Well, Cocoonut, I have read this advice before in other blogs. This time I followed your suggestion exactly and was able to figure out that the phase coupler was not going to fix my problem. Fortunately I have a detailed map of my 96 (give or take) breakers and was able to work backwards after turning them mostly off (light in utility room and computer stayed on).
I left the microwave for the last as my suspicions grew ... and sure enough it was the microwave (embarrassing since this has been pointed out many times). I installed a ZNF10A-P (Simply-Automated) Noise Filter and was able to conclusively demonstrate that it solved the major problem. I still have an issue with my workshop lights, but with microwave issue nailed I can at least communicate with my 3 workshop switches when the lights are off. Not ideal but workable for now. I have a ZNF10A-W and will have to figure out where to install it.
Many thanks to you and Desert-AIP for pushing me in the right direction.
I left the microwave for the last as my suspicions grew ... and sure enough it was the microwave (embarrassing since this has been pointed out many times). I installed a ZNF10A-P (Simply-Automated) Noise Filter and was able to conclusively demonstrate that it solved the major problem. I still have an issue with my workshop lights, but with microwave issue nailed I can at least communicate with my 3 workshop switches when the lights are off. Not ideal but workable for now. I have a ZNF10A-W and will have to figure out where to install it.
Many thanks to you and Desert-AIP for pushing me in the right direction.