Troubleshooting the VNA


By running a few checks, you can identify if the analyzer is at fault. Before calling Keysight Technologies or returning the instrument for service, please make the following checks.

Other Support Topics

Check the Basics

A problem can often be solved by repeating the procedure you were following when the problem occurred. Before calling Keysight Technologies or returning the instrument for service, please make the following checks:

  1. Is there power at the power socket? Is the instrument plugged in?

  2. Is the instrument turned on? Check to see if the front panel line switch and at least one of the LED rings around the test ports glows green. This indicates the power supply is on.

  3. If you are experiencing difficulty with the front-panel keypad or peripherals, the USB bus may be overloaded. Remove the USB devices, restart the VNA, and reconnect the USB devices. See Power-up.

  4. If other equipment, cables, and connectors are being used with the instrument, make sure they are connected properly and operating correctly.

  5. Review the procedure for the measurement being performed when the problem appeared. Are all the settings correct?

  6. If the instrument is not functioning as expected, return the unit to a known state by pressing the Preset key.

  7. Is the measurement being performed, and the results that are expected, within the specifications and capabilities of the instrument?

  8. If the problem is thought to be due to firmware, check to see if the instrument has the latest firmware before starting the troubleshooting procedure.

  9. Check that the measurement calibration is valid. See Accurate Measurement Calibrations for more information.

Check Error Terms

If you print the error terms at set intervals (weekly, monthly, and so forth), you can compare current error terms to these records. A stable, repeatable system should generate repeatable error terms over long time intervals, for example, six months. If a subtle failure or mild performance problem is suspected, the magnitude of the error terms should be compared against values generated previously with the same instrument and calibration kit. See the procedure for monitoring error terms.

Consider the following while troubleshooting:

Error Log

Some VNAs create automatic log of data for troubleshooting purpose. The log file stores data related to the total power ON time, number of times of power ON, results of power ON test and so on. For security reasons, if this data needs to be deleted, then SERVice:LOGGing:CLEar command can be used to clear the log recorded by the instrument.