"Bucephalus" wrote in message
...

Nothing was changed before the Start circuit started acting up. I
hadn't
even taken the lid off the circuits box since this was wired 20
years
ago. Something failed on its own. And, yeah, the Start switch is
numbered 3 and 4. I presumed it was some sort of breaker causing the
problem, but the schematic doesn't even show them.


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Bucephalus

What changed was that contacts eroded and the machine vibrated.

I finally found a reference to manually closing the contacts to check
them. Watch the red plungers in the center of the contactors when you
press the start button.
http://www.hvachowto.com/2014/10/02/...ys-contactors/

--Marengo