I have two loops running on a Post War ZW. One loop is on the A-U terminal then through a TVS to the track and the other loop is on the D-U terminal through the TVS to the track. I have my Legacy connected to the outside track of the lower and upper loop. Everything works fine. When I phased my Z transformer (accessories) by connecting a wire from the U terminal on the ZW to U terminal of the Z and it killed the Legacy signal to the upper loop and not the lower loop. I am perplexed. Any reason for this. Thanks
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I can only imagine that you have something connected that were not hearing about. Typically, you only have to connect the TMCC/Legacy signal to a single point that is the common for all the outside rails and you're good.
It would also be helpful to know exactly how big the layout is and how the two transformers are wired.
I assume that everything, track power, accessories, and the legacy are using the same common ground? Or do you bring the legacy ground(s) from the upper and lower level back to the transformer. If it were me, I would experiment. I would run a temporary wire between the outside rail on the top loop (the one not working) to the outer rail of the lower one, and see if you see the signal. Another option would be to run a temporary wire from the upper loop to the U on the ZW, and see if that helps. I don't know how, but it almost sounds like the ground from the upper level for legacy is being lost (I know, captain obvious).Another option is instead of running a wire between the U of the ZW to the U of the Z, run a wire from the common ground bus (I assume you are using a common ground bus with the track and accessories and legacy return) to the Z U terminal and see what happens.
The only other thing I can think of is the Z somehow through its ground plug when the two U posts are connected is putting noise into the house ground that is interfering enough with the legacy signal that goes over the house ground that it is making the signal too weak on the upper loop (I am not an engineer, far from it, and if GRJ laughs at this, well, I prob deserve it, my dad is probably spinning in his grave)
It is totally wired right. Both loops are running on the same transformer. The only time there is a problem is when I hook up the common of the ZW to the common of the Z. I think you are right that some sort of interference is coming from the Z transformer. Nothing else really explains it. Thanks
I'd check the continuity of the secondary of the Z transformer to the power plug contacts. The one thing that can nuke the TMCC/Legacy signal is connecting the track to earth ground! If there is any continuity at all from the primary of the transformer to the secondary, CEASE USING THE TRANSFORMER IMMEDIATELY!
Have you tried temporarily swapping the same accessories currently powered by the Z, so that they're instead connected to either the B or C channels on the ZW to see what would happen to the Legacy signal on the upper loop? If it works, this would eliminate the accessories as a potential cause.
If that works as expected, then maybe see what happens when you reconnect those accessories back to the Z and then run a temporary 3 prong drop cord from one of the house outlets around either the inside or outside of the upper loop tunnel. Given the available info, this doesn't seem like it would make a difference, but could help narrow down the issue.