Well the fix was easier than I thought. The tipping bucket had shifted on it’s axis so that the magnet didn’t pass the reed switch any more. Apparently there’s supposed to be a plastic pin on each side that holds the bucket in the center. One of these had broken off and had been replaced by a piece of string tied around the shaft by the previous owner. Until yesterday this had been working fine for the two years I’ve owned the station. I retied it and added a bit of super glue to hold it in place.