OK, total brain cramp. Went back to the transformer. Original install is two cables each connected to the feed at the transformer source. He then split the casing and ran the two wires to the fixtures. That way no connections in the ground.
The wire you see coming in from the left, is the wire that was the problem. In my earnestness, I pulled the wire and you can see it separated. Not sure how I could have put enough force on it to rip the wire. I'm not that strong.
So now the issue is this. The remaining wires feed a fixture I know works. Why the continuous wire from the transformer failed in the sheathe is a mystery.
Thinking two options. One dig the main feed back enough to strip the sheathe and do a splice.
Or go to the fixture that works and splice the feed there
The sprinkler is just that, a line we capped when we put in the fountain.