Tektronix 1502C Appendix C: Operator Troubleshooting

1502C MTDR User Manual C–1

Appendix C: Operator Troubleshooting

For assistance in troubleshooting, use the following flow chart to determine if

you have a simple problem you can fix or if the instrument needs to be sent to a

Tektronix Service Center.

Use this process to determine whether the instrument should be repaired or is

OK to use when you have a problem.

CAUTION: Any time the instrument smells hot, repeatedly blows fuses, or

repeats the same error message, you should have the instrument serviced by

qualified technicians using the procedures in the 1502C Service Manual.

These are the first checks you should perform when you think you might have a

problem with the instrument.

The first step asks you to preset the instrument controls. Here is how to do that:

Set Vp to .66; turn the IMPEDANCE knob all the way counterclockwise; turn the

FILTER knob all the way counterclockwise, then back two clicks; turn the

DIST/DIV knob all the way counterclockwise, then back three clicks; turn the

PULSE WIDTH knob all the way counterclockwise; remove any accessories that

might be plugged into the Option Port (e.g., chart printer), and disconnect any

cable that might be attached to the front-panel connector.

To complete the tests, you might need a Volt-Ohmmeter (VOM), a flat-bladed

screw driver (to set the line voltage switch) and possibly, some spare fuses.

When you have completed these tests, you will know that it is safe to use the

instrument or that it needs repair or adjustment internally. You do not remove

the case for these tests.

IMPORTANT: It is possible for the instrument to continue to make some

measurements even after reporting an error message. Do not ignore repeated

error messages! They indicate something is wrong and should be used with the

1502C Service Manual troubleshooting procedures.

This procedure will give you confidence that the instrument is functioning

properly. It is not an exhaustive set of tests that guarantee that the instrument

meets all specifications and is perfectly calibrated. The calibration procedures in

the 1502C Service Manual are the best method for assuring that the instrument

meets all specifications.

Contents

Main Page WARRANTY Contacting Tektronix Table of Contents Page List of Figures Page Page Page General Information Installation and Repacking Unpacking and Initial Inspection Repacking for Shipment Power Source and Power Requirements Page Page General Safety Summary Safety Terms and Symbols Page Page Page Operating Instructions Overview Powering the 1502C Handling Care of the Battery Pack Battery Charging Low Battery Low Temperature Operation Preparing to Use the 1502C 1502C Tektronix Operating Instructions 161502C MTDR User Manual Display Figure 14: Display and Indicators Front-Panel Controls Menu Selections Main Menu Page Page Page Test Preparations The Importance of Vp (Velocity of Propagation) Finding an Unknown Vp Operating Instructions 1502C MTDR User Manual 113 Figure 17: Vp Set at .66, Cursor at Reflected Pulse (Set Correctly) Figure 15: Vp Set at .30, Cursor Beyond Reflected Pulse (Set Too Low) Figure 16: Vp Set at .99, Cursor Less Than Reflected Pulse (Set Too High) Cable Test Procedure Distance to the Fault Page Page Reflection Coefficient Measurements Return Loss Measurements Ohms-at-Cursor Using VIEW INPUT How to Store the Waveform Using VIEW STORE Using VIEW DIFF Page Page Using Horizontal Set Reference Page Using Vertical Set Reference Vertical Compensation for Higher Impedance Cable Page Page Additional Features (Menu Selected) Max Hold Pulse On/Off Single Sweep Page Operator Tutorial What is the Tektronix 1502C? How Does It Do It? You, the Operator Menus and Help Getting Started Page Page The Waveform Up Close Page A Longer Cable Ohms-at-Cursor Page Page Noise Page Set Ref (Delta Mode) HORZ SET REF Page VERT SET REF Page VIEW INPUT STORE and VIEW STORE Page VIEW DIFF Menu-Accessed Functions Max Hold Page Pulse On / Off Single Sweep Page TDR Questions and Answers Page Page Options and Accessories Option 04: YT-1 Chart Recorder Option 05: Metric Default Option 07: YT-1S Chart Recorder Power Cord Options Test Data Record Option Option DE Optional Accessories Accessories Standard Accessories Options and Accessories 1502C MTDR User Manual 33 Page Appendix A: Specifications Electrical Characteristics A21502C MTDR User Manual Table A1: Electrical Characteristics (Cont.) 1502C MTDR User Manual A3 Environmental Characteristics Table A2: Environmental Characteristics A41502C MTDR User Manual Certifications and Compliances (continued next page) 1502C MTDR User Manual A5 Physical Characteristics Table A3: Physical Characteristics Page Appendix B: Operator Performance Checks Equipment Required Getting Ready Power On Metric Instruments Set Up 1. Horizontal Scale (Timebase) Check Page Page 2. Vertical Position (Offset) Check 3. Noise Check 4. Offset/Gain Check 5. Sampling Efficiency Check 6. Aberrations Check 7. Risetime Check Page 8. Jitter Check Conclusions Appendix C: Operator Troubleshooting Appendix C: Operator Troubleshooting C21502C MTDR User Manual Operator Troubleshooting (with cases on) Error Messages Message: Occurrences: Meanings: Message: Remedies: Page Page Page Appendix D: Application Note Pulse Echo Testing of Electrical Transmission Lines Using the Tektronix Time-Domain Reflectometry Slide Rule Terms and Symbols Relationships VSWR vs. Percent Reflected Voltage Return Loss (dB) vs. Percent Reflected Voltage Appendix D: Application Note D41502C MTDR User Manual Percent Reflected Voltage vs. Characteristic Line Impedance Figure D3: Slide Rule 50 ohm Source +1r = W+.03r = 53.1W Appendix D: Application Note 1502C MTDR User Manual D5 Percent Reflected Voltage vs. Load Resistance Characteristic Line Impedance or Load Resistance vs. Reflection Amplitude (as seen on your TDR) Centimeters vs. Inches or Meters vs. Feet Dielectric Constant vs. Velocity Factor Time vs. Short Distances, in Centimeters or Inches Time vs. Long Distances, in Meters or Feet Page Glossary Page Page Page Page Page 1502C MTDR User Manual Index1 Index A B C D I L M N O Q R S T U