Time to check for tight fittings or cable damage. Might want to try another coax cable, just in case. Do you have another source, such as OTA, to ensure that the TV connected to TV1 is not the problem?
If all is well with the above, may we have a moment's silence for the late, great, 322. Dish will send a replacement, but it will be refurbished. Considering there are no moving parts, these things are very reliable.