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Equipment Required 5–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adjustment Instructions 5–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Probe Adjustment 5–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Monitor Assembly Adjustment 5–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Maintenance 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Related Maintenance Procedures 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preparation 6–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Inspection and Cleaning 6–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Removal and Installation Procedures 6–9. . . . . . . . . . . . . . . . . . . . . . . . . .

Preparation — Please Read 6–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Access Procedure 6–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Procedures for Module Removal and Installation 6–23. . . . . . . . . . . . . . . . . . . . . . . .

Disassembly for Cleaning 6–65. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting 6–69. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagnostics 6–69. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Firmware Updates 6–70. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Troubleshooting Equipment 6–71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Options Electrical Parts List Diagrams Mechanical Parts List

TDS 420A, TDS 430A & TDS 460A Service Manual

List of Figures

Table of Contents

Figure 1–1: TDS 400A Dimensional Drawing 1–13. . . . . . . . . . . . . . . . . . . .

Figure 2–1: Map of Display Functions 2–8. . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–1: Map of Display Functions 4–3. . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–2: Verifying Adjustments and Signal Path Compensation 4–6.

Figure 4–3: Universal Test Hookup for Functional Tests 4–8. . . . . . . . . .

Figure 4–4: Initial Test Hookup 4–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–5: Initial Test Hookup 4–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–6: Initial Test Hookup 4–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–7: Measurement of Analog Bandwidth 4–29. . . . . . . . . . . . . . . . .

Figure 4–8: Initial Test Hookup 4–31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–9: Measurement of Channel Delay 4–33. . . . . . . . . . . . . . . . . . . .

Figure 4–10: Initial Test Hookup 4–34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–11: Measurement of Accuracy — Long-Term and

Delay-Time 4–37. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–12: Initial Test Hookup 4–38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–13: Initial Test Hookup 4–41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–14: Measurement of Trigger Sensitivity 4–43. . . . . . . . . . . . . . . .

Figure 4–15: Initial Test Hookup 4–45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–16: Confirming Auxiliary Triggering at Maximum

Triggering Frequency 4–46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–17: Initial Test Hookup 4–47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–18: Adjusting Sync Pulse Amplitude 4–49. . . . . . . . . . . . . . . . . . .

Figure 4–19: Measurement of Video Sensitivity 4–50. . . . . . . . . . . . . . . . . .

Figure 4–20: Initial Test Hookup 4–52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–21: Initial Test Hookup 4–54. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 4–22: Measurement of Probe Compensator Limits 4–55. . . . . . . . .

Figure 4–23: Sine Wave Generator Leveling Equipment Setup 4–56. . . . .

Figure 4–24: Equipment Setup for maximum Amplitude 4–57. . . . . . . . . .

Figure 5–1: Hookup for Probe Compensation 5–10. . . . . . . . . . . . . . . . . . .

Figure 5–2: Performing Probe Compensation 5–11. . . . . . . . . . . . . . . . . . .

Figure 5–3: Proper and Improper Probe Compensation 5–12. . . . . . . . . . .

Figure 5–4: Exposing the Inner Probe Tip 5–13. . . . . . . . . . . . . . . . . . . . . .

Figure 5–5: Initial Test Hookup 5–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Table of Contents

Figure 5–6: Exposing the Probe Body 5–16. . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–7: Initial Test Hookup 5–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–8: Probe Test Hookup 5–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 5–9: Locations of Probe Adjustments 5–19. . . . . . . . . . . . . . . . . . . .

Figure 5–10: Adjustments vs. Front-Corner Response 5–20. . . . . . . . . . . .

Figure 5–11: Monitor Adjustment Locations 5–23. . . . . . . . . . . . . . . . . . . .

Figure 5–12: Five and Ten Percent Luminance Patches 5–24. . . . . . . . . . .

Figure 5–13: Composite Pattern for Focusing 5–25. . . . . . . . . . . . . . . . . . .

Figure 6–1: Oscilloscope Orientation 6–11. . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–2: Cabinet and Front-Panel Mounted Modules 6–16. . . . . . . . . .

Figure 6–3: Internal Modules 6–19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–4: Cables and Cable Routing 6–22. . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–5: Knob and Shaft Removal 6–24. . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–6: Line Fuse and Line Cord Removal 6–25. . . . . . . . . . . . . . . . . .

Figure 6–7: Front Cover, Rear Cover, Cabinet, EMI Gasket, and

Cabinet Handle and Feet Removal 6–27. . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–8: Trim Ring, Menu Elastomer, and Menu Buttons

Removal 6–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–9: EMI Gasket Removal and Installation 6–32. . . . . . . . . . . . . . .

Figure 6–10: Disk Drive Removal 6–33. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–11: A06 Front-Panel Assembly, ESD Shield, and Menu

Flex and Probe Code Flex Circuits Removal 6–35. . . . . . . . . . . . . . . . .

Figure 6–12: Disassembly of the Front-Panel Assembly 6–36. . . . . . . . . . .

Figure 6–13: A05 Attenuator Removal 6–39. . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–14: A26 Monitor Assembly Removal 6–42. . . . . . . . . . . . . . . . . . .

Figure 6–15: A08 Jumper Board Assembly, D1 Bus, and Board

Supports Removal 6–43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–16: A03 CPU Removal 6–45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–17: A02 Display Assembly Removal 6–47. . . . . . . . . . . . . . . . . . .

Figure 6–18: A09 DSP Assembly Removal 6–48. . . . . . . . . . . . . . . . . . . . . .

Figure 6–19: A01 Backplane Assembly and its Mount Removal 6–50. . . .

Figure 6–20: Battery Removal 6–53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–21: A25 Low Voltage Power Supply Removal 6–55. . . . . . . . . . .

Figure 6–22: Fan and Fan Mount Removal 6–58. . . . . . . . . . . . . . . . . . . . .

Figure 6–23: Line Filter Removal 6–59. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–24: Auxiliary Power Supply Removal 6–62. . . . . . . . . . . . . . . . . .

Figure 6–25: A04 Acquisition Board Removal 6–64. . . . . . . . . . . . . . . . . . .

Figure 6–26: Accessing the Protection Switch 6–70. . . . . . . . . . . . . . . . . . .

TDS 420A, TDS 430A & TDS 460A Service Manual

Table of Contents

Figure 6–27: Console Port Connections 6–73. . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–28: Primary Troubleshooting Procedure 6–74. . . . . . . . . . . . . . .

Figure 6–29: A03 CPU Board Connector P1 6–75. . . . . . . . . . . . . . . . . . . .

Figure 6–30: Module Isolation Troubleshooting Procedure 6–76. . . . . . . .

Figure 6–31: Low Voltage Power Supply Troubleshooting Procedure 6–78 Figure 6–32: Power Supply Overload Troubleshooting Procedure 6–80. . Figure 6–33: A25 Low Voltage Power Supply Module (Right Side) 6–81. .

Figure 6–34: Monitor Troubleshooting Procedure 6–82. . . . . . . . . . . . . . . .

Figure 6–35: Horizontal and Vertical Sync Signals 6–83. . . . . . . . . . . . . . .

Figure 6–36: A Video Signal with White, Black, and Blanking Levels 6–83

Figure 6–37: A26 Monitor Connector J440 6–84. . . . . . . . . . . . . . . . . . . . . .

Figure 6–38: A07 Auxiliary Power Connectors J4 and J7 6–84. . . . . . . . . .

Figure 6–39: A02 Display Connector J2 6–85. . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–40: Processor/Front Panel Troubleshooting Procedure 6–86. . . .

Figure 6–41: A06 Front Panel Board Power Connectors J101

and J106 6–87. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–42: Attenuator/Acquisition Troubleshooting Procedure 6–88. . . Figure 6–43: A08 Jumper and A05 Attenuator Boards Signal

Locations 6–89. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–44: Acquisition and Attenuator Power Troubleshooting

Procedure 6–90. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–45: A04 Acquisition Board Power Connector 6–91. . . . . . . . . . . .

Figure 6–46: Backplane Troubleshooting Procedure 6–92. . . . . . . . . . . . . .

Figure 6–47: A01 Backplane Module 6–94. . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 6–48: I2C Isolation Troubleshooting Procedure 6–95. . . . . . . . . . . .

Figure 6–49: Console Troubleshooting Procedure 6–96. . . . . . . . . . . . . . . .

Figure 9–1: TDS 400A Interconnections 9–2. . . . . . . . . . . . . . . . . . . . . . . .

Figure 9–1: TDS 400A Interconnections (Cont.) 9–3. . . . . . . . . . . . . . . . .

Figure 9–2: TDS 400A Block Diagram 9–4. . . . . . . . . . . . . . . . . . . . . . . . .

Figure 9–2: TDS 400A Block Diagram (Cont.) 9–5. . . . . . . . . . . . . . . . . . .

Figure 10–1: External and Front Panel Modules 10–7. . . . . . . . . . . . . . . . .

Figure 10–2: Internal Modules 10–9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 10–3: Cables and Routing 10–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TDS 420A, TDS 430A & TDS 460A Service Manual

Table of Contents

List of Tables

Table 1–1: Key Features of the TDS 400A Oscilloscopes 1–1. . . . . . . . . .

Table 1–2: Record Length vs. Divisions per Record 1–3. . . . . . . . . . . . . .

Table 1–3: Nominal Traits — Signal Acquisition System 1–7. . . . . . . . . .

Table 1–4: Nominal Traits — Time Base System 1–9. . . . . . . . . . . . . . . .

Table 1–5: Nominal Traits — Triggering System 1–9. . . . . . . . . . . . . . . .

Table 1–6: Nominal Traits — Display System 1–10. . . . . . . . . . . . . . . . . . .

Table 1–7: Nominal Traits — Data Storage 1–10. . . . . . . . . . . . . . . . . . . . .

Table 1–8: Nominal Traits — GPIB Interface, Video Output, and

Power Fuse 1–10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–9: Nominal Traits — Mechanical 1–11. . . . . . . . . . . . . . . . . . . . . .

Table 1–10: Warranted Characteristics — Signal Acquisition

System 1–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–11: Warranted Characteristics — Time Base System 1–17. . . . . .

Table 1–12: Warranted Characteristics — Triggering System 1–18. . . . .

Table 1–13: Warranted Characteristics — Probe Compensator

Output 1–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–14: Warranted Characteristics — Power Requirements 1–18. . . Table 1–15: Warranted Characteristics — Environmental, Safety,

and Reliability 1–19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 1–16: Certifications and compliances 1–20. . . . . . . . . . . . . . . . . . . . .

Table 1–17: Typical Characteristics — Signal Acquisition System 1–21. .

Table 1–18: Typical Characteristics — Time Base System 1–22. . . . . . . . .

Table 1–19: Typical Characteristics — Triggering System 1–23. . . . . . . .

Table 1–20: Typical Characteristics — Data Handling 1–24. . . . . . . . . . .

Table 2–1: Power-Cord Conductor Identification 2–2. . . . . . . . . . . . . . . .

Table 2–2: Power Cord Identification 2–2. . . . . . . . . . . . . . . . . . . . . . . . .

Table 2–3: Effects of Corrupted Data 2–4. . . . . . . . . . . . . . . . . . . . . . . . . .

Table 4–1: Test Equipment 4–16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 4–2: DC Offset Accuracy 4–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 4–3: Analog Bandwidth (TDS 420A) 4–27. . . . . . . . . . . . . . . . . . . . .

Table 4–4: Analog Bandwidth (TDS 430A and TDS 460A) 4–28. . . . . . . .

Table 5–1: Adjustments Required for Module Replaced 5–3. . . . . . . . . .

Table 5–2: Adjustments and Dependencies 5–4. . . . . . . . . . . . . . . . . . . . .

Table 5–3: Test Equipment, Fixtures, and Supplies 5–5. . . . . . . . . . . . . .

TDS 420A, TDS 430A & TDS 460A Service Manual

Table of Contents

Table 5–4: GPIB Board Configuration1 5–7. . . . . . . . . . . . . . . . . . . . . . . .

Table 6–1: Relative Susceptibility to Static-Discharge Damage 6–3. . . . .

Table 6–2: External Inspection Check List 6–5. . . . . . . . . . . . . . . . . . . . .

Table 6–3: Internal Inspection Check List 6–6. . . . . . . . . . . . . . . . . . . . . .

Table 6–4: Tools Required for Module Removal 6–12. . . . . . . . . . . . . . . . .

Table 6–5: Access Instructions for Modules in Figure 6–2 6–15. . . . . . . . .

Table 6–6: Access Instructions for Modules in Figure 6–3 6–17. . . . . . . . .

Table 6–7: Access (and Removal) Instructions for Cables in

Figure 6–4 6–20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 6–8: Troubleshooting Test Equipment, Fixtures, and

Supplies 6–71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 6–9: Connections for a 9 to 25 Pin Null Modem Cable 6–72. . . . . .

Table 6–10: Diagnostic Failure Priority Lists 6–77. . . . . . . . . . . . . . . . . . .

Table 6–11: Normal Output Voltage 6–79. . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 6–12: Power Supply Maximum Current 6–81. . . . . . . . . . . . . . . . . .

Table 6–13: Front Panel Connector Voltages 6–87. . . . . . . . . . . . . . . . . . . .

Table 6–14: Channel and P1 Signal Locations 6–89. . . . . . . . . . . . . . . . . . .

Table 6–15: A05 Attenuator Board Power 6–90. . . . . . . . . . . . . . . . . . . . . .

Table 6–16: A04 Acquisition Board Power 6–91. . . . . . . . . . . . . . . . . . . . . .

Table 6–17: Regulator Voltages 6–93. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 6–18: J7 Voltages 6–93. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 6–19: J8 Front Panel Voltages 6–93. . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 7–1: International Power Cords 7–2. . . . . . . . . . . . . . . . . . . . . . . . .

Table 7–2: Standard Accessories 7–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 7–3: Optional Accessories 7–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 7–4: Compatible Probes 7–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table 7–5: Accessory Software 7–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TDS 420A, TDS 430A & TDS 460A Service Manual

vii

Table of Contents

viii

TDS 420A, TDS 430A & TDS 460A Service Manual

General Safety Summary

Review the following safety precautions to avoid injury and prevent damage to this product or any products connected to it.

To avoid potential hazards, use this product only as specified.

Only qualified personnel should perform service procedures.

Injury Precautions

Use Proper Power Cord. To avoid fire hazard, use only the power cord specified

for this product. Avoid Electric Overload. To avoid electric shock or fire hazard, do not apply a

voltage to a terminal that is outside the range specified for that terminal. Avoid Electric Shock. To avoid injury or loss of life, do not connect or disconnect

probes or test leads while they are connected to a voltage source. Ground the Product. This product is grounded through the grounding conductor

of the power cord. To avoid electric shock, the grounding conductor must be connected to earth ground. Before making connections to the input or output terminals of the product, ensure that the product is properly grounded.

Do Not Operate Without Covers. To avoid electric shock or fire hazard, do not operate this product with covers or panels removed.

Use Proper Fuse. To avoid fire hazard, use only the fuse type and rating specified for this product.

Do Not Operate in Wet/Damp Conditions. To avoid electric shock, do not operate this product in wet or damp conditions.

Do Not Operate in an Explosive Atmosphere. To avoid injury or fire hazard, do not operate this product in an explosive atmosphere.

Product Damage

Precautions

TDS 420A, TDS 430A & TDS 460A Service Manual

Use Proper Power Source. Do not operate this product from a power source that applies more than the voltage specified.

Provide Proper Ventilation. To prevent product overheating, provide proper ventilation.

Do Not Operate With Suspected Failures. If you suspect there is damage to this product, have it inspected by qualified service personnel.

General Safety Summary

Symbols and Terms

T erms in this Manual. These terms may appear in this manual:

WARNING. Warning statements identify conditions or practices that could result in injury or loss of life.

