How many times a day does it do this? Sounds like interference from a neighbors remote. If it only happens once a day, it is just your nightly update.
I don't think a bad LNB could cause a rec. to turn on and off.
If its not the above reasons I listed,your rec. is probably going bad.
A bad LNB can cause you to lose signal,but that doesn't turn off power to the box.
My 722 was spontaneously rebooting too recently. Called Dish and they thought it may be inconsistent power because the receiver checked out as good through the diagnosis screen. Told me to change outlets and that did not help. I got to thinking that it may be due to some erroneous timers. I recently downgraded my service from Gold to Bronze and I still had some timers set for channels I no longer received. I deleted those timers and voilà! Problem solved - no more spontaneous reboots.
my 622 started doing the same thing yesterday. It'll shut down like it has overheated or something - then reboot, scan sats and come back on - but never stays on for more than 15 mins before doing it all again
constant rebooting is caused by the DVR losing power. Tech support will want you to retest the DVR plugged into a different outlet, and not in a surge protector or power strip but directly into a wall outlet.
I've been through this with several refurb DVR's this past Fall. My opinion is they have something failing in the power supply. This could be triggered by excessive heat too but if that is not the case, then power is the main culprit. A failing hard drive can also overload the power supply if the HD electronics is failing causing reboot.
I have noticed the 522 doing it recently but not the 722, both connected to the same outlet. Guess I see having a replacement one sent AGAIN in the near future. I now see the 522's on the list along with the 501/508 as problematic receivers.