MDShunk Moderator Join Date: Jan 2007 Posts: 1,823 ——————————————————————————– I’d say you’ve welded the dry contacts in relay #1 by some means every once in a while. (possibly the same overcurrent situation that is taking out the diode). Have you checked the current draw on a recording basis, and compared it with the rating of the relay? Since relay #2 is unaffected, I think it’s safe to say that D1 isn’t the issue. Now, on the other hand, if relay #1 only failes to drop out when relay #2 is powered, then I’d guess that you have a “leaky” diode on your hands, passing enough holding current the wrong direction to keep relay #1 closed even after its contact is opened.