Troubleshooting RF based Remote Control (Roku)

[cmccul002]

Greetings all,

 I have a few Roku Premier boxes that have RF based remotes. Each remote pairs with its own box. I hove one remote that stopped working. I cannot get it to pair with any of the boxes. I can pair the other two remotes to any of the boxes, but none of the boxes see this one remote.

Changed batteries, tried pairing to other boxes - no go. Was able to pair another remote to this box. 

EDIT:  Actually it seems these remotes may not be RF but use WiFi instead.

I took the remotes board out, and of course nothing looks odd.  How would one troubleshoot an RF remote?