CAUTION. Caution statements identify conditions or practices that could result in damage to this product or other property.

T erms on the Product. These terms may appear on the product: DANGER indicates an injury hazard immediately accessible as you read the

marking. WARNING indicates an injury hazard not immediately accessible as you read the

marking. CAUTION indicates a hazard to property including the product.

Symbols on the Product. The following symbols may appear on the product:

Certifications and

Compliances

DANGER

High Voltage

Protective Ground

(Earth) T erminal

ATTENTION

Refer to Manual

Double

Insulated

Refer to the specifications section for a listing of certifications and compliances that apply to this product.

TDS 420A, TDS 430A & TDS 460A Service Manual

Service Safety Summary

Only qualified personnel should perform service procedures. Read this Service Safety Summary and the General Safety Summary before performing any service

procedures. Do Not Service Alone. Do not perform internal service or adjustments of this

product unless another person capable of rendering first aid and resuscitation is present.

Disconnect Power. To avoid electric shock, disconnect the main power by means of the power cord or, if provided, the power switch.

Use Caution When Servicing the CRT. To avoid electric shock or injury, use extreme caution when handling the CRT. Only qualified personnel familiar with CRT servicing procedures and precautions should remove or install the CRT.

CRTs retain hazardous voltages for long periods of time after power is turned off. Before attempting any servicing, discharge the CRT by shorting the anode to chassis ground. When discharging the CRT, connect the discharge path to ground and then the anode. Rough handling may cause the CRT to implode. Do not nick or scratch the glass or subject it to undue pressure when removing or installing it. When handling the CRT, wear safety goggles and heavy gloves for protection.

Use Care When Servicing With Power On. Dangerous voltages or currents may exist in this product. Disconnect power, remove battery (if applicable), and disconnect test leads before removing protective panels, soldering, or replacing components.

To avoid electric shock, do not touch exposed connections. X-Radiation. To avoid x-radiation exposure, do not modify or otherwise alter the

high-voltage circuitry or the CRT enclosure. X-ray emissions generated within this product have been sufficiently shielded.

TDS 420A, TDS 430A & TDS 460A Service Manual

Service Safety Summary

xii

TDS 420A, TDS 430A & TDS 460A Service Manual

Preface

Manual Structure

This service manual provides service information for the TDS 420A, TDS 430A, and TDS 460A Digitizing Oscilloscopes.

STOP. If servicing a TDS 430A, follow the procedures for the TDS 460A, but ignore all references to CH 3 and CH 4.

This manual is divided into Chapters such as Specifications and Theory of Operation. Further, it is divided into subsections such as Product Description

and Removal and Installation Procedures. Sections containing procedures also contain introductions to those procedures.

Be sure to read these introductions because they provide information needed to do the service correctly and efficiently. A brief description of each manual chapter follows:

 Specifications contains a product description of the digitizing oscilloscope

and tables of the characteristics and descriptions that apply to it.  Operating Information is this chapter. It includes a description of how this

manual is structured as well as general information and operating instruc-

tions at the level needed to safely power on and service this oscilloscope. A

statement of the service strategy that this manual supports and instructions

for shipment of the digitizing oscilloscope are found in this chapter.  Theory of Operation contains circuit descriptions that support general service

and fault isolation.  Performance Verification contains a collection of procedures for confirming

that this digitizing oscilloscope functions properly and meets warranted

limits.  Adjustment Procedures contains a collection of procedures for adjusting this

digitizing oscilloscope to meet warranted limits.  Maintenance contains information and procedures for doing preventive and

corrective maintenance of the digitizing oscilloscope. Instructions for

cleaning, for module removal and installation, and for fault isolation to a

module are found here.

TDS 420A, TDS 430A & TDS 460A Service Manual

xiii

Preface

Manual Conventions

 Options contains information on the factory-installed options that may be

present in your oscilloscope.

 Electrical Parts List contains a statement referring you to the Mechanical

Parts List, where both electrical and mechanical modules are listed. See below.

 Diagrams contains a block diagram and an interconnection diagram useful

for isolating failed modules.

 Mechanical Parts List includes a table of all replaceable modules, their

descriptions, and their Tektronix part numbers.

This manual uses certain conventions which you should become familiar with before doing service.

Modules

Safety

Symbols

Throughout this manual, any replaceable component, assembly, or part of this digitizing oscilloscope is referred to generically as a module. In general, a module is an assembly, like a circuit board, rather than a component, like a resistor or an integrated circuit. Sometimes a single component is a module; for example, the chassis of the oscilloscope is a module.

Symbols and terms related to safety appear in the General Safety Summary and Service Safety Summary found at the beginning of this manual.

Besides the symbols related to safety, this manual uses the following symbols:

STOP. This “stop sign” labels information which you must read in order to correctly do service and to avoid incorrectly using or applying service procedures.

The clock icon labels procedure steps which require a pause to wait for the oscilloscope to complete some operation before you can continue.

Various icons such as the example icon at the left are used in procedures to help identify certain readouts and menu functions on screen.

xiv

TDS 420A, TDS 430A & TDS 460A Service Manual

Related Manuals

Preface

These other manuals are available for the TDS 430A, TDS 420A, and TDS 460A Digitizing Oscilloscopes:

 The Reference gives you a quick overview of how to operate your oscillo-

scope.

 The User Manual provides instructions on how to operate your oscilloscope.  The Programmer Manual provides complete information on programming

and remote control of the oscilloscope through the GPIB.

TDS 420A, TDS 430A & TDS 460A Service Manual

Introduction

Before Servicing

This section contains general information critical to safe and effective servicing of this oscilloscope, the manual service strategy, and a description of repair and warranty services available from Tektronix.

This manual is for servicing the TDS 420A, TDS 430A, & TDS 460A Digitizing Oscilloscopes. To prevent injury to yourself or damage to the oscilloscope, do the following before you attempt service:

 Be sure you are a qualified service person.  Read the safety summaries found at the beginning of this manual.  Read Strategy for Servicing and Supplying Operating Power in

this subsection.

When using this manual for servicing, be sure to heed all warnings, cautions, and notes.

Strategy for Servicing

STOP. If servicing a TDS 430A, follow the procedures for the TDS 420A, but ignore all references to CH 3 and CH 4.

STOP. Throughout this manual, any field-replaceable component, assembly, or part of this oscilloscope is referred to generically as a module.

This manual contains all the information needed for periodic maintenance of your oscilloscope. (Examples of such information are procedures for checking performance and for readjustment.) Further, it contains all information for corrective maintenance down to the module level. This means that the procedures, diagrams, and other troubleshooting aids help isolate failures to a specific module, rather than to components of that module. Once a failure is isolated, replace the module with a fully tested module obtained from the factory.

All modules are listed in Chapter 10, Mechanical Parts List. To isolate a failure to a module, use the fault isolation procedures found in Chapter 6, Maintenance.

xvi

TDS 420A, TDS 430A & TDS 460A Service Manual

Tektronix Service

Introduction

To remove and replace any failed module, follow the instructions in Removal and Installation Procedures, also found in Chapter 6.

Tektronix provides service to cover repair under warranty as well as other services that may provide a cost-effective answer to your service needs.

Whether providing warranty repair service or any of the other services listed below, Tektronix service technicians, trained on Tektronix products, are best equipped to service your digitizing oscilloscope. Tektronix technicians are appraised of the latest information on improvements to the product as well as the latest new options to the product.

Warranty Repair Service

Repair or Calibration

Service

Tektronix warrants this product for three years from date of purchase, excluding probes for which the warranty is one year. (The warranty appears on the back of the title page in this manual.) Tektronix technicians provide warranty service at most Tektronix service locations worldwide. Your Tektronix product catalog lists all service locations worldwide.

The following services may be purchased to tailor repair and/or calibration of your digitizing oscilloscope to fit your requirements.

Option 95. With this option, Tektronix ships a test data report for the oscilloscope.

At-Depot Service. Tektronix offers several standard-priced adjustment (calibration) and repair services:

 A single repair or adjustment  Calibrations using equipment and procedures that meet the traceability

standards specific to the local area  Annual maintenance agreements that provide for either calibration and repair

or calibration only of the oscilloscope Of these services, the annual maintenance agreement offers a particularly

cost-effective approach to service for many owners of the TDS 400A Digitizing Oscilloscopes. You can purchase such agreements to span several years.

Self Service

TDS 420A, TDS 430A & TDS 460A Service Manual

Tektronix supports repair to the module level by providing Module Exchange and Module Repair and Return.

xvii

Introduction

Module Exchange. This service reduces down time for repair by allowing you to exchange most modules for remanufactured ones. Tektronix ships you an updated and tested exchange module from the Beaverton, Oregon service center, typically within 24 hours. Each module comes with a 90-day service warranty.

For More Information. Contact your local Tektronix service center or sales engineer for more information on any of the repair or adjustment services just described.

xviii

TDS 420A, TDS 430A & TDS 460A Service Manual

Product Description

This Chapter begins with a general description of the traits of the TDS 400A Digitizing Oscilloscopes. Three sections follow, one for each of three classes of traits: nominal traits, warranted characteristics, and typical characteristics.

General

The TDS 400A Digitizing Oscilloscopes are portable, four-channel instruments suitable for use in a variety of test and measurement applications and systems. Table 1–1 lists key features.

T able 1–1: Key Features of the TDS 400A Oscilloscopes

Feature Description

Digitizing rate, maximum 100 MS/s on each channel simultaneously Analog bandwidth TDS 460A: 400 MHz

TDS 420A: 200 MHz TDS 430A: 400 MHz

Channels TDS 460A: Four, each with 8-bit resolution

TDS 420A: Four, each with 8-bit resolution

TDS 430A: Two, each with 8-bit resolution Record lengths, maximum 30,000 samples (120,000 with option 1M) Acquisition modes Sample, envelope, average, high-resolution, and peak-detect Trigger modes Edge

With Option 05, video trigger modes include:

NTSC, SECAM, PAL, and Custom Display Modes Infinite and variable persistence, roll, fit to screen, and dual

waveform zoom Storage A 1.44 Mbyte, 3.5 inch, DOS 3.3-or-later floppy disk and

NVRAM storage for saving waveforms, hardcopies, and setups I/O Full GPIB programmability

Hardcopy output using GPIB and, with Option 13, RS-232 or

Centronics ports Math Including: invert, add, subtract, multiply, and with Option 2F,

integral, differential, and FFT User interface A graphical user interface, on-line help. and a logical

front-panel layout

TDS 420A, TDS 430A & TDS 460A Service Manual

1–1

Product Description

User Interface

This digitizing oscilloscope uses a combination of front-panel buttons, knobs, and on-screen menus to control its many functions. The front-panel controls are grouped according to function: vertical, horizontal, trigger, and special. Within each group, any function likely to get adjusted often, such as vertical positioning or the time base setting, is set directly by its own front-panel knob.

Menus

Indicators

General Purpose Knob

Those functions for which control settings are usually changed less often, such as vertical coupling and horizontal mode, are set indirectly. That is, pressing one (sometimes two) front-panel button, such as VERTICAL, displays a menu of functions at the bottom of the screen that are related to that button. (For the VERTICAL button, the menu displayed contains functions such as coupling and bandwidth.) Using the buttons below this main menu to select a function, such as coupling, displays a side menu of settings for that function, such as AC, DC, or GND (ground) coupling, at the right side of the screen. Use the buttons to the right of the menu to select a setting, such as DC.

Several on-screen readouts help you keep track of the settings for various functions, such as vertical and horizontal scale and trigger level. There are also readouts to display the results of measurements made using cursors or using the automatic parameter extraction feature (called measure) and readouts to display the status of the oscilloscope.

Menus are also used to assign the general purpose knob to adjust a selected parameter function. The method employed is the same as for selecting a function, except the final selection in the side menu causes the general purpose knob to adjust some function, such as the position of measurement cursors on screen or the setting for the fine gain of a channel.

1–2

GUI

The user interface also makes use of a GUI, or Graphical User Interface, to make setting functions and interpreting the display more intuitive. Some menus and status are displayed using iconic representations of function settings such as those shown here for full, 100 MHz, and 20 MHz bandwidth. Such icons allow you to more readily determine status or the available settings.

TDS 420A, TDS 430A & TDS 460A Service Manual

Signal Acquisition System

The signal acquisition system provides vertical channels with calibrated vertical scale factors from 1 mV to 10 V per division. All input channels can be acquired simultaneously.

You can display, vertically position, and offset each input channel. You can also limit their bandwidth (to either 100 MHz or 20 MHz), specify their vertical coupling, and adjust their fine gain.

Besides the input channels, up to three math waveforms and four reference waveforms are available for display. (A math waveform results when you specify operations such as add or invert; a reference waveform results when you save a live waveform in a reference memory.)

Horizontal System

There are three horizontal display modes: main only, main intensified, and delayed only. You can select among various horizontal record length settings (see Table 1–2).

Product Description

T able 1–2: Record Length vs. Divisions per Record

Record Length

120,000 2400 divs 60,000 1200 divs 30,000 600 divs 15,000 300 divs 5,000 100 divs 2,500 50 divs 1,000 20 divs 500 10 divs

The 60,000 and 120,000 point record lengths are available only with Option 1M.

If you select the Hi Res acquisition mode, the maximum Option 1M record length reduces to 60,000 points.

1, 2

Divisions per Record (50 Points/Division)

TDS 420A, TDS 430A & TDS 460A Service Manual

1–3

Product Description

Trigger System

Both the delayed only display and the intensified zone on the main intensified display can be delayed by time with respect to the main trigger. You can set both to display immediately after the delay (delayed runs after main mode); you can set the delayed display to display at the first valid trigger after the delay (delayed triggerable mode).

The delayed display (or the intensified zone) can also be delayed by a selected number of events. In such a case, the events source is the delayed trigger source. For any events signal, the delayed-trigger system conditions the signal by determining the source, coupling, and other things, of that signal.

At time base settings of 20 ms per division or slower the records are displayable using Roll mode. Both untriggered roll and triggered roll modes are available.

The triggering system comprises a complete set of features for triggering the signal-acquisition system. In edge trigger mode, you can select the source, slope, coupling, mode (auto or normal), and holdoff.

Acquisition Control

Oscilloscopes ordered with Option 5 also have the video trigger mode. This trigger mode allows triggering on NTSC-standard, PAL-standard, SECAM-standard, and custom video waveforms. You can configure the triggering for interlaced or non-interlaced scanning, different scan rates, field selection, line selection, and for delay by line or time.

You can choose where the trigger point is located within the acquired waveform record by selecting the amount of pretrigger data displayed. You can select presets of 10%, 50%, and 90% of pretrigger data in the horizontal menu, or you can assign the General Purpose knob to set pretrigger data to any value within the limits of trigger position resolution.

Depending on your measurement requirements, you can specify the mode and manner in which signals are acquired and processed:

 You can select equivalent-time sampling on repetitive signals or interpola-

tion of points sampled on non-repetitive signals. Both can increase the apparent sample rate on the waveform when maximum real-time rates are reached.

 You can use peak-detect, high-resolution, sample, envelope, and average

modes to acquire signals.

1–4

 You can set the acquisition to stop after a single acquisition (or sequence of

acquisitions if acquiring in average or envelope modes).

TDS 420A, TDS 430A & TDS 460A Service Manual

On-Board User Assistance

Two features that help you set up this digitizing oscilloscope to make your measurements are help and autoset.

Product Description

Help

Autoset

Help displays operational information about any front-panel control. When help mode is in effect, manipulating any front-panel control causes the digitizing oscilloscope to display information about that control. When help is first invoked, an introduction to help is displayed on screen.

Autoset automatically sets up the digitizing oscilloscope for a viewable display based on the input signal.

