After checking everything for condition and security, and the voltage regulator for operation within specification, I figured that I had electrics fixed, but no, it quit again today after 30 minutes of flying.
There was only one thing I had not checked, as there really is no way to check it visually - the overvoltage sensor. It turns out, that some very long time ago, long since forgotten, I had anticipated such a failure, (someone must have suggested it to me!). After some thought, I recalled having installed a hidden switch for this situation. Sure enough, up under the panel, there was a switch which shorted out (bypassed) the live leads of the overvoltage sensor. By switching the switch, I removed the overvoltage sensor from the circuit, and it worked just fine, Unless the voltage goes over!
New overvoltage sensor on order!
So, with that worked out, and the test flying of the day as complete as the day would allow it to be, I got in to fly home. As I taxiied out, I could feel tickling in my ear, I lifted my headset, and rubbed my ear, A minute later it was tickling again. This time I had a better look. A large hornet had taken up residence in the headset, and was walking around. Ooooo, that would have hurt!
I wonder what should I unexpect next?