I agree with Simply Quilting - check the wiring, it's easy to get replacement wiring harnesses. Even my computerized machine isn't truly 'grounded' (aka no three prong . . . check what you are using now). And often there are three-prong outlets in homes but they aren't wired or aren't wired correctly. I have only changed out the motor on one of my old machines.

You do realize that the cherry red machines have been repainted??