wireless touchpanel not talking

First thing, go into the setup and make sure RF is turned on. They can be set to IR only, and there is a strong possibility you got it that way.

Another possibility, if the RF is already on, is the radio board was swapped at some time and is no longer the same frequency as indicated. Something I do regularly when swapping old Viewpoints out, since I have a limited stock of loaners that I repeatedly repair when a customer has an issue and aren't ready to upgrade, is swap the boards when changing the panel. It's just a little plug-in daughter board near the IR window. Of course, after a lot of that, one has no idea what the the real frequency is if you aren't careful to mark it (which sometimes gets neglected).

That said, 418 is the standard frequency, and it's a bit of a stretch to assume a board got swapped ... so you can't rule out your receiver, by sheer unlucky coincidence, went bad also.