Tektronix 1502C - page 104

Appendix C: Operator Troubleshooting

C–41502C MTDR User Manual

At power on during initialization only.

The instrument expects the pulse height to be slightly less than two major

divisions high and adds gain to make the pulse exactly two divisions high. This

message indicates that the pulse is non-existent, too small, or that the gain

circuitry is not working correctly.

If there is no pulse after pushing the MENU button, no measurements can be

made. Have the instrument repaired.

If the pulse is there and less than two divisions high, you probably can make

useful measurements. Run the Offset/Gain Service Diagnostic.

Refer the instrument for repair. If the instrument passes, use the SET VERT REF

to make the pulse exactly two divisions high. The instrument’s front-end board

needs repair, but it is often possible to make measurements.

ERROR: Acquisition Initialization

TYPE: Initial Pulse Height > 2 Divs at 0 dB

At power on during initialization only.

The instrument expects the pulse height to be slightly less than two major

divisions high. This message indicates that the pulse is greater than two divisions

in amplitude with no additional gain added.

This message usually means that the front-end board pulse circuitry is no longer

properly terminated. If the waveform does not change when a 50 W terminator or

cable is attached, the internal cable or front-panel connector is probably

disconnected or broken and no measurements can be made until they are

repaired.

If the waveform does respond normally when a 50 W terminator or cable is

connected, the failure might be in the gain circuitry on the Main board or in the

hybrid circuit.

Have the instrument repaired. If a pulse is present, distance measurements can be

made. If the pulse is more than two divisions high, the millirho scale is not

calibrated and loss measurements should not be made.

ERROR: Acquisition Initialization

TYPE: Vertical Scale failure

Occurrences:

Meanings:

Remedies:

Message:

Occurrences:

Meanings:

Remedies:

Message:

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