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.

Copyright  T ektronix, Inc. All rights reserved.
T ektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes

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.

Table of Contents

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

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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

ii

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. . . . . . . . . . . . . . . . . . .

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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

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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. . . . . . . . . . . . . .

vi

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.

ix

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.

x

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

xi

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

xv

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

1

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

2

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:

1

Resolution

Clock, External:

Resolution

 8 8 0.5 Log

HiRes

 8 8 0.5 Log

HiRes

timediv



2

500  10



2

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

BW

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

3

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 



2

100

HiRes

 0.44



Hz



timediv

50



Hz

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

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