Just an update on the situation. What I did was move the controller upstairs to where I knew it would be on a different side of the electrical panel (other phase). As I suspected it started controlling the modules that had quit respopnding, and stopped controlling the modules that did respond. This tell me that the signal coupler which I had been using had failed.(the 3 prong dryer type) Rather than purchase another signal coupler, I will purchase another CM15A and program identically. I believe this is the easiest and least expensive way to keep everything operating as it should. Now if anyone has a way of bench testing the coupler I would be willing to try that and possible affect a repair. I haven't opened it up yet but I doubt it's too complicated. Even at that, I think that the two seperate CM15A will probably produce a better signal since neither phase will have to travel throughout the entire electrical system.