I have remotes that operate the TV-Tuner-Dish-VCR-VCR-DVD. Yesterday all at once none would operate their units. I set 15' from the units. I replaced batteries for the TV and nothing happened. I can operate all units from their buttons. None of the remotes are set to operate units other than their own. I turned the power off to all for a 12 period with no change other than, some could be turned on from 6', but might not turn off.