Instead of going with "the batteries are bad for sure" why not at least charge them and see how long they last a few times. This will work for the transmitter but not for the reciever unless you're going to sit there for an hour+ moving the sticks with the servos hooked up... in fact with no load on them you still can't tell for sure on the rx. Not 7 years but I have batteries that sat for 5+ years and are still good.