Measurement Assistance

Once you have set up to make your measurements, the features cursor and measure can help you quickly make those measurements.

Cursor

Two types of cursors are provided for making parametric measurements on the displayed waveforms. Voltage can be measured between the positions of H Bar (horizontal) cursors, and time can be measured between V Bar (vertical) cursors. These are delta measurements; that is, measurements based on the difference between two cursors.

You can use both V Bar and H Bar cursors to make absolute measurements— measurements relative to a defined level or event. In the case of the H Bars, either cursor can be selected to read out its voltage with respect to the ground reference level of any channel; in the case of the V Bars, its time with respect to the trigger point (event) of the acquisition.

For time measurements, units can be either base (seconds or clocks) or inverse base (Hertz or 1/clocks).

Measure

TDS 420A, TDS 430A & TDS 460A Service Manual

Measure can automatically extract parameters from the signal input to the digitizing oscilloscope. Any four out of the more than 20 parameters available can be displayed on the screen. The displayed parameters are extracted continuously and the results updated on screen as the digitizing oscilloscope continues to acquire waveforms.

1–5

Product Description

Storage

I/O

TDS 400A Digitizing Oscilloscopes can save acquired waveforms in any of four nonvolatile REF (reference) memories. You can save any input-channel waveform to any REF memory, or you can move a stored reference from one REF memory to another. You can display any or all of the saved waveforms for comparison with the waveforms being currently acquired.

TDS 400A Digitizing Oscilloscopes are fully controllable and capable of sending and receiving waveforms over the GPIB interface (IEEE Std 488.1-1987/IEEE Std 488.2-1987 standard). Self-compensation and self-diagnostic features built into the digitizing oscilloscope to aid in fault detection and servicing are also accessible using commands sent from a GPIB controller. The oscilloscope also provides the following output capabilities:

 Output of the current oscilloscope screen, including waveforms, to a variety

of graphic printers and plotters to obtain hard copies. You can start a hardcopy from the oscilloscope front panel; you are not required to connect into a system-controller environment. The hard copies obtained are WYSIWYG (What-You-See-Is-What-You-Get), based on what is displayed at the time hardcopy is invoked.

Display

 Output of display hard copies, of oscilloscope control setups, and of

waveforms to a floppy disk in the oscilloscope file system.

 Output of the oscilloscope display for monitoring (or other processing) from

a VGA-compatible video output on the oscilloscope rear panel.

The TDS 400A Digitizing Oscilloscopes offer flexible display options. You can customize the following attributes of your display:

 Intensity: waveforms, readouts, graticule, and other things  Style of waveform display(s): vectors or dots, intensified or non-intensified

samples, and infinite or variable persistence

 Display format: XY or YT and graticule type This digitizing oscilloscope also provides an easy way to focus in on those

waveform features you wish to examine up close. By using ZOOM, you can magnify the waveform parameter using the vertical and horizontal controls to expand (or contract) and position it for viewing.

1–6

TDS 420A, TDS 430A & TDS 460A Service Manual

Nominal Traits

set, All C

els

Nominal traits are described using simple statements of fact such as “Four, all identical” for the trait “Input Channels, Number of,” rather than in terms of limits that are performance requirements.

T able 1–3: Nominal Traits — Signal Acquisition System

Name Description

Bandwidth Selections 20 MHz, 100 MHz, and FULL (TDS 420A: 200 MHz, TDS 430A and

TDS 460A: 400 MHz)

Digitizers, Number of TDS 430A: Two, both identical

TDS 420A and TDS 460A: Four, all identical Digitized Bits, Number of 8 bits Digitized Resolution, Hi Res Mode Clock, Internal:

Resolution

Clock, External:

Resolution

 8 8 0.5 Log

HiRes

 8 8 0.5 Log

HiRes

timediv



500  10



ClockExternalMenu



–9

100,000,000



 15 bits





 11.8 bits

Bandwidth, Hi Res Mode Clock, Internal:

For 1sdiv and slower, BW

Clock, External:

ClockExternalMenu

Input Channels, Number of TDS 430A: Two, both identical, called CH 1 and CH 2

TDS 420A and TDS 460A: Four, all identical, called CH 1 through CH 4 Input Coupling DC, AC, or GND Input Resistance Selections

Ranges, Off

Range, Position ±5 divisions Range, Sensitivity

hann

1 M or 50

Volts/Div Setting Offset Range

1 mV/div to 99.5 mV/div ±1 V

100 mV/div to 995 mV/div ±10 V

1 V/div to 10 V/div ±100 V

1 mV/div to 10 V/div

HiRes

 44 



100

HiRes

 0.44





timediv



TDS 420A, TDS 430A & TDS 460A Service Manual

1–7

Nominal Traits

ise Time

T able 1–3: Nominal Traits — Signal Acquisition System (Cont.)

Name Description

R (TDS420A)

R (TDS 430A and TDS 460A)

Volts/Div Setting Rise T ime

5 mV/div–10 V/div

1.75 ns 2 mV/div–4.98 mV/div 2.33 ns 1 mV/div–1.99 mV/div 3.68 ns

Volts/Div Setting Rise T ime

5 mV/div–10 V/div

875 ps 2 mV/div–4.98 mV/div 1.4 ns 1 mV/div–1.99 mV/div 3.5 ns

Displayed vertically with 25 digitization levels (DLs) per division and 10.24 divisions dynamic range with zoom off. A DL is the smallest voltage level change resolved by the 8-bit A-D Converter with the input scaled to the volts/division setting of the channel used. Expressed as a voltage, a DL is equal to 1/25 of a division times the volts/division setting.

GND input coupling disconnects the input connector from the attenuator and connects a ground reference to the input of the attenuator.

The sensitivity ranges from 1 mV/div to 10 V/div in a 1–2–5 sequence of coarse settings. Between consecutive coarse settings, the sensitivity can be finely adjusted with a resolution of 1% of the more sensitive setting. For example, between 50 mV/div and 100 mV/div, the volts/division can be set with 0.5 mV resolution.

Rise time is defined by the following formula:

Rise Time (ns) 

420

BW (MHz)

1–8

TDS 420A, TDS 430A & TDS 460A Service Manual

Nominal Traits

evel or

reshol

T able 1–4: Nominal Traits — Time Base System

Name Description

2,3

1,3

2.5 Samples/s to 100 MSamples/s 200 MSamples/s to 50 GSamples/s

120,000 points are available with Option 1M

to 2 ms. An external clock edge before this period ends produces an invalid sample.

Range, Sample-Rate Range, Equivalent Time or Interpolated

Waveform Rate Range, Seconds/Division 1 ns/div to 20 s/div Range, Time Base Delay Time 0 to 20 seconds Reference Frequency, Time Base 100 MHz Record Length Selection 500, 1,000, 2,500, 5,000, 15,000, and 30,000 points. Record lengths of 60,000 and

Sampling Edge, External Clock Negative edge, with TTL threshold and tolerances Hi Res Averaging Period, External Clock Hi Res averaging done over period 1/(maximum external clock rate5), but within <100 ns

The range of real-time rates, expressed in samples/second, at which a digitizer samples signals at its inputs and stores the samples in memory to produce a record of time-sequential samples.

The range of waveform rates for equivalent time or interpolated waveform records.

The Waveform Rate (WR) is the equivalent sample rate of a waveform record. For a waveform record acquired by real-time sampling of a single acquisition, the waveform rate is the same as the real-time sample rate; for a waveform created by interpolation of real-time samples from a single acquisition or by equivalent-time sampling of multiple acquisitions, the waveform rate is faster than the real time sample rate. For all three cases, the waveform rate is 1/(Waveform Interval) for the waveform record, where the waveform interval (WI) is the time between the samples in the waveform record.

In Hi Res, the maximum Option 1M record length is 60,000 points.

You set the maximum external clock rate using the Horizontal Clock menu. The Hi Res samples are averaged over a 10 to 40 ns shorter period than shown by the readout.

T able 1–5: Nominal Traits — Triggering System

Name Description

Range, Events Delay 1 to 9,999,999 Ranges, Trigger L

d Source Range

Any Channel ±12 divisions from center of screen Line ±400 Volts

TDS 420A, TDS 430A & TDS 460A Service Manual

1–9

Nominal Traits

T able 1–6: Nominal Traits — Display System

Name Description

Video Display Resolution 640 pixels horizontally by 480 pixels vertically in a display area of 5.04 inches horizontally

by 3.78 inches vertically

Waveform Display Graticule A single graticule 401 × 501 pixels (8 × 10 divisions, with divisions that are 1 cm by

1 cm)

Waveform Display Grey Scale 16 levels in variable-persistence display style

T able 1–7: Nominal Traits — Data Storage

Name Description

Capacity , Nonvolatile Waveform Memory Total capacity is 120,000 points (one to four waveforms acquired with any combination of

record lengths that add up to 120,000 points). For available record lengths, see Record Length Selection on page 1–9 of this chapter.

Capacity , Nonvolatile Setup Memory Ten setups Batteries1 Required Two lithium poly-carbon monofluoride. Both are type BR2/3A, UL listed. Both are rated at

3.0 volt, 1.2 amp-hour.

Batteries are not accessible from the outside of the instrument; therefore, a service technician must replace them.

T able 1–8: Nominal Traits — GPIB Interface, Video Output, and Power Fuse

Name Description

Interface, GPIB GPIB interface complies with IEEE Std 488.1-1987 and IEEE Std 488.2-1987. Interface, RS-232 (Option 13 only) RS-232 interface complies with EIA/TIA 574. Interface, Centronics (Option 13 only) Centronics interface complies with Centronics interface standard C332-44 Feb 1977,

REV A.

Power Supply , Printer (Option 13 only) Supply Voltage: +6.5 VDC

Maximum Current: 2 Amps, DC continuous

4 Amps DC maximum for durations < 10 msec

Output, Video Provides a video signal1, non-interlaced, with levels that comply with ANSI RS343A.

Output is through a rear-panel DB-15 connector.

Fuse Rating Either of two fuses2 may be used: a 0.25I × 1.25I (UL 198.6, 3AG): 5 A FAST, 250 V, or

a 5 mm × 20 mm, (IEC 127): 4 A (T), 250V.

VGA compatible at 30.6 kHz sync rate.

Each fuse type requires its own fuse cap.

1–10

TDS 420A, TDS 430A & TDS 460A Service Manual

Nominal Traits

T able 1–9: Nominal Traits — Mechanical

Name Description

Cooling Method Forced-air circulation with no air filter Construction Material Chassis parts constructed of aluminum alloy; front panel constructed of plastic laminate;

circuit boards constructed of glass-laminate. Plastic parts are polycarbonate. Finish Type Tektronix Blue textured vinyl finish on aluminum cabinet Weight Standard digitizing oscilloscope

8.6 kg (19.0 lbs), oscilloscope only

10.2 kg (22.5 lbs), with front cover, accessories, and accessories pouch installed

14.5 kg (32.0 lbs), when packaged for domestic shipment 225 grams (0.5 lbs) Floppy Disk Drive only

Rackmount digitizing oscilloscope

8.2 kg (18.0 lbs) plus the weight of rackmount parts, for the rackmounted digitizing oscilloscope (Option 1R)

16.3 kg (36.0 lbs), when the rackmounted digitizing oscilloscope is packaged for domestic shipment

Rackmount conversion kit

4.5 kg (10.0 lbs), parts only; 7.9 kg (17.5 lbs), parts plus package for domestic shipping

TDS 420A, TDS 430A & TDS 460A Service Manual

1–11

Nominal Traits

T able 1–9: Nominal Traits — Mechanical (Cont.)

Name Description

Overall Dimensions Standard digitizing oscilloscope

Height 191 mm (7.5 in), when feet and accessories pouch are installed. 165 mm

(6.5 in), without the accessories pouch installed Width 381 mm (15 in), with handle Depth 471 mm (18.55 in), oscilloscope only; 490 mm (19.28 in), with optional

front cover installed; 569 mm (22.4 in), with handle fully extended

Rackmount digitizing oscilloscope

Height 178 mm (7.0 in) Width 483 mm (19.0 in) Depth 472 mm (18.6 in), without front-panel handles; 517 mm (20.35 in), with

front-panel handles installed

1–12

TDS 420A, TDS 430A & TDS 460A Service Manual

Nominal Traits

308.1 mm

(12.13 in.)

471 mm

(18.55 in.)

327.2 mm (12.88 in.)

165 mm

(6.5 in.)

569 mm

(22.4 in.)

Figure 1–1: TDS 400A Dimensional Drawing

TDS 420A, TDS 430A & TDS 460A Service Manual

381 mm

(15 in.)

1–13

Nominal Traits

1–14

TDS 420A, TDS 430A & TDS 460A Service Manual

W arranted Characteristics

Accuracy, D

age Mea-

urement, Averaged

Accuracy, O

This section lists the various warranted characteristics that describe the TDS 400A Digitizing Oscilloscopes. Included are electrical and environmental characteristics.

Warranted characteristics are described in terms of quantifiable performance limits which are warranted. This section lists only warranted characteristics. A list of typical characteristics starts on page 1–21.

NOTE. In these tables, those warranted characteristics that are checked in the procedure Performance Tests, on page 4–15, appear in boldface type under the column Name.

Performance Conditions

The electrical characteristics found in these tables of warranted characteristics apply when the oscilloscope is adjusted at an ambient temperature between +20_ C and +30_ C, has had a warm-up period of at least 20 minutes, and is operating at an ambient temperature between 0_ C and +50_ C (unless otherwise noted).

T able 1–10: Warranted Characteristics — Signal Acquisition System

TDS 420A, TDS 430A & TDS 460A Service Manual

Name Description

C Volt

Accuracy, DC Gain

ffset Volts/Div Setting Offset Accuracy

Accuracy , Position

Measurement Type DC Accuracy

Average of ≥16 waveforms ±(1.5% × |(reading – Net Offset1)| + Offset Accuracy +

Delta volts between any two averages of≥16 waveforms

±1.5%

1 mV/div–9.95 mV/div ±(0.4%× |Net Offset1| + ( 0.9 mV + 0.1 div × Vertical Scale)) 10 mV/div–99.5 mV/div ±(0.4% × |Net Offset1| + (1.5 mV + 0.1 div × Vertical Scale)) 100 mV/div–995 mV/div ±(0.4% × |Net Offset1| + ( 15 mV + 0.1 div × Vertical Scale)) 1 V/div–10 V/div ±(0.4% × |Net Offset1| + (150 mV + 0.1 div × Vertical Scale) ±(1.5% × (Position × Volts/div) + Offset Accuracy + 0.04 div)

0.06 div × Vertical Scale) ±(1.5% × |reading| + 0.3 mV + 0.1 div ×Vertical Scale)

1–15

Warranted Characteristics

Analog Bandwidth, DC-

Selecti

ull

Cross

Isolatio

oltage

T able 1–10: Warranted Characteristics — Signal Acquisition System (Cont.)

