I have an older 85046A test set with the original logic board (85046-60001) and a mechanical transfer switch. I was fine with this (I thought), but upon connecting it to my 4396B combination analyzer, the analyzer does not seem to recognize that the test set has a mechanical (vs solid-state) switch. Immediately upon conclusion of any two-port calibration, the test set starts switching back and forth between forward and reverse, once a second. This happens even if all I am displaying is S11. The only way to prevent the instrument from eventually destroying itself is to use one-port calibrations only.
This NA is of similar vintage to the 8753, although designed in Japan. I know that the 8753 is smart enough to detect the transfer switch type, and if mechanical, it makes compromises to not keep switching continuously. Does the 4396B not support this? I'm a bit upset as I just paid $$ for the test set and nowhere in the 4396B documentation did it mention a solid-state switch was required for two-port operation.
My 4396B has the latest firmware, version 1.16. Apart from this issue, everything else works and I am getting good data.