I am also having a similar problem with my Delta 40-694 scroll saw. The difference is that the saw will turn on, run for several seconds and then stop. I followed this thread and replaced the breaker, so that is brand new. I also by-passed the starter switch and the saw will turn on, run for a few seconds and then cut off again. I also pulled the brushes and cleaned them off. They are not worn very much so I did not replace. As long as I keep resetting the breaker, I can get the machine to run for awhile until it cuts off again. Could this possibly be the $200 controller board? The speed control works okay but the saw runs a little longer on slower speeds. If I run at full speed the saw will cut off sooner. Any suggestions? The saw does not get heavy use. I contacted Delta and their warranty is almost completely useless because they do not have my registration on their system and I need the receipt. I purchased this on-line and no longer have the info.
