Apple TV 3 no signal

My apple TV3 worked fine on my Hitachi plasma TV for more then 8 months.

Last week I had a problem streaming from Netflix, this happened before and the solution was to unplug the apple TV let it restart and all would be fine.

But when I done this now I got no signal error.

I went to the apple store and they done a full reset on my apple TV and told me it would work, but no same problem.

I have been reading on the support sites but non of the solutions work for me.

I have seen more posts on this error but none are giving me a solution or clear answer on how to solve this.