I sawed the pipe in half just upstream from the tinkling sound. This was not exactly where the restriction was, but it was close.
I was able to use two joined sections of 3/4 pvc pipe to ramrod the obstruction. A lot of muddy water flowed out, for a long period, before it cleared. Repaired the cut section with a 6" rubber coupling and things are better. Flow in this section at least doubled.
I still don't have proper flow at the very end of the pipe. I will need to search for and find more obstructions down the pipe.
