Remove connection to FieldTR primary (RL2)
Remove RL2; probing on the bus side of the transformer could potentially
damage the board.
Removing RL2 will remove the possibility of diagnosing errors on the
transformer, but those are not frequent (no transformer error in 10
years and hundreds of nodes has been reported; check here [1] the list
of all WorldFIP related errors [1]; a FielDrive has been found faulty
twice, but so far there is no FieldTR error reported).