Should I swap the Power board from another machine and see if problems still occurs, if so buy a new updated version from Bay area for 299 us?
I think it's time you sought some professional help from a local repairman. Replacing boards 'willy nilly' is a waste of time and money.
I am sure it is a reasonably easy fix but it seems you don't have the technical ability to sort the problem.
Best to ask a pin repairer to call and you might be surprised how inexpensive it is to repair.
