I have not replied to this thread, but it makes me go hmmm...
How are you connecting the receivers to the TVs? Of course, you will want the HD picture. If you are connecting the boxes to your TV via HDMI, then try component cables along with composite audio cables (red and white, not the yellow one). If those do not work, you may want to try just the composite cables just to see if you still have problems.
Are you connecting your boxes to a phone line or Internet? If so, you may want to try to disconnect them. At a family member's, connecting the boxes to the Internet was actually not helping. If you do not have them connected and can easily do so, you may want to just give it a try. I have heard that updates from the boxes come from them being connected to the phone or Internet.
I hope that helps. I usually hear good things about the 722.
Otherwise, could it be a problem with the installation?
I do have to admit that it can be frustrating when issues like this occur. We did not have technical issues with Dish so far, but we did with D*. After the contract was done, we switched to Dish.