The Supernanogan was on overnight quietly. FC6 went in this morning. (Didn't check if fingers were involved.) I  now notice a strange pulsing in our Stripchart. See what you think. Note: field and A/q max scales are orders of magnitude higher than real life.

Later...At around 14:00 I added ferrite cores to the field probe cable at the CANbus interface box. That clipped the high side of the pulses completely. If I play very carefully with the field range, I can get small artifact-looking pulses to appear since I installed them (see 17:16 chart). In the meantime, I found that, contrary to appearances, the field stability program was not really regulating. A remote reboot of the server cured it.