Safety switches were fine it was the breaker forth shed. 

  The varistor still tested fine and there were plenty of machines on the same circuit so im ruling out lighting strike.

   So they do just die from old age that's what I was hoping.  Thanks Mike.  Just didn't want to install another and blow boards or anything like that as every board are original with all matching serial numbers

   Thanks for the replies I'll go buy another tomorrow and see how I go