I built one circuit and tested it for several months and it work great. This week I built 20 circuits, all on the same perforated breadboard. Each circuit works correctly, as per the attached diagram, during construction and testing. When I turn the system full on there appears to be several types of interaction problems. i.e. As an example, each group of four (from the same Digitrax DS-64) has some form of interaction. That is the LED does (or may) not change color and the other three lights flash or change colors. i.e. It appears one circuit will work OK but when I add two or three circuits the panel will not function correctly. The power supply I am using is an I.T.E. Power Supply model T481208003CT 12VDC 750 ma. ANY HELP WOULD BE GREALTY APPRECIATED.