Just got my HD DVR today from DirecTV. Everything looks great (even SD locals look better than they used to) but for some reason I have slight flicker on Discovery HD Theater. I thought maybe it was just one show, but it's all of them. It's not a huge flicker, but it is enough that it hurts your eyes. I'm thinking it's not a problem with my TV since everything else looks fine. Any ideas why this is happening?