We have a 311 that we use in our RV. It is often disconnected from power for as much as two to three months. I moved it into the house last month for use with a second TV as we weren't planning on using the RV. It works fine in the house and always powered. Last week I unplugged the receiver from AC and left it for ten days. When I reconnected power sure enough it had lost authorization again. Is there a memory "keep-alive" button cell in these receivers that can go bad or is this just how it is when your receiver is disconnected from power for any length of time?