Name Description

50  Coupled to BNC and Bandwidth

Delay Between Channels, Full Bandwidth, Equivalent Time

Input Impedance, DC-1 M Coupled

Input Impedance, DC-50  Coupled (TDS 420A)

Input Impedance, DC-50  Coupled (TDS 430A and TDS 460A)

nput V DC-1 M, AC-1 M, or GND Coupled

Input Voltage, Maximum, DC-50  or AC-50  Coupled

on is F

Talk (Channel

, Maximum,

n) Volts/Div Isolation

TDS 420A

Volts/Div

5 mV/div–10 V/div DC–200 MHz DC–400 MHz 2 mV/div–4.98 mV/div DC–150 MHz DC–250 MHz 1 mV/div–1.99 mV/div DC–95 MHz DC–100 MHz

500 mV/div ≥40:1 at 50 MHz for any two channels having equal volts/division

≤9.95 mV/div ≥40:1 at 50 MHz for any two channels having equal volts/division

10 mV/div–500 mV/div ≥80:1 at 100 MHz and ≥30:1 at full bandwidth for any two

≤200 ps between CH 1 and CH 2 and between CH 3 and CH 4 when both channels have equal

volts/division and coupling settings ≤450 ps for any other combination of two channels with equal volts/division and coupling settings

1 M ±0.5% in parallel with 15 pF ±2.0 pF. Matched between channels to within ±1% for resistance and ±1.0 pF for capacitance

Bandwidth

settings

channels having equal volts/division settings

TDS 430A and TDS 460A Bandwidth

50  ±1% with VSWR ≤1.2:1 from DC–200 MHz

50  ±1% with VSWR ≤1.6:1 from DC–400 MHz

Volt/Div 

0.1 V/div–10 V/div

1 mV/div–99.9 mV/div 300 V CAT II; derate at 20 dB/decade above 10 kHz until the

5 V

, with peaks less than or equal to ±30 V

RMS

300 V CAT II; derate at 20 dB/decade above 10 MHz until the minimum rating of ±5 V (DC + peak AC) is reached

minimum rating of ±5 V (DC + peak AC) is reached

1–16

TDS 420A, TDS 430A & TDS 460A Service Manual

Warranted Characteristics

T able 1–10: Warranted Characteristics — Signal Acquisition System (Cont.)

Name Description

Lower Frequency Limit, AC

≤10 Hz when AC–1 M coupled; ≤200 kHz when AC-50  coupled

Coupled

Net Offset = Offset – (Position × Volts/Div). Net Offset is the voltage level at the center of the A-D converter dynamic range. Offset Accuracy is the accuracy of this voltage level.

The samples must be acquired under the same setup and ambient conditions.

DC Gain Accuracy is confirmed in the Performance Verification Procedure by passing the checks for Offset Accuracy and DC Voltage Measurement Accuracy (A veraged).

Position Accuracy is confirmed in the Performance Verification Procedure by passing the checks for Offset Accuracy and DC Voltage Measurement Accuracy (A veraged).

The limits given are for the ambient temperature range of 0_ C to +30_ C. Reduce the upper bandwidth frequencies by

2.5 MHz for each _C above +30_ C.

The AC Coupled Lower Frequency Limits are reduced by a factor of 10 when 10X, passive probes are used.

T able 1–11: Warranted Characteristics — Time Base System

Name Description Accuracy, Long Term Sample Rate and

Delay Time

Accuracy, Absolute Time and Delay Time Measurements

1,2

Accuracy, Delta Time Measurement

For input signals ≥ 5 divisions in amplitude and a slew rate of ≥ 2.0 divisions/ns at the delta time measurement

1, 2

points. Signal must have been acquired at a volts/division setting ≥ 5 mV/division and not in Events mode.

The WI (waveform interval) is the time between the samples in the waveform record. Also, see the footnotes for Sample Rate Range and Equivalent Time or Interpolated Waveform Rates in Table 1–4 on page 1–9.

±150 ppm over any ≥1 ms interval

For single-shot acquisitions using sample or high-resolution acquisition modes and a bandwidth limit setting of 100 MHz:

±(1 WI + 150 ppm of |Reading| + 450 ps)

For single-shot acquisitions using sample or high-resolution acquisition modes and a bandwidth limit setting of 20 MHz:

±(1 WI + 150 ppm of |Reading| + 1.3 ns)

For repetitive acquisitions using average acquisition mode with ≥8 averages and a bandwidth limit setting of FULL:

±(1 WI + 150 ppm of |Reading| + 200 ps)

For single-shot acquisitions using sample or high-resolution acquisition modes and a bandwidth limit setting of 100 MHz:

±(1 WI + 150 ppm of |Reading| + 650 ps)

For repetitive acquisitions using average acquisition mode with ≥8 averages and a bandwidth limit setting of FULL:

±(1 WI + 150 ppm of |Reading| + 300 ps)

TDS 420A, TDS 430A & TDS 460A Service Manual

1–17

Warranted Characteristics

Outpu

age and Frequency,

Probe

T able 1–12: Warranted Characteristics — Triggering System

Name Description Accuracy , Trigger Level or Threshold,

DC Coupled Sensitivity, Edge-Type Trigger, DC

Coupled

Sensitivity, Video-Type, TV Field and TV

Line

±(2% of |Setting – Net Offset1| + 0.2 div × volts/div setting + Offset Accuracy) for any channel as trigger source and for signals having rise and fall times ≥ 20 ns

0.35 division from DC to 50 MHz, increasing to 1 division at 350 MHz (TDS 420A) or 500 MHz (TDS 430A and TDS 460A) for any channel as trigger source

0.6 division of video sync signal

Pulse Width, minimum, Events-Delay 5 ns Auxiliary Trigger Input, External Clock Input Connector: BNC at rear panel

Input Load: equivalent to three TTL gate loads Input Voltage (maximum): –5 VDC to +10 VDC (TTL levels recommended)

Auxiliary Trigger, Maximum Input Frequency

10 MHz Duty Cycle High and low levels must be stable for ≥ 50 ns

Frequency, External Clock DC to 10 MHz High and low levels must be stable for ≥ 50 ns

Net Offset = Offset – (Position × Volts/Div). Net Offset is the voltage level at the center of the A-D converter dynamic range. Offset Accuracy is the accuracy of this voltage level.

The minimum sensitivity for obtaining a stable trigger. A stable trigger results in a uniform, regular display triggered on the selected slope. The trigger point must not switch between opposite slopes on the waveform, and the display must not “roll” across the screen on successive acquisitions. The TRIG’D LED stays constantly lighted when the SEC/DIV setting is 2 ms or faster but may flash when the SEC/DIV setting is 10 ms or slower.

T able 1–13: Warranted Characteristics — Probe Compensator Output

Name Description

t Volt

Compensato

Characteristic Limits

Voltage 0.5 V (base-top) ±5% into a 1 M load Frequency 1 kHz ±5%

T able 1–14: Warranted Characteristics — Power Requirements

Name Description

Source Voltage and Frequency

90 to 132 VAC 100 to 132 VAC 180 to 250 VAC

Power Consumption ≤240 Watts (370 VA)

1–18

CAT II, continuous range, for 48 Hz through 62 Hz

RMS

CAT II, continuous range, for 48 Hz through 440 Hz

RMS

CAT II, continuous range, for 48 Hz through 440 Hz

RMS

TDS 420A, TDS 430A & TDS 460A Service Manual

Warranted Characteristics

T able 1–15: W arranted Characteristics — Environmental, Safety, and Reliability

Name Description

Atmospherics T emperature1:

Operating, +0_ C to +50_ C (disk drive operation limited to +4_ C minimum); Nonoperating, –22_ C to +60_ C

Relative humidity:

Operating without disk, to 80%, at or below +29_ C; to 20%, at or below +50_ C; Operating with disk, 20% (+4_ C to +50_ C) to 80% (+4_ C to +29_ C) ; Nonoperating, 20% (+4_ C to +60_ C) to 90% (+22_ C to +40_ C)

Altitude:

Operating, to 15,000 ft. (4570 m); Nonoperating, to 40,000 ft. (12190 m)

Maximum operating temperature is decreased 1_ C per 1000 feet (305 meters) above 5000 feet (1525 meters).

TDS 420A, TDS 430A & TDS 460A Service Manual

1–19

Warranted Characteristics

T able 1–16: Certifications and compliances

EC Declaration of Conformity

1,2

Meets intent of Directive 89/336/EEC for Electromagnetic Compatibility and Low Voltage Directive 73/23/ECC for Product Safety. Compliance was demonstrated to the following specifications as listed in the Official Journal of the European Communities:

EN 50081-1 Emissions:

EN 55022 Class B Radiated and Conducted Emissions

EN 50082-1 Immunity:

IEC 801-2 Electrostatic Discharge Immunity IEC 801-3 RF Electromagnetic Field Immunity IEC 801-4 Electrical Fast Transient/Burst Immunity IEC 801-5 Power Line Surge Immunity

Low Voltage Directive 73/23/EEC: EN 61010-1 Safety requirements for electrical equipment for measurement,

control, and laboratory use FCC Compliance Emissions comply with FCC Code of Federal Regulations 47, Part 15, Subpart B, Class A Limits Certifications Underwriters Laboratories certified to Standard UL31 11-1 for Electrical Measuring and T est

Equipment. Canadian Standards Association certified to Standard CAN/CSA-C22.2 No. 1010.1-92, Safety

Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use. T emperature (operating) +0_ C to +50_ C Altitude (maximum operating) 2000 meters Safety Class Class I (as defined in IEC 1010–1, Annex H) – grounded product CSA Certified Power Cords CSA Certification includes the products and power cords appropriate for use in the North America

power network. All other power cords supplied are approved for the country of use. Overvoltage Category Category: Examples of Products in this Category:

CA T I Signal levels in special equipment or parts of equipment, telecommu-

nications, electronics CA T II CA T III

Pollution Degree 2

To maintain emission requirements when connecting to the IEEE 488 GPIB interface of this oscilloscope, use only a

Do not operate in environments where conductive pollutants may be present.

Local-level mains, appliances, portable equipment

Distribution-level mains, fixed installation

high-quality, double-shielded (braid and foil) GPIB cable. The cable shield must have low impedance connections to both connector housings. Acceptable cables are Tektronix part numbers 012-0991-00, -01, -02 and -03. To maintain EMI performance use the following cables, or their equivalent: a shielded Centronics cable, 3 meters long, part number 012-1214-00, and a shielded RS-232 cable, 2.7 meters long, CA part number 0294-9.

To maintain emission requirements when connecting to the VGA-compatible video output of this oscilloscope, use only a high-quality double-shielded (braid and foil) video cable with ferrite cores at both ends. The cable shield must have low impedance connections to both connector housings. An acceptable cable is LCOM part number CTL3VGAMM-5.

1–20

TDS 420A, TDS 430A & TDS 460A Service Manual

Typical Characteristics

Accurac

oltage Measurement

Not Average

Analo

t r Accessor Pro e Att c e

This section contains tables that list the various typical characteristics that describe the TDS 400A Digitizing Oscilloscopes.

Typical characteristics are described in terms of typical or average performance. Typical characteristics are not warranted.

This subsection lists only typical characteristics. A list of warranted characteristics starts on page 1–15.

T able 1–17: Typical Characteristics — Signal Acquisition System

Name Description

y, DC V

Frequency Limit, Upper, 100 MHz Bandwidth Limited

Frequency Limit, Upper , 20 MHz Bandwidth Limited

Nonlinearity

g Bandwidth, DC-1 M Coupled with

Standard-Accessory Probe Attached

Measurement Type DC Accuracy

Any Sample

Delta Volts between any two sam-

ples 100 MHz

20 MHz

1 DL, differential; ≤ 1 DL, integral, independently based

Volts/Div TDS 420A

5 mV/div–10 V/div DC–200 MHz DC–400 MHz 2 mV/div–4.98 mV/div DC–150 MHz DC–250 MHz 1 mV/div–1.99 mV/div DC–100 MHz DC–100 MHz

±(1.5% × (|reading – Net Offset1|) + Offset Accuracy + 0.13 div + 0.6 mV)

±(1.5% × |reading| + 0.26 div + 1.2 mV)

TDS 430A and TDS 460A

Bandwidth

TDS 420A, TDS 430A & TDS 460A Service Manual

1–21

Typical Characteristics

ettli

rror

T able 1–17: Typical Characteristics — Signal Acquisition System (Cont.)

Name Description

Step Response S

ng E

Volts/Div Setting Step Ampli-

Settling Error (%)

tude

20 ns 500 ns 20 ms

1 mV/div–99.5 mV/div ≤2 V ≤0.5 ≤0.2 ≤0.1 100 mV/div–995 mV/div ≤20 V ≤2.0 ≤0.5 ≤0.2 1 V/div–10 V/div ≤200 V ≤2.0 ≤0.5 ≤0.2

Net Offset = Offset – (Position x Volts/Div). Net Offset is the voltage level at the center of the A-D converter dynamic range. Offset Accuracy is the accuracy of this voltage level.

The samples must be acquired under the same setup and ambient conditions.

A DL (digitization level) is the smallest voltage level change that can be resolved by the 8-bit A-D Converter with the input scaled to the volts/division setting of the channel used. Expressed as a voltage, a DL is equal to 1/25 of a division times the volts/division setting.

The values given are the maximum absolute difference between the value at the end of a specified time interval after the mid-level crossing of the step and the value one second after the mid-level crossing of the step, expressed as a percentage of the step amplitude.

T able 1–18: Typical Characteristics — Time Base System

Name Description

Aperture Uncertainty For real-time or interpolated records having duration ≤1 minute:

≤(50 ps + 0.03 ppm × Record Duration) RMS

For equivalent time records:

≤(50 ps + 0.06 ppm × WI1) RMS Fixed Error in Sample Time ≤50 ps External Clock sampling uncertainty ±8 ns External Clock Edge to Sampling Time

Delay

External Clock Minimum Prerecord points 55 points before the first visible sample in the record at the maximum clock speed

External Clock Minimum Postrecord points 25 points after the last visible sample in the record

You set the maximum external clock rate using the Horizontal Clock menu.

Sample –20 ns (Sample edge is delayed relative the the sample moment.) Hi Res Hi Res averaging starts within 8 ns of the clock edge.

Averaging stops after 1/(maximum external clock rate

)

Peak Detect Runs continuously at 100 MS/s

35 points before the first visible sample in the record at slow clock speeds

1–22

TDS 420A, TDS 430A & TDS 460A Service Manual

Typical Characteristics

rror

Positio

eri

ternal

Cloc

sitivit

Not DC Couple

T able 1–19: Typical Characteristics — Triggering System

Name Description

, Trigger

n, Edge Trigg

ng Acquire Mode Trigger-Position Error

Sample, Hi-Res, Average ±(1 WI + 1 ns) Peak Detect, Envelope ±(2 WI + 1 ns)

Holdoff, Variable, Main Trigger, In

k and non TV Trigg

Main Horizontal Scale Minimum Holdoff Maximum Holdoff

≤100 ns/div 1 ms 5 × Min Holdoff ≥100 ms/div 1 s 5 ×Min Holdoff

Otherwise 10 × sec/div 5 × Min Holdoff Holdoff, V ariable, External Clock 0 to 100 ms Auto Trigger Operation, External Clock Auto triggers 2 s after the last normal trigger or appropriated trigger mode is entered Lowest Frequency for Successful Opera-

20 Hz tion of “Set Level to 50%” Function

Sen

y, Edge Trigger,

d3Trigger Coupling Typical Signal Level for Stable Triggering

AC Same as DC-coupled limits4 for frequencies above

60 Hz. Attenuates signals below 60 Hz Noise Reject Three and one-half times the DC-coupled limits High Frequency Reject One and one-half times the DC-coupled limits4 from

DC to 30 kHz. Attenuates signals above 30 kHz Low Frequency Reject One and one-half times the DC-coupled limits4 for

frequencies above 80 kHz. Attenuates signals below

80 kHz

Video Mode (Option 05 Equipped Instruments Only)

Line Rate Class: Four classes are provided as follows  NTSC, which provides a default line rate compatible with the NTSC standard

(525/60)

1,2

 PAL, which provides a default line rate compatible with the PAL standard (625/50)  SECAM, which provides a default line rate compatible with the SECAM standard

(625/50)

 Custom, which provides user selectable line rate ranges (see Custom Line Rate

Ranges below)

Custom Line Rate Ranges: 15 kHz–20 kHz, 20 kHz–25 kHz, 25 kHz–35 kHz, and 35 kHz–64 kHz

Holdoff: Automatically adjusts to 58 ms (nominal) for NTSC class; to 150 ms (nominal) for PAL and SECAM. A holdoff of 0 to 100 typically covers a range of 1 to 400 ms

Triggerable on Field Selections: Odd, Even, or Both Delayed Acquisition: Settable for delay by line number or runs after time delay

Frequency, Maximum for Events Delay

90 MHz

TDS 420A, TDS 430A & TDS 460A Service Manual

1–23

Typical Characteristics

T able 1–19: Typical Characteristics — Triggering System (Cont.)

