"The issue I have is Tech support keeps sending me back to the well with "just one more thing" to test before we know for sure. That is not good customer service."
Sorry you had this experience, but I am glad to hear that your issue is resolved.
As a service professional who manages a large field and technical support team for electrical mechanical equipment (not saw stop), I can say some days you get the bear and some days the bear gets you. It would have been great if the techs caught the issue on the first call, but some days the magic wand does not work well. I would be remiss, however, in not pointing out some exceeding good support you got:
1. The techs did not just start throwing parts at your issue, but actually wanted to identified the specific issue. It would have been very easy for them to have you start replacing components, especially with an intermittent problem. I know they did not get the resolution as fast as you would have liked.
2. The techs documented the troubleshooting they did and reviewed it before recommending a new course of action.
3. The techs spent a significant amount of time over several days supporting you at no charge even though: (1) you were not the original purchaser of the equipment and (2) the tool was not under warranty. This level of support is very, very rare. Try calling a major car manufacturer or you computer manufacture and asking them to walk you though several hours of troubleshooting support on a used, out of warranty piece of equipment.