It is powered from DC mains via a fuse block in the dash area. Plus, from above, via N2K.
Please don’t shoot me for the wiring hygiene - I DO plan to redo the dash
We cast no aspersions on your wiring, we have seen much much messier installs 
If you can do easily, we would suggest disconnecting the D/C positive connection for power (either by physically removing the inline or by switching/turning off at the breaker. It would be useful to know if the unit is fully connected on N2K and the easiest way to do that is to remove screw terminal power and see if it stays powered up.
I’m not in front of it now, but - yes - it DID stay powered (from the N2K connection) when I disconnected power. I mentioned this back in September above.
Ok, next time you are on the vessel it would be helpful if you can fully power cycle the unit and then power it from N2K (i.e. remove/depower both screw terminal and N2K connections, wait a few seconds, and then reconnect/repower only the N2K connection).
If that doesn’t resolve data coming in on the N2K side then we are almost certainly dealing with a hardware issue (and we’ll send you out a replacement).
Sorry for the inconvenience, but looking forward to getting this resolved.
Ok - I just did that. Running on N2K only now. Any change?
That does seem to have reset things successfully:
We will keep monitoring at this end.
OK. I see that I’m missing Battery information - I also disconnected that input and it’s not picking up N2K batteries (not a big deal). I’m happy to keep it powered via N2K.
What I WOULD like is the rest of that trip data from September 10. Should I assume that now that it’s syncing again that the trip data is lost?
Sorry to be late on this, we are checking today …
So, the good news is that everything does seem normal since that November 16th reset. That’s all looking great.
We went back to the archives for your data and forced the generation of a trip for all data available between September 8th and 11th. Not sure there is any more in there than the previously (automatically generated trip), but it is definitely everything that was available.