I am trying to replace my battery powered ring camera with a ring pro 2 hard-wired camera. My first issue is my doorbell is an intercom system and therefore I don’t have a doorbell transformer. I brought 120v to the transformer from a nearby switch in a way that assures uninterrupted power. I measured voltage at the transformer and I have 120v there but when I hook it up, there’s no voltage on the terminals on the back. Ring tech support thinks it’s the transformer, but this is the second one with the same issue. Does any know of a reason why I can’t get power out of the transformer with known 120v going in?