Yesterday my PIP stopped working on my 522 in single mode. One tuner works fine as in I can watch TV normally and all other TV's in the house work. When I push PIP however I get a blank screen. When I swap the PIP it goes into searching for satellite and continues that forever without ever finding a signal. The signal is fine in the other original swapped out PIP box. Basically I don't get a signal in both boxes. Any idea what is happening?