The channel I keep the box on most of the time (RTVN on G19) suddenly stopped working normally. There is no picture or sound, but the signal quality is about 70, and if I record (either manual or scheduled) it plays back fine. This is on just one channel, all my other channels (even on the same transponder) work normally. I had not changed any setting recently, and the identical box next door (on the same dish, dual LNB) is still working. What could possibly cause that?