Are you saying that it didn’t work using the TIU fixed input 1, but did work using a Z1000 on the aux power port?
That’s pretty much it. Before I got the WiFi, the only power to the TIU would have been through Fixed 1. After adding the WiFi, that was putting power to the TIU as well.
Since this arrangement worked just fine for years and I always had 10’s the whole way around my layout when I’d check the signal, I guess I didn’t really think I needed to do it any differently.
Something must have occurred either when I disconnected my TIU to try my son’s on my layout or when I reconnected. I have no idea what that something was but, given how tired and frustrated I was, it would not be a shock if I screwed something up without knowing.
In any event, the addition of the external power sources solved the problem on both my layout and my son’s. We had an early morning father / son train running session this morning before he and his fiancée headed to the mountains for the day.