Name Description

Width, Minimum Pulse and Rearm, Events

Delay

The trigger position errors are typically less than the values given here. These values are for triggering signals having a

5 ns

slew rate at the trigger point of ±0.5 division/ns.

The waveform interval (WI) is the time between the samples in the waveform record. Also, see the footnote for the characteristics Sample Rate Range and Equivalent Time or Interpolated Waveform Rates in Table 1–4 on page 1–9.

See the characteristic Sensitivity, Edge-T ype T rigger, DC Coupled in Table 1–12, which begins on page 1–18.

The maximum frequency for a delaying events input.

The minimum pulse width and rearm width required for recognizing a delaying event.

T able 1–20: Typical Characteristics — Data Handling

Name Description

Time, Data-Retention, Nonvolatile

1,2

Memory

Nonvolatile Memory Save Time 10 seconds Floppy Disk Drive Capacity 3.5 in. floppy disk, 720 KB or 1.44 MB, compatible with DOS 3.3 format for storing

The time that reference waveforms, stored setups, and calibration constants are retained when there is no power to the oscilloscope.

Data is maintained by lithium poly-carbon monofluoride.

Internal batteries, installed at time of manufacture, have a life of ≥5 years when operated and/or stored at an ambient temperature from 0_ C to 50_ C. Retention time of the nonvolatile memories is equal to the remaining life of the batteries

waveforms, hard copies, and instrument setups

1–24

TDS 420A, TDS 430A & TDS 460A Service Manual

Installation

This chapter contains information about supplying operating power, the operating environment, applying and interrupting power, repackaging for shipment, and installed options.

Supplying Operating Power

STOP. Read all information and heed all warnings in this chapter before connecting the digitizing oscilloscope to a power source.

WARNING. AC POWER SOURCE AND CONNECTION. The digitizing oscilloscope operates from a single-phase power source. It has a three-wire power cord and a two-pole three-terminal grounding type plug. The voltage to ground (earth) from either pole of the power source must not exceed the 250 V maximum rated operating voltage.

RMS

Power Cord Information

Before making connection to the power source, be sure the digitizing oscilloscope has a suitable two-pole three-terminal grounding-type plug.

GROUNDING. This instrument is safety Class 1 equipment (IEC designation). All accessible conductive parts are directly connected through the grounding conductor of the power cord to the grounded (earthing) contact of the power plug.

The power input plug must be inserted only in a mating receptacle with a grounding contact where earth ground has been verified by a qualified service person. Do not defeat the grounding connection. Any interruption of the grounding connection can create an electric shock hazard.

For electric shock protection, the grounding connection must be made before making connection to the oscilloscope input or output terminals.

A power cord with appropriate plug configuration is supplied with each digitizing oscilloscope. Table 2–1 gives the color coding of the conductors in the power cord. If you require a power cord other than the one supplied, refer to Table 2–2.

TDS 420A, TDS 430A & TDS 460A Service Manual

2–1

Installation

T able 2–1: Power-Cord Conductor Identification

Conductor Color Alternate Color

Ungrounded (Line) Brown Black Grounded (Neutral) Light Blue White Grounded (Earthing) Green/Y ellow Green

T able 2–2: Power Cord Identification

Plug Configuration Normal Usage Option Number

North America 125 V

Europe 230 V

United Kingdom 230 V

Australia 230 V

North America 230 V

Switzerland 230 V

Standard

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Operating Voltage

The line voltage ranges and their associated line frequency ranges over which this oscilloscope operates are listed in Chapter 1 Specification. See Source Voltage and Frequency on page 1–18 for those ranges.

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CAUTION. Before stepping the source line voltage from one range to a higher range, set the principal power switch (rear panel) to its OFF position. Failure to do so can damage the oscilloscope.

There are two fuses. Either fuse may be used throughout the line voltage and frequency ranges. These two fuses are not totally interchangeable as each requires a different fuse cap. The fuses and their caps are listed by part number in Chapter 10, Mechanical Parts List.

Memory Backup Power

Operating Environment

Operating Temperature

Ventilation Requirements

Replaceable lithium batteries maintain internal memory modules to allow the digitizing oscilloscope to retain the following data upon loss of the AC power source: stored adjustment constants, saved front-panel settings, current front-panel settings (oscilloscope status), and saved waveforms.

These batteries have a shelf life of about five years. Partial or total loss of stored settings upon powering on may indicate that you need to replace the batteries.

The following environmental requirements are provided to ensure proper operation and long oscilloscope life.

Operate the oscilloscope where the ambient air temperature is between 0_ C and +50_ C, and store the oscilloscope at an ambient temperature from –40_ C to +75_ C. After storage at temperatures outside the operating limits, allow the chassis to stabilize at a safe operating temperature before applying power.

The digitizing oscilloscope is cooled by air drawn in and exhausted through its cabinet side panels by an internal fan. To ensure proper cooling of the oscilloscope, allow at least 50.8 mm (2 inches) clearance on both sides and 19 mm

(

inch) on the bottom of the digitizing oscilloscope. (The feet on the bottom of

the oscilloscope provide the required clearance when set on flat surfaces.) The top of the oscilloscope does not require ventilation clearance.

CAUTION. If air flow is restricted, the power supply of the digitizing oscilloscope may temporarily shut down.

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Applying and Interrupting Power

Consider the following information when you power up or power down the oscilloscope or when power is interrupted due to an external power failure.

Power-On

Power-Off

Upon powering on, the oscilloscope runs its power-on self check. If the self check passes, the oscilloscope displays a “passed” status message and a prompt to press CLEAR MENU to continue. If the self check fails, the oscilloscope displays a diagnostic log that identifies the area(s) that failed and a prompt to press CLEAR MENU to continue. See Chapter 6, Maintenance, for information on diagnostics and fault isolation.

CAUTION. DO NOT power down the oscilloscope when either running a signal path compensation or when doing any of the adjustments described in Chapter 5, Adjustment Procedures. To do so might result in the loss of internally stored adjustment constants.

In general, do not power off the oscilloscope when doing operations that affect the data types listed in Table 2–3. Wait for the oscilloscope to finish the operation when doing adjustments, saving waveforms, or saving setups. After operations complete, wait at least four more seconds before turning the power off.

Improper power-down or unexpected loss of power to the oscilloscope can result in corruption of non-volatile RAM (NVRAM). The following table describes the messages displayed when power is restored after an abnormal power-down.

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T able 2–3: Effects of Corrupted Data

Corrupted Data Type Results

Adjustment Constants:

 Signal Path Compensation  Voltage Reference

 Low or High Frequency Response

 Trigger Skew

Error Log Errors logged are lost

A signal path compensation is required. A voltage reference adjustment is required

(Chapter 5) A frequency response adjustment is required

(Chapter 5) A trigger skew adjustment is required

(Chapter 5)

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T able 2–3: Effects of Corrupted Data (Cont.)

Corrupted Data Type Results

Reference Waveforms Waveform Lost Saved Setups Setup Lost

Repackaging Instructions

Use a corrugated cardboard shipping carton having a test strength of at least 125 kg (275 pounds) and with an inside dimension at least 152.4 mm (6 inches) greater than the oscilloscope dimensions. (The original shipping carton, if available, meets these requirements.)

If the oscilloscope is being shipped to a Tektronix Service Center, enclose the following information: the owner’s address, the name and phone number of a contact person, the type and serial number of the oscilloscope, the reason for returning to oscilloscope, and a complete description of the service required.

Installation

Installed Options

Seal the shipping carton with an industrial stapler or strapping tape. Mark the address of the Tektronix Service Center and also your own return

address on the shipping carton in two prominent locations.

Your oscilloscope may be equipped with one or more options. Except for the line-cord options described by Table 2–2 (on page 2–2 of this chapter), all options and optional accessories are listed and described in Chapter 7, Options. For further information and prices of oscilloscope options, see your Tektronix Products catalog or contact your Tektronix Field Office.

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Operating Information

Before doing service, read the following operating instructions. These instructions are at the level appropriate for servicing this digitizing oscilloscope. The complete operators instructions are found in the user manual.

Additional instructions are integrated into the service procedures found in later chapters of this manual. For instance, the procedures found in the Performance Verification chapter, starting on page 4–1, contain instructions for making the front-panel settings required to check each oscilloscope characteristic included there. Also, the general instructions for operating the internal diagnostic routines are found in the, Maintenance chapter, starting on page 6–1. You may also find the Product Description, starting on page 1–1, useful for understanding how the oscilloscope functions.

Screen Layout

The screen layout is illustrated in Figure 2–1 on page 2–8. Note that the figure illustrates a full graticule; you may also select a grid, crosshair, or frame graticule from the display menu.

Basic Procedures

How to Power On

Push the principal power switch found on the rear panel of the digitizing oscilloscope, then push the ON/STBY (standby) switch to toggle the digitizing oscilloscope into operation. The switch at the rear panel is the true power disconnect switch. The ON/STBY(standby) switch simply toggles operation on and off.

WARNING. The principal power switch at the rear panel is the true power disconnect switch. The ON/STBY (standby) switch simply toggles operation on and off. When connected to a power source and when the principal power switch is on, some power supply circuitry in this digitizing oscilloscope is energized regardless of the setting of the ON/STBY switch.

When connecting or disconnecting the line cord to or from the power source, the principal power switch should be off.

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Operating Information

Position of Waveform

Record Relative to

the Screen and Display

Waveform Reference

Symbols: Ground Levels

and Waveform Sources

Graticule and Waveforms

Vertical Scale, Horizontal

Scale, and Trigger Level

Readouts

Brief Status

Information

General Purpose

Knob Readout

Side menu area. Readouts for measurements move here when CLEAR MENU is pressed.

Using Help

Using the Status Menu

Main menu display area. Readouts in lower graticule

area move here when CLEAR MENU is pressed.

Figure 2–1: Map of Display Functions

Push the HELP front-panel button to enter help mode. Front-panel knobs and buttons now display information about their function when turned or pushed. Push HELP again to exit help mode.

To get help information on a menu item, display the menu desired (if you are in help mode, exit help first). Push HELP. Now the menu buttons display information about their function when pushed.

Push the SHIFT button, and then press the STATUS front-panel button. Then press the STATUS main-menu button to display the status menu. The messages reflect the state of the acquisition system, whether it is running or stopped (and if it is stopped, why), as well as setup-related information.

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Operating Information

Setting Functions

Special Controls Block: Accesses

all functions except those in the

remaining three control blocks.

You set most functions by either using one or two front-panel buttons or knobs, or by pushing a front-panel button to use a main menu, and then a side menu to set the function. The following steps illustrate both procedures.

1. Locate the block that contains the function to be set.

Vertical Controls and

Inputs Block

Horizontal Controls

Block

Trigger Controls

Block

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Operating Information

2. Select the waveform source(s). Position, scale, and set trigger level for

waveform source(s) directly from the front-panel. (Note that parentheses-enclosed numbers appear within the following steps. Each number refers to the control(s) labeled with the same number in the figure that precedes the step.)

a. Input waveforms into these channels (7). Example: CH 1. b. Push any channel button (8) to display its waveform. The last channel

selected determines which waveform is positioned and scaled. The indicator above the channel last selected is lighted. Example: Push

CH 1; then CH 2.

c. Vertically (1) and horizontally (2) scale and position the waveform(s)

selected. Example: Set the scale to 100 mV/div, and center the waveform on screen.

d. Stop and start acquiring waveforms (3). Example: Push RUN/STOP if

not acquiring.

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Operating Information

e. Adjust trigger level (5) to trigger the waveform(s) selected, or use these

buttons (6) to either set a trigger level at the mid-amplitude level of the selected waveform or to force a single trigger. Example: Push SET

LEVEL TO 50%.

3. Set all other functions using menus. a. Choose the waveform source (8) first if setting a vertical function; else

skip to step b. Example: Push CH 2.

b. Push SHIFT (4) if the function to be set is highlighted in blue; else skip

to step c.

c. Push the front-panel button that corresponds to the menu containing the

function. A main menu (14) for selecting among related functions appears. Example: Push VERTICAL MENU.

Note the two labels: the top label is a function to choose from; the bottom label tells you the current setting for that function. Offset is currently set to –1.4 V.

d. Select a function from the main menu using the main menu buttons (12).

A side menu for selecting among the available settings for that function appears. Example: Push Coupling (13).

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Operating Information

e. Select the setting for the function from the side menu (9) using the side

menu buttons (11). Example: Push AC (10).

How to Set Complex

Functions

A few functions require more than just two levels (main and side) of menus to completely specify their settings. In such cases, either the main menu, the side menu, or both are modified to supply additional choices. The procedures that follow show both schemes.

1. Set up a function using pop-up menus:

2–12

a. For some selections, pushing a main menu button pops up a menu (18)

of subfunctions. Example: Push SHIFT; then push UTILITY. Now push System (17).

Note the pop-up menu for System is set to I/O (input/output). All the main menu buttons to the right of the pop-up menu are labeled with subfunctions of I/O.

b. Pushing the button that popped up the menu (17) toggles through the

pop-up menu choices. Example: Repeatedly push System to toggle through the pop-up menu. Notice the other main-menu button labels change accordingly. Toggle back to I/O.

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Operating Information

c. Complete the setting of the desired mode by selecting from the main

menu and the side menu that results. Example: Push Configure (16), and then push Hardcopy (Talk only) (15).

2. Set up a function using the general purpose knob (20). (The examples of possible menu selections in the substeps that follow assume you have pushed TRIGGER MENU.)

2019

a. Pushing some main menu buttons displays a side menu with labels

containing readouts that you can vary. Example: Push Level (21).

b. Pushing the side-menu button assigns the knob to control the readout

appearing in the button label. It also copies the readout to the general purpose knob readout area in the right corner of the screen. Example: Push Level (19).

c. Use the general purpose knob (20) to adjust the trigger level to the

setting desired. Example: Turn the knob to –20 mV.

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Operating Information

More About the General Purpose Knob. As you have just seen, the general purpose knob is used to extend the number of choices available to a side menu button. You can also assign the general purpose knob to control additional functions. Some of these additional functions include:

 Cursor positioning  Display intensities  Delay time  Number of events  Trigger position  Holdoff  Offset  Variable persistence  File system

In all cases, the menus are used to select the function to which the general purpose knob is assigned. The following attributes apply to this knob:

 Depending on the function it is assigned to control, the general purpose knob

varies numerical readouts, positions objects (cursors) on screen, or selects between icon-label settings that show up in side-menu labels.

 The general purpose knob has a readout area at the upper-right corner of the

screen. (See Figure 2–1.) This readout always reflects the name and value of the function that the general purpose knob is currently controlling.

 The general purpose knob is affected by the SHIFT button. Pressing shift

toggles the knob between its fine and coarse modes. Fine mode is used for most adjustments; coarse mode is used to traverse large parts of the adjustment range in less time.

 Whenever the general purpose knob assignment is changed, a knob icon

appears immediately to the left of the general purpose knob readout to notify you of the assignment change. The icon is removed as soon as you use the general purpose knob to change the value of the function it is assigned to.

 To assign the general purpose knob to control a function, display the menu

containing the function; then select the function. (Note that the general purpose knob cannot control all functions.)

