My mother is having trouble with her machine. This was a wedding gift to her from my father, and will someday be mine. The problem is: the upper thread is constantly breaking, like every couple of inches of sewing. Mom showed me how to do a thorough cleaning and oiling on the machine, but this did not help the thread breaking problem. I tried new needle and thread but no help.
I know that the spring in the upper tensioner is shot. I suspect replacing that spring will solve the problem. Is there anything else that I should be looking at?