Pixelation Is The Samsung Box Responsible

Its not like the pixelation you get when you have a weak signal and audio problems its more like a pulsating pixelation which covers about 3/4 of the screen at the same time but no sound problems but happens when i record stuff,the first SA box that i had didnt have any of those problems until the hard drive failed after 18 months,the freeview through the antenna doesnt seem to have this pixelation either and i have reformatted this samsung box twice and still the same.:mad: