I just replaced my received that was installed by the installer and had trouble with from day one. The new one appears to be better. The picture looks better. And so far channel 5 is coming in without cutting out, pixelating, blacking out.
It sure took a lot of aggrevation to get DirecTV to replace the receiver.
As a customer who spends lots of money with DirectV they should be more respectful and responsive of customer's needs.
It is very possible that the receiver that was installed was defective.