OK, will check that out. If it is the TVS. it looks like something I could replace. Do you recommend the 1.5KE36CA? If my local source doesn't have that one would you go to a 33 or to the higher 39?
It still bothers me that there was nothing that happened on the track that I could perceive that would cause the failure. Will chalk it up to within the normal reliability failure rate. As mentioned by others, if it fails open I wouldn't know it anyway.