It's not the receiver.
It's the cable or the LNB
Go to your dish and figure out which two cables serve the main floor and MARK THEM.
Swap the two pairs of cables; connect the two main floor cables to the two LNB outputs serving the basement, and vice-versa.
Did the receiver problems stay with same receiver, or switch?
If the main floor receiver is still acting up, you have a cable problem.
If the basement receiver is now acting up, and the main floor receiver is working properly, you have an LNB problem.