According to some reports, Apple has acknowledged an issue with some third-generation Apple TV units and their wifi.
Here’s what Apple’s internal note to its stores and authorized resellers said about the wifi issues:
Apple has determined that a very small number of Apple TV (3rd generation) products might experience one of these Wi-Fi related connectivity issues: Cannot locate network, Unable to join network, Dropped or intermittent connection.
Apple will replace the unit for free if a technician determines that it’s defective. The replacement is offered up to two years after the purchase date.