Dear Dave and WeatherCat Davis station troubleshooters,
So much for Davis Tech support!
Thanks for your own reports . . . Yes, indeed Davis instruments are very miserly about power so they can run on amazingly small amounts of power.
So, time for a new theory.
Yes, indeed and there one more piece of information that suggests an alternative. There is a fellow on the WXForum complaining about ISS circuit boards with problems with the power switching circuitry. There has to be some logic that switches from the solar panel, to the super capacitor, and finally to the battery if there is no other source of power. If that logic is working incorrectly, like for example not switching to the battery early enough, then the ISS would shutdown.
It may well be the case that my long cable run to my temperature/humidity probe may require a bit more current than usually expected. Eventually my old ISS circuit board had its super-capacitor fail. After all, it is 5 years so. What I have tried to replace with are newer boards with updated firmware. I wonder if these newer boards cannot handle that additional current draw properly and are not using the battery quickly enough.
However, that gives me another sneaky idea. It turns out that the 6382 transmitter is exactly the same circuit board as the as the ISS transmitter. However, it has no solar panel and thus presumably never uses the super-capacitor. I'll see if I run into problems with my temperature/humidity probe plugged into that. If I don't, I might just buy a second one of those and use that as my ISS transmitter instead something with the solar panel. Right now I replace the 123 battery 4 times a year on the 6382 transmitter. If I can make my present setup work with just that change, I'll gladly pay Herb his battery commission and get rid of this super-capacitor nonsense completely.
For now I'll just keep monitoring the situation and see what happens. I just hope nothing goes haywire during the rain event we are expected starting this weekend.
Cheers, Edouard