[chirp_devel] UV3R Plus problem

This may well be a faulty radio, but I will ask here just in case I am missing something subtle.

I own a UV3R Plus, works fine, programs ok with CHIRP - I will call this my "original" radio.

I have just purchased from EBAY a shiny new UV3R as a second radio.

I can plug the original radio into the laptop and program it with no problems, if I then unplug the cable and plug it into the new radio it fails to work (No ACK). I have tried re-starting CHIRP, I even tried the manufacturer software, nothing seems to make it work.

Do I need to do something to prepare the new radio or is it just faulty ?

Thanks, Jon