My living room and guest room TV’s are on cable (Comcast), my bedroom TV has a converter. All of them are pixalated messes. The converter box worked well the first day but has been very erratic since, sometimes the picture screws up, sometimes it goes to ‘weak signal’, sometimes a station disappears altogether. I might write it off to the indoor antenna but the cable picture keeps messing up too. It has that frozen pixillated jumping and sound interruption. What is going on?