I have a Case branded FM-750 that am trying to get Rangepoint RTX to work on. 

And no this is not because of the Satellite 138 issue.   I'm just wanting to try try Rangepoint to see if it is a worthwhile improvement for me over WAAS for general tillage work.

I have obtained a 3 day trial unlock code and have successfully unlocked.  But the 750 will not converge on RTX.  It stays on WAAS and never achieves enough accuracy for the signal meter in the upper left of the screen to go green.  On the menu that displays status it reports "RTXCN:  Searching" and flashes back and forth occasionally with "RTXCN: Idle".   I take it it is not receiving data.

Any suggestions?