I'm trying to figure out using Atlas 205 connector to turn power on/off to blocks. All the wiring diagrams I've seen show power in, 1 lead (hot) and power out 1 lead to block. Blocks have insulating pins on center rail. No other wires. However, I can't get the controller to turn power off. (checked out operation to ensure connector switch works - it does). There is obviously something about the grounding that I'm missing. I have ground buss to my layout, trains run ok. What am I missing?