So far, Al's controller is the only one that I know of that has had this problem.  Not unit specific because it has happened on 3 different EC2s in Al's plane so I have concluded that it is something unique to his installation.   I'd like to get to the bottom of it and any other reports would be helpful.

Small point, Tracy, but we’ve actually seen the issues on just 2 EC2 units; the original and the current. But even then it would certainly suggest it is not specific a given ‘box’.  The one intermediate box in which you had switched the internal connection on the temp sensor, to save me the trouble, never got past finding the transmit RFI problem, so never determined whether there was corruption of settings.  The connecting PCM and EM2 are still the same.

The really puzzling (and frustrating) thing is that we have had the scope on every pin on the EC2 connector, and, after eliminating a couple potential noise issues, we saw nothing that could explain why it is happening.  So the investigation continues. If someone else sees similar behavior, it might provide a clue.

Al (perfect weather conditions today, and the plane was ready to go – but at the last moment I decided I wasn’t.  Guess I’m fighting some holiday bug. Bummer.)