My Advanced HDPVR 630 really doesn't work as it was designed to. In fact, it is so bad that it can't even give us a good picture when it has a strong signal.
From the sounds of it, I'm really quite lucky because my signal strength is consistently between 89-94, but even then my picture pixelates! Just to make sure, I've replaced cables, checked connections, etc..., but to no avail.
To call the machine "Advanced" seems like an oxymoron considering it's list of problems. Like so many others who have complained on this site, mine suffers from all the usual problems (crashing, unable to record, unable to playback, poor picture quality when playing back, etc.....), and it burns me up that I paid $350 for it.
I've been on the phone with tech support several times, and sadly I'm left unsatisfied.