Not sure why you have your brick wired in series to Fixed and Variable inputs
Fixed 1 is all you require sine you’re using one power source, and it’s not variable.
unless there is some requirement to the Legacy System…
I would connect the Z-4000 TRACK 1 to FIXED INPUT 1 and TRACK 2 to FIXED JNPUT 2 and use the Brick to power your legacy
Even if you were running your TIU in passive mode-which is not recommended because it bypasses the TIU Emergency Stop function-there’s no reason to run feeders in series to both the Variable and Fixed inputs
The FIXED1 is the required input, and subsequently that makes FIXED OUTPUT 1 required, also