Two Apple TVs. One going, the other not. Why?

I have 2 Apple TVs. One 720 the other 1080. The 720 is working fine and will operate at either TV.

The 1080 will not work at either TV.

I go to set it up and I get all the screens including passwords, itunes account etc, but cannot get on to my network.

The DNS.Router, Password etc settings are identical on both Apple TVs.

I tried all avenues using my wi fi connected to my Apple TVs, to no avail.

Trouble shooting from Apple and from Forums I have followed all the advice.

Currently I am downloading as per instructions from my Mac Book Pro via micro USB.

It has been running for two hours or more, still shows another 13 hours to run. BTW I do have ADSL 2 Broadband which is usually quite fast for anything else to download.

Several times I have done this as after several hours it pops up the message "Cannot Contact Server at this time".

So I start again.

Also going through the check list from the iTunes Help on the tool bar, I am getting a message "Take to Apple for Service".

My guess is that the Apple TV is faulty and needs to be either replaced or serviced.

Alhough I do not know how this could be done as it seems to be a solid "puck" like device and completly sealed.

My 720 Apple TV has been performing without fault since new, I can upgrade my iTunes each time a new one comes out (the latest one is installed) or a new IOS from Apple is installed (currently IOS 10.8.2 Mountin Lion).

Apple TV is a great add on for my computer and home entertainment, but I am sick of wasting my time trying to work through this glitch...