Apple Tv not connecting

I have recenlty bought a new time capsule and have 2 apple tv's. Once I set up the new wireless network, all of my apple stuff (2 X Macbook Pro, 2 X Iphone, Ipad) all connected with no problem. One apple tv (newer generation 1080p) worked straight away, but my other (720p) will connect to the network but not to the internet. I have tried all of the basics (restarting everything, running network as unprotected, manual input of ip address, refress of DHCP leases) and have had no luck. This is extremely frustrating as I would have thought having an Apple Time Capsule as my base station would have made this integration seemless. Any help???