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Operating Information

 Whenever the menu is removed, the general purpose knob is not assigned

and does not control a function. (An exception is the cursor function. If cursors are turned on, removing the menu leaves the knob assigned to control the cursors until reassigned by selecting another menu and function that uses the knob.)

 The general purpose knob also has a SELECT button. Use the select button

to toggle the knob between the control of either of the two cursors displayed when H-bar or V-bar cursors are turned on in the cursor menu, to select the active graticule in zoom preview, to traverse the file system, and to enter characters when naming files.

Display and Utility Menus. Using the techniques described for using menus, you can access and change functions in the display menu and utilities menu. In the Display menu, you can set the following functions:

 Intensity: waveforms, readouts, and graticule  Style of waveform display(s): vectors or dots, intensified or non-intensified

samples, and infinite or variable persistence

 Display format: XY or YT  Graticule format: full, grid, crosshair, frame, NTSC, and PAL  Waveform interpolation filter and readout options

From the Utility menu, you can configure the GPIB port (talk/listen, address, etc.) and access internal routines for self diagnostics and self compensation. Instructions for setting up communication over the GPIB are found in the Adjustment Procedures, starting on page 5–1.

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Operating Information

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Theory of Operation

This chapter describes the electrical operation of the Tektronix TDS 420A, TDS 430A, and TDS 460A Digitizing Oscilloscopes using the major circuit blocks or modules.

This chapter has two main parts:  Logic Conventions describes how logic functions are discused and

represented in this manual.

 Module Overview describes circuit operation from a functional

block perspective.

Logic Conventions

The digitizing oscilloscope contains many digital logic circuits. This manual refers to these circuits with standard logic symbols and terms. Unless otherwise stated, all logic functions are described using the positive-logic convention: the more positive of the two logic levels is the high (1) state, and the more negative level is the low (0) state. Signal states may also be described as “true” meaning their active state or “false” meaning their non-active state. The specific voltages that constitute a high or low state vary among the electronic devices.

Module Overview

General

Input Signal Path

Active-low signals are indicated by a tilde prefixed to the signal name (~RESET). Signal names are either active-high, active-low, or have both active-high and active-low states.

This module overview describes the basic operation of each functional circuit block as shown in Figure 9-2 on page 9–4.

The digitizing oscilloscope is a portable, multichannel instrument. Each channel provides a calibrated vertical scale factor. All channels can be acquired simultaneously.

A signal enters the oscilloscope through a probe connected to a BNC on the A05 Attenuator board.

Attenuators. Circuitry in the attenuator selects the input coupling, the termination, and the attenuation factor. The processor system controls the attenuators.

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Theory of Operation

For example, if 50 W input termination is selected and the input is overloaded, the processor system switches the input to the 1 MW position. The preamplifier in the A05 Attenuator amplifies the input signals.

Probe Coding Interface. Probe coding interface signals pass through the A06 Front Panel to the processor system.

Jumper. Signals from the attenuators pass through the A08 Jumper board to the acquisition system.

Acquisition System. The acquisition system converts the analog input signals to digital signals and controls the acquisition process under direction of the processor system. The acquisition system includes the trigger, acquisition timing, and acquisition mode generation and control circuitry.

D1 Bus. The acquisition system passes the digital values representing the acquired waveform through the D1 bus to the A09 DSP board (TriStar). This happens after a waveform acquisition is complete if the digital signal processor (DSP) requests the waveform.

Processor System. The processor system consists of a 68020 microprocessor that controls the entire instrument. It includes the firmware program for the oscilloscope. The firmware can be reprogrammed by using the GPIB and an external software package. The processor system also includes a GPIB interface. The processor can display text and symbols (that is, cursors, but not waveforms) by passing them to the A02 Display board.

DSP. The digital signal processor processes each waveform as directed by software downloaded from the system processor. Waveforms to be displayed are passed on to the A02 Display board.

Display. Text and waveforms are processed by different parts of the A02 Display circuitry. The display sends the text and waveform information to the A26 Monitor assembly as a video signal. The display circuitry also generates and sends vertical (VSYNC) and horizontal (HSYNC) sync signals to the A26 Monitor assembly. A VGA-compatible video output is available at the rear of the oscilloscope.

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Theory of Operation

Monitor Assembly

Front Panel

Rear Panel

All information (waveforms, text, graticules, and pictographs) is displayed by the A20 CRT Driver. The driver generates the high voltages necessary to drive the CRT. It also contains the video amplifier, horizontal oscillator, and the vertical and horizontal yoke driver circuitry. The monitor gets its supply voltages from the A25 Low Voltage Power Supply through the A01 Backplane and the A07 Auxiliary Power boards.

The processor system sends instructions to and receives information from the Front Panel Processor on the A06 Front Panel board. The Front Panel Processor reads the front-panel switches and pots. Any changes in their settings are reported to the processor system. The Front Panel Processor also turns the LEDs on and off, generates the bell signal, and generates the probe compensation signal PROBE ADJ. The Front Panel Processor also processes the probe coding interface signals.

The ON/STBY switch is not read by the Front Panel Processor. The signal passes through the A06 Front Panel board to the A03 CPU board. There it’s converted to a control signal for the low voltage power supply.

The GPIB connector provides access to stored waveforms and allows external control of the oscilloscope. Other connectors accessible from the rear panel are the AUX TRIGGER/EXT CLOCK and VIDEO.

Aux Power

Low Voltage Power Supply

Fan

Battery

The A07 Auxiliary Power circuitry includes the principal power switch, fuse, line trigger transformer, and line filter. It also distributes power to the monitor and fan.

The low voltage power supply is a switching power converter. It supplies power to all oscilloscope circuitry. The low voltage power supply sends all of its power to the A01 Backplane where it is distributed to all other circuitry.

The principal POWER switch, located on the rear panel, controls all power to the oscilloscope including the low voltage power supply. The ON/STBY switch, located on the front panel, also controls all of the power to the oscilloscope except for part of the circuitry in the low voltage power supply.

The fan provides forced air cooling for the oscilloscope. It connects to +12 V on the A01 Backplane through the A07 Auxiliary Power board.

The battery provides power to memory circuits that maintain calibration constants and oscilloscope setups when the oscilloscope power is off.

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Theory of Operation

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Performance Verification Procedures

Two types of Performance Verification procedures can be performed on this product: Brief Procedures and Performance Tests. You may not need to perform all of these procedures, depending on what you want to accomplish:

 To rapidly confirm that this oscilloscope functions and is adjusted properly,

just do the procedures under Self Tests, which begin on page 4–5. Advantages: These procedures are quick to do, require no external

equipment or signal sources, and perform extensive functional and accuracy testing to provide high confidence that the oscilloscope will perform properly. Use these procedures as a quick check before making a series of important measurements.

 To further check functionality, first do the Self Tests just mentioned; then do

the procedures under Functional Tests that begin on page 4–7. Advantages: These procedures require minimal additional time to perform,

require no additional equipment other than a standard-accessory probe, and more completely test the internal hardware of this oscilloscope. Use these procedures to quickly determine if the oscilloscope is suitable for putting into service, such as when it is first received.

 If more extensive confirmation of performance is desired, do the Perfor-

mance Tests, beginning on page 4–15, after doing the Functional and Self Tests just referenced.

Advantages: These procedures add direct checking of warranted specifications. They require more time to perform and suitable test equipment is required. (See Equipment Required on page 4–16.)

If you are not familiar with operating this oscilloscope, read Operating Informa- tion in Chapter 2 of this manual. These instructions will acquaint you with the use of the front-panel controls and the menu system.

Throughout these procedures the following conventions apply:  Each test procedure uses the following general format:

Title of Test Equipment Required Prerequisites Procedure

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Performance Verification Procedures

 Each procedure consists of as many steps and substeps as required to do the

 In steps and substeps, the lead-in statement in italics instructs you what to

 Where instructed to use a front-panel button or knob, or select from a main

test. Steps and substeps are sequenced as follows:

1. First Step a. First Substep b. Second Substep

2. Second Step

do, while the instructions that follow tell you how to do it: in the example step below, “Initialize the oscilloscope” by doing “Press save/recall SETUP. Now, press the main-menu button...”

Initialize the oscilloscope: Press save/recall SETUP. Now, press the main-menu button Recall Factory Setup; then the side-menu button OK Confirm Factory Init.

or side menu, or verify a readout or status message, the name of the button or knob appears in boldface type: “press SHIFT; then ACQUIRE MENU,” “press the main-menu button Coupling,” or “verify that the status message is Pass.”

STOP. This symbol is accompanied by information you must read to do procedures properly.

 Refer to Figure 4–1: “Main menu” refers to the menu that labels the seven

menu buttons under the display; “side menu” refers to the menu that labels the five buttons to the right of the display.

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Performance Verification Procedures

Position of Waveform

Record Relative to

the Screen and Display

Waveform Reference

Symbols: Ground Levels

and Waveform Sources

Graticule and Waveforms

Vertical Scale, Horizontal

Scale, and Trigger Level

Readouts

Brief Status Information

General Purpose

Knob Readout

Side menu area. Readouts for measurements move here when CLEAR MENU is pressed.

Figure 4–1: Map of Display Functions

Main menu display area. Readouts in lower graticule

area move here when CLEAR MENU is pressed.

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Performance Verification Procedures

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Brief Procedures

Self Tests

The Self Tests use internal routines to confirm basic functionality and proper adjustment. No test equipment is required to do these test procedures.

The Functional Tests use the probe-adjust output at the front panel as a test- signal source for further verifying that the oscilloscope functions properly. A standard-accessory probe, included with this oscilloscope, is the only equipment required.

This procedure uses internal routines to verify that this oscilloscope functions and passes its internal self tests and signal path compensations. It also confirms that the oscilloscope was adjusted properly at the time it was last adjusted. No test equipment or hookups are required.

Verify Internal Adjustment,

Self Compensation, and

Diagnostics

Equipment Required

Prerequisites Power on the digitizing oscilloscope and allow a 20 minute warm-up

1. Verify that internal diagnostics pass: Do the following substeps to verify that

the internal diagnostics passed.

a. Display the system diagnostics menu:

 Press SHIFT; then press UTILITY.  Repeatedly press the main-menu button System until Diag/Err is

highlighted in the menu that pops up.

 Repeatedly press the main-menu button Area until All is highlighted

in the menu that pops up.

b. Run the system diagnostics: Press the main-menu button Execute; then

press the side-menu button OK Confirm Run Test.

c. Wait: The internal diagnostics do an exhaustive verification of proper

oscilloscope function. This verification takes up to two minutes. While it progresses, a variety of test patterns flash on screen. When finished, the resulting status appears on the screen.

None

before doing this procedure.

d. Confirm no failures are found: Verify that no failures are found and

reported on screen.

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Brief Procedures

e. Confirm the four adjustment sections have passed status:

 Press SHIFT; then press UTILITY.  Press the main menu button System until Cal is highlighted in the

pop-up menu.

 Verify that the word Pass appears in the main menu under the

following menu labels: Voltage Reference, High Frequency Response, Low Frequency Response, and Trigger Skew. (See Figure 4–2.)

Display the

CAL menu.

Run a signal path

compensation and verify

status is Pass.

Verify Pass status for the

adjustment sections.

Figure 4–2: Verifying Adjustments and Signal Path Compensation

This oscilloscope lets you compensate the internal signal path used to acquire the waveforms you acquire and measure. By executing the signal path compensation feature (SPC), you optimize the oscilloscope capability to make accurate measurements based on the ambient temperature.

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Brief Procedures

You must run an SPC anytime you wish to ensure that the measurements you make are made with the most accuracy possible. You should also run an SPC if the temperature has changed more than 5_ C since the last SPC was performed.

f. Run the signal path compensation: Disconnect all input signals. Press

the main-menu button Signal Path; then press the side-menu button OK Compensate Signal Paths.

NOTE. Failure to run the signal path compensation may result in the oscilloscope not meeting warranted performance levels.

g. Wait: signal path compensation runs in one to three minutes. While it

progresses, a “clock” icon (shown at left) displays on screen. When compensation completes, the status message updates to Pass or Fail in the main menu (see step h).

h. Confirm signal path compensation returns passed status: Verify the

word Pass appears under Signal Path in the main menu. (See Figure 4–2.)

Functional Tests

2. Return to regular service: Press CLEAR MENU to exit the system menus.

The purpose of these procedures is to confirm that this oscilloscope functions properly. The only equipment required is one of the standard-accessory probes and a 3.5

I, 720 K or 1.44 Mbyte floppy disk.

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Brief Procedures

STOP. These procedures verify functions; that is, they verify that oscilloscope features operate. They do not verify that they operate within limits. Therefore, when the instructions in the functional tests that follow call for you to verify that a signal appears on screen “that is about five divisions in amplitude” or “has a period of about six horizontal divisions,” and so forth, do NOT interpret the quantities given as limits. Operation within limits is checked in Performance Tests, which begin on page 4–15.

DO NOT make changes to the front-panel settings that are not called out in the procedures. Each verification procedure requires you to set the oscilloscope to certain default settings before verifying functions. If you make changes to these settings, other than those called out in the procedure, you may obtain invalid results. In this case, just redo the procedure from step 1.

When you are instructed to press a menu button, the button may already be selected (its label will be highlighted). If this is the case, it is not necessary to press the button.

Verify All Input Channels

Equipment Required

Prerequisites None

One P6138A probe

1. Install the test hookup and preset the oscilloscope controls:

Digitizing Oscilloscope

Figure 4–3: Universal Test Hookup for Functional Tests

4–8

a. Hook up the signal source: Install the probe on CH 1. Connect the probe

tip to PROBE ADJ on the front panel; leave the probe ground unconnected.

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Brief Procedures

b. Initialize the oscilloscope:

 Press save/recall SETUP.  Press the main-menu button Recall Factory Setup.  Press the side-menu button OK Confirm Factory Init.

2. Verify that all input channels operate: Do the following substeps — test

CH 1 first, skipping substep a since CH 1 is already set up for verification

from step 1. a. Select an unverified channel:

 Press WAVEFORM OFF to remove from display the channel

just verified.

 Press the front-panel button that corresponds to the channel you are

to verify.

 Move the probe to the channel you selected.

b. Set up the selected channel:

 Press AUTOSET to obtain a viewable, triggered display in the

selected channel.

 Set the vertical SCALE to 100 mV. Use the vertical POSITION

knob to center the waveform vertically on screen.

 Set the horizontal SCALE to 200 ms.  Press TRIGGER MENU.  Press the main-menu button Coupling; then press the side menu-

button HF Rej.

c. Verify that the channel is operational: Confirm that the following

statements are true.  The vertical scale readout for the channel under test shows a setting

of 100 mV, and a square-wave probe-compensation signal about five divisions in amplitude is on screen. (See Figure 4–1 on page 4–3 to locate the readout.)

 The vertical POSITION knob moves the signal up and down the

screen when rotated.

 Turning the vertical SCALE knob counterclockwise decreases the

amplitude of the waveform on-screen, turning the knob clockwise increases the amplitude, and returning the knob to 100 mV returns the amplitude to about five divisions.

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Brief Procedures

d. Verify that the channel acquires in all acquisition modes: Press SHIFT;

then press ACQUIRE MENU. Use the side menu to select, in turn, each of the five hardware acquire modes and confirm that the following statements are true. Refer to the icons at the left of each statement as you confirm those statements.

 Sample mode displays an actively acquiring waveform on screen.

(Note that there is noise present on the peaks of the square wave.)

 Peak Detect mode displays an actively acquiring waveform on

screen with the noise present in Sample mode “peak detected.”

 Hi Res mode displays an actively acquiring waveform on screen

with the noise that was present in Sample mode reduced.

 Envelope mode displays an actively acquiring waveform on screen

with the noise displayed.

 Average mode displays an actively acquiring waveform on screen

with the noise reduced like in Hi Res mode.

