I am having an issue with my cable box and new Pioneer VSX 21 TXH. Every time I turn on the cable box the Hi Def channels that I know broadcast in 1080 are showing on the box as 720. I go through the procedure to switch it to 1080 as the Comcast tech guy told me to do. It works fine until I turn the box off for the night. The next day everything is broadcasting in 720 again. Has anyone ever experienced something like this? Not sure if it is a cable box problem or has something to do with the A/V receiver.