Agilent Technologies HP 8719D Service Manual page 256

If you detect problems using error term analysis, use the following approach to
isolate the fault:
1. Check the cable by examining the load match and transmission tracking
terms. If those terms are incorrect, go to "Cable Test".
2. Verify the calibration kit devices:
Loads: If the directivity error term looks good, the load and the test port
are good. If directivity looks bad, connect the same load on the other test
port and measure its directivity. If the second port looks bad, as if the
problem had shifted with the load, replace the load. If the second port
looks good, as if the load
port.
Shorts and opens: If the source match and reflection tracking terms look
good, the shorts and the opens are good. If these terms look bad while the
terms
rest of the
had
not been the problem, troubleshoot the first
look good, proceed to "Verify Shorts and Opens".
Accessories Troubleshooting 9-3
I