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Bernie:

I did check that connector in my airplane, it is in the center console. But, as I mentioned earlier, the fault in my case was the disconnect button. I suppose yours could be bad as well, in an intermittent fashion. Might be worth checking if it fails again...

Steve

Steve- I asked my avionics guy about the disconnect button but he thinks the connector is more likely. However, if it fails again that's where we'll go next. I did notice that I can get the failure mode (P and R illuminated with dashes) if I hold down the autopilot disconnect after disconnecting the autopilot. However, we're not sure if that's normal or telling us something. Bernie

I've never seen the (P-R-dashes) failure mode after disconnecting the autopilot with the red button, but I have to admit I never held it down for a prolonged time, just a momentary push. I will try that next time I'm at the hangar.

Steve, it wasn’t clear from your posts if you also had electric trim failure or just failure of the autopilot to complete the pretest cycle. I am having the same issues as Bernie (no electric trim and no A/P after stage 3). Andrew at Diamond Customer Support says not an unusual problem but the failure of the electric trim was new to him, and he thought that if the electric trim was not getting power this could be the culprit.

Nick: If your autopilot fails the preflight test, the electric trim will NOT work. I would definitely check the continuity of the disconnect buttons (both, since they are in series), either by connecting your laptop as a dumb terminal, or by simply working the switches loose and using an ohmmeter.

If it is the disconnect button, the fix is easy and cheap (see my earlier post).

Steve

Same comment, stupid, it's the temperature! Less of a problem here in Bahamas, but when flying further north, trim failure on startup, and normally works later in flight, once sun heats the rear fuselage. Quick fix, if you have one handy, blow a hair dryer on the servo for 3-4 minutes. Had it in 2 shops, they could not fix the root problem....

Steve, thanks so much for that. If I had your competence with matters electrical it would be a fun weekend project, but since changing lightbulbs is my limit I need to find a Steve locally. I will let the group how it works out. I admire you Wolfgang, but not likely a temperature issue in the South of France in June.

I agree, there may be different contributing factors, and different causes. From observation I can only say, in my case it must be temperature. And, I mean, not freezing, but anything under 10-15 centigrade can get it stuck.

The annual is being done next week at the Diamond factory and I will report how they sort it out. In the meantime I have learned more than I ever thought about NKK DPDT switches. The joys of plane ownership. But keeps you young. Thanks guys.

Reporting back as promised. This is the message from the Factory in Austria:

“We did a software update on the Configuration Modul and adjust the Roll Servo….now it works fine!”

When I pick the plane up in a couple of days we’ll see if it “works fine” but I am a litte skeptical since no one has mentioned software update issues.