All of a sudden I can no longer change channels with IR remote or manually on my HR20. I have tried 3 different remotes, same problem. Also did a manual reset, a RBR reset and the good old unplug the receiver reset and still have problem. All other functions on remote and receiver seem to work fine. Channel changing will not work at all. Do not know if I need to call for a replacement unit or not. I really like the one that I have but not if it is not working right.Any thoughts would be greatly appreciated ????????