I got the Partial Signal loss when both tuners were tuned to a Dish channel on my 722.
All I had to do was bring up the Guide and then Cancel. That brings the picture back. There was no loss of signal on the channel I was watching. I could rewind and there was no loss.
Anyone else having a problem where you can't record on two OTA channels? I had a case the other day where I wanted to record 4 events. 2 on the Sat tuners and 2 on the OTA and I didn't get one of the OTA feeds.