I have read in other threads on DCS forum that some clubs feed TMCC signal to each TIU output. That would shorten signal path for those blocks not now getting signal directly (meaning all but the one). Will try that with a soldered wire harness to deliver signal to all four outputs, next. If that doesn't solve, plan to remove all but one of the new 12 gauge common power feed wires from system and try one block that way. The new wires are the last thing changed. Thanks for the ideas, please keep them coming.