Arnie, Ed Hooten in Athens Ga.
I have the same problem with my DELTA. I pop the switch pull the connections a few time and off we go. Happens occassionally - you may already have an answer
If not, pop the switch out (POWER OFF) pull the connections and while their off, wouldn't hurt hit the contacts with fine sandpaper.
Keep Scrolling
Rooten, Tooten, Scooten Ed Hooten