Crowfly - thanks for the heads up. With some miinor differences your
description matches mine exactly. Several days ago, I posted the
problem to the IPACS site but they have not responded. I will be
chasing them today. There are a number of complaints on their
forum about USB connection reliability (even for the old AFP) so
don't think that we are experiencing a new problem.

Believe that the components that they have in the USB cable are
failing after some amount of use. Thinking it might be a heat
problem after it failed one time, I even put the cable assembly
in the freezer for a while to see if that would change anything but
it didn't. Still couldn't get it to recalibrate until I waited for several
hours.
Many thanks for t he contact, will keep in touch.
Bruce