The AirPort (WiFi) module will be embedded into the logic board. Replacing the Logic Board will be a snap. I haven't attempted to look under the cover of the logic board, but I highly doubt ( but not impossible ) it's replaceable.
1: Change out your remote battery ( CR 2032 ) just in case. 2: Press MENU & DOWN arrow buttons simultaneously till the indicator light flashes rapidly. 3: Release both buttons. - Your AppleTV will restart and continue the boot sequence.