Back again....
Thanks for all your help so far.
This T5 is not mine but been asked to see if I can get it working.
It refused to bind to known good RX.
So I put together a small spectrum analyzer. "just like that".
No output from the T5 aerial, no output from the RF board.
Scoped the input signal to the rf board, all correct as far as I can tell.
Voltage regulator correct.
Knowing that spares for these transmitters are nil, has anyone replaced the RF board with another type?
Dave