I have 2 TT devices, a 630 where the TMC works perfectly and a 710 where the TMC doesn’t work at all.
It says that the TT RDS-TMC Receiver is connected, but the green button never become green, just searching for a signal all the time.
I tried x20,x30,x40 and x40 modes, and lots of different navcores
I have had a lot of problems with the TMC receiver on the X10 series, And I have never had any problems on the XL and one Units, Exactly how you described it, continually searching for signal. Hope you manage to sort it out
Try 8.562, I found it the most stable version on my GO 710. Except for the dummy TMC bar problem (it is there when the device is on the car holder and the TMC antenna is not connected), everything works, including TMC, Bluetooth hands-free, auto day-night mode etc.