Verify the Time Base

e. Test all channels: Repeat substeps a through d until all input channels

are verified.

3. Remove the test hookup: Disconnect the probe from the channel input and

the probe-adjust terminal.

Equipment Required

Prerequisites None

One P6138A probe

1. Install the test hookup and preset the oscilloscope controls: a. Hook up the signal source: Install the probe on CH 1. Connect the probe

tip to PROBE ADJ on the front panel; leave the probe ground unconnected. (See Figure 4–3 on page 4–8.)

b. Initialize the oscilloscope:

 Press save/recall SETUP.  Press the main-menu button Recall Factory Setup; then press the

side-menu button OK Confirm Factory Init.

4–10

c. Modify default settings:

 Press AUTOSET to obtain a viewable, triggered display.  Set the horizontal SCALE to 200 ms.

TDS 420A, TDS 430A & TDS 460A Service Manual

Brief Procedures

 Press VERTICAL MENU.  Press the main-menu button Bandwidth. Then press the side-menu

button 20 MHz.

 Press CLEAR MENU to remove the vertical menu from the screen.

2. Verify that the time base operates: Confirm the following statements. a. One period of the square-wave probe-compensation signal is about five

horizontal divisions on-screen for the 200 ms horizontal scale setting (set in step 1c).

b. Rotating the horizontal SCALE knob clockwise expands the waveform

on-screen (more horizontal divisions per waveform period), counterclockwise rotation contracts it, and returning the horizontal scale to 200 ms returns the period to about five divisions.

c. The horizontal POSITION knob positions the signal left and right on

screen when rotated.

Verify the Main and

Delayed Trigger Systems

3. Remove the test hookup: Disconnect the probe from the channel input and the probe-adjust terminal.

Equipment Required

Prerequisites None

One P6138A probe

1. Install the test hookup and preset the oscilloscope controls: a. Hook up the signal source: Install the probe on CH 1. Connect the probe

tip to PROBE ADJ on the front panel; leave the probe ground unconnected. (See Figure 4–3 on page 4–8.)

b. Initialize the oscilloscope:

 Press save/recall SETUP.  Press the main-menu button Recall Factory Setup.  Press the side-menu button OK Confirm Factory Init.

c. Modify default settings:

 Press AUTOSET to obtain a viewable, triggered display.  Set the horizontal SCALE for the M (main) time base to 200 ms.  Press VERTICAL MENU.

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Brief Procedures

 Press the main-menu button Bandwidth; then press the side-menu

button 20 MHz.

 Press TRIGGER MENU.  Press the main-menu button Mode & Holdoff.  Press the side-menu button Normal.  Press CLEAR MENU to remove the menus from the screen.

2. Verify that the main trigger system operates: Confirm that the following

statements are true.

 The trigger-level readout for the main trigger system changes when

you rotate the trigger MAIN LEVEL knob.

 The trigger-level knob can trigger and untrigger the square-wave

signal as you rotate it. (Leave the signal untriggered.)

 Pressing SET LEVEL TO 50% triggers the signal that you just left

untriggered. (Leave the signal triggered.)

3. Verify that the delayed trigger system operates: a. Select the delayed time base:

 Press HORIZONTAL MENU.  Press the main-menu button Time Base.  Press the side-menu button Delayed Triggerable; then press the

side-menu button Delayed Only.

 Set the horizontal SCALE for the D (delayed) time base to 200 ms.

b. Select the delayed trigger-level menu:

 Press SHIFT; then press DELAYED TRIG.  Press the main-menu button Level; then press the side-menu

button Level.

c. Confirm that the following statements are true:

 The trigger-level readout for the delayed trigger system changes

when you rotate the general purpose knob.

 The general purpose knob can trigger and untrigger the square-wave

probe-compensation signal as you rotate it. (Leave the signal untriggered.)

4–12

TDS 420A, TDS 430A & TDS 460A Service Manual

Brief Procedures

Verify the File System

 Pressing the side-menu

button Set to 50% triggers the probe-com-

pensation signal that you just left untriggered. (Leave the signal triggered.)

d. V erify the delayed trigger counter:

 Press the main-menu button Delay by Time.  Press the side-menu button Events, just below the Triggerable after

Time selection.

 Use the General Purpose knob to enter an event count of 325 events.  Verify that the trigger READY indicator on the front panel flashes

about once every second as the waveform is updated on screen.

4. Remove the test hookup: Disconnect the standard-accessory probe from the

channel input and the probe-adjust terminal.

Equipment Required

Prerequisites None

One 720 K or 1.44 Mbyte, 3.5 inch DOS compatible disk (formatted).

1. Preset the digitizing oscilloscope controls: a. Insert the disk in the disk drive. b. Press save/recall SETUP. Press the main menu button Recall Factory

Setup; then press the side menu button Ok Confirm Factory Init.

c. Set the horizontal SCALE to 200 ms (one click clockwise). Notice the

horizontal readout now displays 200 ms at the bottom of the screen.

2. Verify the file system works: a. Press save/recall SETUP. Press the main menu button Save Current

Setup; then press the side menu button To File.

b. Turn the general purpose knob to select the file to save. Choose

TEK?????.SET. With this choice, you will save a file starting with TEK,

then containing five digits, and a

.SET extension. For example, the first

time you run this on a blank, formatted disk or on the Example Programs Disk, the digitizing oscilloscope will assign the name

TEK00000.SET to

your file. If you ran the procedure again, the digitizing oscilloscope would increment the name and call the file

TEK00001.SET.

c. Press the side-menu button Save To Selected File.

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4–13

Brief Procedures

d. Set the horizontal SCALE to 500 ms, and then use the vertical POSI-

TION knob to place the channel 1 baseline trace two divisions above

center screen.

e. Press the main menu button Recall Saved Setup; then press the side

menu button From File.

f. Turn the general purpose knob to select the file to recall. For example, if

you followed the instructions above and used a blank disk, you had the digitizing oscilloscope assign the name TEK00000.SET to your file.

g. Press the side-menu button Recall From Selected File. h. Verify that the digitizing oscilloscope retrieved the saved setup from the

disk. Do this by noting that the horizontal SCALE again reads 200 ms and the channel 1 baseline waveform is again vertically positioned near center screens as when you saved the setup.

3. Remove the test hookup: Remove the disk from the disk drive.

4–14

REV DEC 93

TDS 420A, TDS 430A & TDS 460A Service Manual

Performance Tests

This section contains procedures for checking that the TDS 400A Digitizing Oscilloscopes perform as warranted.

The procedures are arranged in four logical groupings: Signal Acquisition System

Checks, Time Base System Checks, Triggering System Checks, and Output Ports Checks. They check all the characteristics that are designated as checked in Chapter 1, Specifications. (The characteristics that are checked appear in

boldface type under Warranted Characteristics in Chapter 1.) You can use the form at the end of this section as a test record.

The procedures are arranged in four logical groupings: Signal Acquisition System

boldface type under Warranted Characteristics in Chapter 1.) You can use the form at the end of this section as a test record.

Read Performance Verification Procedures that start on page 4–1. Also, if you are not familiar with operating this digitizing oscilloscope, read Operating Information in Chapter 2 of the service manual or read the user manual before doing any of these procedures.

Prerequisites

STOP. These procedures extend the confidence level provided by the basic procedures described on page 4–5. The basic procedures should be done first, and then these procedures performed if desired.

The tests in this chapter comprise an extensive, valid confirmation of performance and functionality when the following requirements are met:

H The cabinet must be installed on the digitizing oscilloscope. H You must have performed and passed the procedures under Self Tests, found

on page 4–5, and those under Functional Tests, found on page 4–7.

H A signal-path compensation must have been done within the recommended

calibration interval and at a temperature within 5_ C of the present operating temperature. (If at the time you did the prerequisite Self Tests, the temperature was within the limits just stated, consider this prerequisite met.)

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Performance Tests

Equipment Required

T able 4–1: Test Equipment

Item Number and Description

H The digitizing oscilloscope must have been last adjusted at an ambient

temperature between +20_ C and +30_ C, must have been operating for a warm-up period of at least 20 minutes, and must be operating at an ambient temperature between 5_ C and +40_ C. (The warm-up requirement is usually met in the course of meeting the prerequisites listed above.)

These procedures use external, traceable signal sources to directly check warranted characteristics. The test equipment required is shown in Table 4–1.

Minimum Requirements Example Purpose

1. Attenuator ,10X (three required)

2. Attenuator , 5X (two required)

3. Termination, 50  Impedance 50 ; connectors: female

4. Termination, 75  Impedance 75 ; connectors: female

5. Cable, Precision Coaxial (three required)

6. Cable, Coaxial 75 , 36 in, male to male BNC

7. Connector , Dual-Banana (two required)

8. Connector , BNC “T” Male BNC to dual female BNC Tektronix part number

9. Coupler, Dual-Input Female BNC to dual male BNC Tektronix part number

10. Generator, DC Calibration

11. Generator, Sine Wave 100 kHz to at least 400 MHz. Variable

12. Meter, Level and Power Sensor

Ratio: 10X; impedance 50 ; connectors: female BNC input, male BNC output

Ratio: 5X; impedance 50 ; connectors: female BNC input, male BNC output

BNC input, male BNC output

BNC input, male BNC output 50 , 36 in, male to male BNC

connectors

connectors Female BNC to dual banana Tektronix part number

Variable amplitude to ±110 V; accuracy to 0.1%

amplitude from 12 mV to 2 V Frequency accuracy >2.0%

Frequency range:10 MHz to 400MHz. Amplitude range: 6 mVp-p to 2 V

p-p

Tektronix part number 01 1-0059-02

Tektronix part number 01 1-0060-02

Tektronix part number 01 1-0049-01

Tektronix part number 01 1-0102-01

Tektronix part number 012-0482-00

Tektronix part number 012-1338-00

103-0090-00

103-0030-00

067-0525-02 Wavetek 9100 (or , optionally,

Data Precision 8200, with 1 kV option installed)

Rohde & Schwarz SMY

Rohde & Schwarz URV 35, with NRV-Z8 power sensor

p-p

Signal Attenuation

Checking delay match between channels

Used to test Video Option 05 equipped oscilloscopes only

Signal Interconnection

Used to test Video Option 05 equipped oscilloscopes only

Various Accuracy Tests

Checking Trigger Sensitivity

Checking Delay Match Between Channels

Checking DC Offset and Measurement Accuracy

Checking Analog Bandwidth, Trigger Sensitivity , Samplerate, External Clock, and Delay-Time Accuracy

Checking Analog Bandwidth and Trigger Sensitivity

4–16

TDS 420A, TDS 430A & TDS 460A Service Manual

T able 4–1: Test Equipment (Cont.)

Item Number and Description

Performance Tests

PurposeExampleMinimum Requirements

13. Splitter, Power Frequency range: DC to 1 GHz. Tracking: >2.0%

14. Generator, Function Frequency range 5 MHz to 10 MHz. Square wave transition time 25 ns. Amplitude range: 0 to 10 V into 50

15. Adapter (four required) Male N to female BNC T ektronix 103–0045–00 Checking Analog Bandwidth

16. Adapter Female N to male BNC Tektronix 103–0058–00 Checking Analog Bandwidth

17. Probe, 10X included with

this oscilloscope

18. Generator, Video Signal Provides NTSC compatible outputs Tektronix TSG 1001 Checking Video

If available, items 11, 12, 13, and 15 can be replaced by a Tektronix SG 503 and SG 504. If available, a TG 501A may be used to check Sample-rate and Delay-time Accuracy. (A TM 500 or TM 5000 Series Power Module Mainframe is required.) If using a TG 501A, you may also need a 2X attenuator (50  BNC), Tektronix part number 011-0069-02.

A P6138A probe Tektronix P6138A Signal Interconnection

p-p

Rohde & Schwarz RVZ Checking Analog Bandwidth

T ektronix CFG280 Checking External Clock

Trigger Sensitivity

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Performance Tests

Test Record

Photocopy this page and the next page and use them to record the performance test results for your oscilloscope.

TDS 400A Test Record

Oscilloscope Serial Number: Certificate Number: Temperature: RH %: Date of Calibration: Technician:

Performance Test Minimum Incoming Outgoing Maximum

Offset Accuracy CH1 Offset +1 V

+10 V +99.9 V

CH2 Offset +1 V

+10 V +99.9 V

CH3 Offset +1 V (TDS 420A & +10 V TDS 460A) +99.9 V

CH4 Offset +1 V (TDS 420A & +10 V TDS 460A) +99.9 V

DC Voltage Measurement Accuracy (Averaged) CH1 100 mV –20.8 mV __________ __________ +20.8 mV CH2 100 mV –20.8 mV __________ __________ +20.8 mV CH3 100 mV (TDS 420A and TDS 460A) –20.8 mV __________ __________ +20.8 mV CH4 100 mV (TDS 420A and TDS 460A) –20.8 mV __________ __________ +20.8 mV Analog Bandwidth CH1 100 mV 424 mV __________ __________ N/A CH2 100 mV 424 mV __________ __________ N/A CH3 100 mV (TDS 420A and TDS 460A) 424 mV __________ __________ N/A CH4 100 mV (TDS 420A and TDS 460A) 424 mV __________ __________ N/A Time Base System Delay Between Channels N/A __________ __________ 450 ps Delta Time @ 20 ns (100 MHz) 9.7 ns __________ __________ 10.3 ns Long Term Sample Rate/

Delay Time @ 10 ns/100 ms

995 mV

9.935 V

99.2505 V 995 mV

9.935 V

99.2505 V 995 mV

9.935 V

99.2505 V 995 mV

9.935 V

99.2505 V

–1.5 Div __________ __________ +1.5 Div

__________ __________ __________

+ 1.005 V + 10.065 V + 100.5495 V

4–18

TDS 420A, TDS 430A & TDS 460A Service Manual

Performance Tests

TDS 400A Test Record (Cont.)

Oscilloscope Serial Number: Certificate Number: Temperature: RH %: Date of Calibration: Technician:

Performance Test MaximumOutgoingIncomingMinimum

Trigger System (DC Coupled Threshold) Main Trigger

Main Trigger — Falling Main Trigger

Delayed Trigger — Falling Auxiliary Trigger __________ __________ 10 MHz External Clock __________ __________ 10 MHz Probe Compensator Output Signal Frequency 950 Hz __________ __________ 1050 Hz Voltage 475 mV __________ __________ 525 mV

–18 mV –18 mV

__________ __________

+18 mV +18 mV

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4–19

Performance Tests

Signal Acquisition System Checks

These procedures check those characteristics that relate to the signal-acquisition system and are listed as checked under Warranted Characteristics in Chapter 1,

Specification.

Check Offset Accuracy

Equipment Required

Prerequisites See page 4–15.

Two dual-banana connectors (Item 7) One BNC T connector (Item 8) One DC calibration generator (Item 10) Two precision coaxial cables (Item 5)

1. Install the test hookup and preset the instrument controls: a. Hook up the test-signal source:

 Set the output of a DC calibration generator to 0 volts.  Connect the output of a DC calibration generator through a

dual-banana connector followed by a 50 W precision coaxial cable to one side of a BNC T connector (see Figure 4–4).

 Connect the Sense output of the generator through a second

dual-banana connector followed by a 50 W precision coaxial cable to the other side of the BNC T connector. Now connect the BNC T connector to CH 1.

4–20

Output Sense

DC Calibrator

Dual Banana to

BNC Adapters

Figure 4–4: Initial T est Hookup

Digitizing Oscilloscope

BNC T

50  Coaxial Cables

Connector

TDS 420A, TDS 430A & TDS 460A Service Manual

Performance Tests

b. Initialize the oscilloscope:

 Press save/recall SETUP.  Press the main-menu button Recall Factory Setup.  Press the side-menu button OK Confirm Factory Init.

c. Modify the default settings:

 Set the horizontal SCALE to 1 ms.  Press SHIFT; then ACQUIRE MENU.  Press the main-menu button Mode; then press the side-menu

button Hi Res.

