My 622 has done this twice. I disconnect the power, reconnect and run "test" in the install menu. The 622 comes back on line. It must be a software issue with the 622.
I don't know the cause, but I think it was E*'s problem and was not on my end. I lost all three birds, it was 70 degrees outside, and my 622 internal temp was 108.
With me, when 129 was down and I switched to a channel on the 129 satellite, I'd get a blank screen (then going back to channels on 110 & 119 satellite had blank screen too) and the box re-boots and stays at 'progress 0' indefently. A 'check switch' would show I lost the 3 satellite's. I found tuning to a channel on 110 satellite and re-booting brought back 110 and 119.
i lost it and freaked thinking my LNB had finally died
I do have some HD on 61.5 coming in but 119 and 110 took a dump
I went to check the signal Q and got a' searching for satellites' which I had never seen before