 Press DISPLAY.  Press the main-menu button Graticule; then press the side-menu

button Frame.

 Press MEASURE.  Press the main-menu button Select Measurement for CHx; then

press the side-menu button Mean. (You will have to press MORE several times to access the Mean measurement.)

 Press CLEAR MENU.

2. Confirm input channels are within limits for offset accuracy: Do the

following substeps — test CH 1 first, skipping substep a since CH 1 is already set up to be checked from step 1.

WARNING. High voltages are used in this procedure. Before doing this or any other procedure in this manual, read the Safety Summary found at the beginning of this manual.

a. Select an unchecked channel:

 Press WAVEFORM OFF to remove the channel just confirmed

from the display. Then, press the front-panel button that corresponds to the channel you are to confirm.

 Press MEASURE.  Press the main-menu button Select Measurement for CHx; then

press the side-menu button Mean. (You will have to press MORE several times to access the Mean measurement.)

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4–21

Performance Tests

T able 4–2: DC Offset Accuracy

Vertical Scale Setting

1mV 0 +1 V +1 V ±5mV 100 mV 0 +10 V +10 V ±65 mV 1V 0 +99.9 V +99.9 V ±649.5 mV

Vertical Position

Offset Setting

Generator Setting

Offset Accuracy Limits

b. Set the vertical scale: Set the vertical SCALE to one of the settings

listed in Table 4–2 that is not yet checked. (Start with the first setting listed.)

c. Set the offset: Press the VERTICAL MENU button and then the Offset

main-menu button. Using the General Purpose knob, set the offset as dictated by Table 4–2. (Start with the first setting listed.)

d. Set the generator: Set the DC calibration generator to match the vertical

scale as dictated by Table 4–2. (Start with the first setting listed.)

e. Check against limits: Do the following subparts in the order listed.

 Subtract the measured mean from the generator setting. The result is

the offset accuracy

 CHECK that the offset accuracy is within the limits listed for the

current vertical scale setting.

Check DC Voltage

Measurement Accuracy

(Averaged)

 Repeat substeps b through e until all vertical scale settings listed in

Table 4–2 are checked for the channel under test.

f. Test all channels: Repeat substeps a through e for all input channels.

3. Disconnect the hookup: a. Set the generator output to 0 V. b. Then disconnect the cable from the generator output at the input

connector of the channel last tested.

Equipment Required

Prerequisites See page 4–15.

Two dual-banana connectors (Item 7) One BNC T connector (Item 8) One DC calibration generator (Item 10) Two precision coaxial cables (Item 5)

4–22

TDS 420A, TDS 430A & TDS 460A Service Manual

1. Install the test hookup and preset the instrument controls: a. Hook up the test-signal source:

 Set the output of a DC calibration generator to 0 volts.  Connect the output of a DC calibration generator through a

dual-banana connector followed by a 50 W precision coaxial cable to one side of a BNC T connector (see Figure 4–5).

 Connect the Sense output of the generator through a second

dual-banana connector followed by a 50 W precision coaxial cable to the other side of the BNC T connector. Now connect the BNC T connector to CH 1.

Performance Tests

Output Sense

DC Calibrator

Dual Banana to

BNC Adapters

Figure 4–5: Initial T est Hookup

b. Initialize the oscilloscope:

 Press save/recall SETUP.  Press the main-menu button Recall Factory Setup.  Press the side-menu button OK Confirm Factory Init.

c. Modify the default settings:

50  Coaxial Cables

Digitizing Oscilloscope

BNC T

Connector

 Press SHIFT and then ACQUIRE MENU.  Press the main-menu button Mode; then press the side-menu button

Average 16.

 Press DISPLAY.  Press the main-menu button Graticule; then press the side-menu

button Frame.

TDS 420A, TDS 430A & TDS 460A Service Manual

4–23

Performance Tests

 Press MEASURE.  Press the main-menu button Select Measurement for CHx; then

press the side-menu button Mean. (You will have to press MORE several times to access the Mean measurement.)

 Set the vertical SCALE to 100 mV.  Press the VERTICAL MENU button and then the Offset main-

menu button. Set the offset to 0 V.

 Set the vertical POSITION to 0 V.

2. Confirm input channels are within limits for DC delta voltage accuracy: Do

the following substeps — test CH 1 first, skipping substep a since CH 1 is already selected from step 1.

a. Select an unchecked channel:

 Set the generator output to 0 V.  Press WAVEFORM OFF to remove the channel just confirmed

from the display.

 Press the front-panel button that corresponds to the next channel you

are to confirm.

 Press MEASURE.  Press the main-menu button Select Measurement for CHx; then

press the side-menu button Mean. (You will have to press MORE several times to access the Mean measurement.)

 Move the test hook up to the channel you select.  Set the vertical SCALE to 100 mV.  Set the vertical POSITION to 0 V.  Press the VERTICAL MENU button and then the Offset main-

menu button. Set the offset to 0 V.

b. Set the generator: Set the DC calibration generator to +0.35 V. c. Record Measurement: Read the mean at the measurement readout, and

record this number on a piece of scratch paper.

4–24

d. Set the generator: Set the DC calibration generator to –0.35 V.

TDS 420A, TDS 430A & TDS 460A Service Manual

Performance Tests

e. Check against limits: Do the following subparts in the order listed.

 Use this formula to calculate voltage measurement accuracy.

700 mV – (mean from step c – (present mean))

For example:

700 mV – (347 mV – (–358 mV)) = –5 mV

 CHECK that the voltage measurement accuracy is

within 20.8 mV.

f. Test all channels: Repeat substeps a through e for all channels.

3. Disconnect the hookup: a. Set the generator output to 0 V. b. Then disconnect the cable from the generator output at the input

connector of the channel last tested.

Check Analog Bandwidth

Equipment Required

Prerequisites See page 4–15.

One sine wave generator (Item 1 1) One level meter and power sensor (Item 12) One power splitter (Item 13) One Female N to Male BNC Adapter (Item 16) Four Male N to Female BNC Adapters (Item 15) Two 50  precision cables (Item 5) Two 10X attenuators (Item 1).

1. Install the test hookup and preset the instrument controls: a. Initialize the oscilloscope:

 Press save/recall SETUP. Then press the main-menu button Recall

Factory Setup.

 Press the side-menu button OK Confirm Factory Init.

b. Modify the default settings:

 Press TRIGGER MENU.  Press the main-menu button COUPLING; then press the side menu

button Noise Rej.

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4–25

Performance Tests

 Press SHIFT; then ACQUIRE MENU.  Press the main-menu button Mode; then press the side-menu button

Average 16.

 Press Measure. Now press the main-menu button High–Low Setup;

then press the side-menu button Min–Max.

Sine Wave

Generator

Output

Digitizing Oscilloscope

Figure 4–6: Initial T est Hookup

NOTE. Refer to the Sine Wave Generator Leveling Procedure on page 4–55 if your sine wave generator does not have automatic output amplitude leveling.

c. Hook up the test-signal source:

 Connect the sine wave output of a sine wave generator to CH 1 (see

Figure 4–6). Set the output of the generator to a reference frequency of 10 MHz or less.

 Set the horizontal SCALE to 50 ns. (If using a reference other than

10 MHz, adjust the horizontal SCALE to display 4 to 6 cycles of the waveform.)

4–26

2. Confirm the input channels are within limits for analog bandwidth: Do the

following substeps — test CH 1 first, skipping substeps a and b since CH 1

is already set up for testing from step 1. a. Select an unchecked channel:

 Press WAVEFORM OFF to remove the channel just confirmed

from display.

 Press the front-panel button that corresponds to the channel you are

to confirm.

 Move the leveled output of the sine wave generator to the channel

you select.

TDS 420A, TDS 430A & TDS 460A Service Manual

b. Match the trigger source to the channel selected:

c. Set the input impedance of the channel:

d. Set the vertical scale: Set the vertical SCALE to one of the settings

T able 4–3: Analog Bandwidth (TDS 420A)

Performance Tests

 Press TRIGGER MENU.  Press the main-menu button Source.  Press the side-menu button that corresponds to the channel selected.

 Press VERTICAL MENU; then press the main-menu

button Coupling.

 Press the side-menu button  to toggle it to the 50 W setting.

listed in Table 4–3 (TDS 420A) or Table 4–4 (TDS 430A and TDS 460A) not yet checked. (Start with the 100 mV setting.)

Vertical Scale Reference Amplitude Horizontal Scale Test Frequency Limits

100 mV 600 mV (6 divisions) 5 ns 200 MHz ≥424mV

1 V 500 mV 2 V (4 divisions) 5 ns 200 MHz ≥1.414 V 200 mV 1.2 V (6 divisions) 5 ns 200 MHz ≥848 mV 50 mV 300 mV (6 divisions) 5 ns 200 MHz ≥212 mV 20 mV 120 mV (6 divisions) 5 ns 200 MHz ≥84 mV 10 mV 60 mV (6 divisions) 5 ns 200 MHz ≥42mV 5mV 30 mV (6 divisions) 5 ns 200 MHz ≥21 mV 2mV 12 mV (6 divisions) 5 ns 150 MHz ≥8.4 mV 1mV 6 mV (6 divisions) 5 ns 95 MHz ≥4.2 mV

If the oscilloscope does not trigger in step 2e, change the trigger coupling to DC for this Vertical Scale setting.

2 V (2 divisions) 5 ns 200 MHz ≥1.414 V

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4–27

Performance Tests

T able 4–4: Analog Bandwidth (TDS 430A and TDS 460A)

Vertical Scale Reference Amplitude Horizontal Scale Test Frequency Limits

100 mV 600 mV (6 divisions) 2 ns 400 MHz ≥424mV

1 V 500 mV 2 V (4 divisions) 2 ns 400 MHz ≥1.414 V 200 mV 1.2 V (6 divisions) 2 ns 400 MHz ≥848 mV 50 mV 300 mV (6 divisions) 2 ns 400 MHz ≥212 mV 20 mV 120 mV (6 divisions) 2 ns 400 MHz ≥84 mV 10 mV 60 mV (6 divisions) 2 ns 400 MHz ≥42mV 5mV 30 mV (6 divisions) 2 ns 400 MHz ≥21 mV 2mV 12 mV (6 divisions) 2 ns 250 MHz ≥8.4 mV 1mV 6 mV (6 divisions) 2 ns 100 MHz ≥4.2 mV

If the oscilloscope does not trigger in step 2e, change the trigger coupling to DC for this Vertical Scale setting.

2 V (2 divisions) 2 ns 400 MHz ≥1.414 V

e. Display the test signal: Do the following subparts to first display the

reference signal and then the test signal.

 Press MEASURE; then press the main-menu button Select

Measurement for CHx.

 Now press the side menu button more until the menu label Pk-Pk

appears in the side menu (its icon is shown at the left). Press the side-menu button Pk-Pk.

 Press CLEAR MENU.  Set the sine wave generator output (if necessary, use 10X attenua-

tors) so the CHx Pk-Pk readout equals the reference amplitude in Table 4–3 (TDS 420A) or Table 4–4 (TDS 430A and TDS 460A) that corresponds to the vertical scale set in substep d.

 Press the front-panel button SET LEVEL TO 50% as necessary to

trigger a stable display.

f. Measure the test signal:

 Increase the frequency of the generator output (leveled output) to the

test frequency in Table 4–3 (TDS 420A) or Table 4–4 (TDS 430A and TDS 460A) that corresponds to the vertical scale set in substep d.

4–28

 Set the horizontal SCALE to 5 ns (TDS 420A) or 2 ns (TDS 430A

and TDS 460A).

 Press SET LEVEL TO 50% as necessary to trigger the display.

TDS 420A, TDS 430A & TDS 460A Service Manual

Read the results

from the readout of

measurement Pk-Pk.

Set the generator

frequency to the test

frequency from

tables 4–3 and 4–4.

Performance Tests

 Read the results at the CHx Pk-Pk readout, which automatically

measures the amplitude of the test signal. (See Figure 4–7.)

Set the horizontal

scale from the tables.

Figure 4–7: Measurement of Analog Bandwidth

g. Check against limits:

 CHECK that the Pk-Pk readout on screen is within the limits listed

in Table 4–3 (TDS 420A) or Table 4–4 (TDS 430A and TDS 460A) for the current vertical scale setting.

 When finished checking, set the horizontal SCALE back to the

50 ns setting (the setting you used in step 1b.

STOP. Checking the bandwidth of each channel at all vertical scale settings is time consuming and unnecessary. You may skip checking the remaining vertical scale settings in Table 4–3 (TDS 420A) or Table 4–4 (TDS 430A and TDS 460A) (that is, skip the following substep, h) if this digitizing oscilloscope has passed

the 100 mV vertical scale setting just checked in this procedure and passed the Verify Internal Adjustment, Self Compensation, and Diagnostics procedure found under Self Tests, on page 4–5.

TDS 420A, TDS 430A & TDS 460A Service Manual

4–29

Performance Tests

NOTE. Passing the signal path compensation confirms the signal path for all vertical scale settings for all channels. Passing the internal diagnostics ensures that the factory-set adjustment constants that control the bandwidth for each vertical scale setting have not changed.

h. Check remaining vertical scale settings against limits (optional):

 If desired, finish checking the remaining vertical scale settings for

the channel under test by repeating substeps d through g for each of the remaining scale settings listed in Table 4–3 (TDS 420A) or Table 4–4 (TDS 430A and TDS 460A) for the channel under test.

 When doing substep e, skip the subparts that turn on the CHx Pk-Pk

measurement until you check a new channel.

 Install/remove 10X attenuators between the generator leveled output

and the channel input as is needed to obtain the six division reference signals listed in the tables.

Check Delay Match

Between Channels

i. Test all channels: Repeat substeps a through g for all channels.

3. Disconnect the hookup: Disconnect the test hook up from the input

connector of the channel last tested.

Equipment Required

Prerequisites See page 4–15.

One sine wave generator (Item 1 1) One precision coaxial cable (Item 5) One 50  terminator (Item 3) One dual-input coupler (Item 9)

STOP. DO NOT use the vertical position knob to reposition any channel while doing this check. To do so invalidates the test.

1. Install the test hookup and preset the oscilloscope controls: a. Initialize the front panel:

 Press save/recall SETUP.

4–30

 Press the main-menu button Recall Factory Setup.  Press the side-menu button OK Confirm Factory Init.

TDS 420A, TDS 430A & TDS 460A Service Manual

Tektronix TDS 460A, TDS 430A, TDS 420A Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Service Manual

Table of Contents

Specifications

Operating Information

Theory of Operation

Performance Verification

Adjustment Procedures

Maintenance

Options Electrical Parts List Diagrams Mechanical Parts List

List of Figures

List of Tables

General Safety Summary

Service Safety Summary

Preface

Manual Structure

Manual Conventions

Related Manuals

Introduction

Before Servicing

Strategy for Servicing

Tektronix Service

Product Description

General

User Interface

Signal Acquisition System

Horizontal System

Trigger System

Acquisition Control

On-Board User Assistance

Measurement Assistance

Storage

Display

Nominal Traits

W arranted Characteristics

Performance Conditions

Typical Characteristics

Installation

Supplying Operating Power

Operating Environment

Applying and Interrupting Power

Repackaging Instructions

Installed Options

Operating Information

Screen Layout

Basic Procedures

Theory of Operation

Logic Conventions

Module Overview

Performance Verification Procedures

Brief Procedures

Self Tests

Functional Tests

Performance Tests

Prerequisites

Equipment Required

Test Record

Signal Acquisition System Checks