I have a Pro95. If I don't use it for awhile, it does the same thing. You need to do some surgery. If you're comfortable doing it:
Take the radio apart, and get to the keypad. You need to remove one or two ribbon cables as you go along. It's not a tough job, just go slow, don't be in a hurry. As you take it apart, make a note on how the shim that goes behind the display goes. It's angled and if you don't pay attention, it can be a dickens to orientate back the way it was. I got my shim marked with a sharpie which way is which.
When you get to the keypad, wipe all the fingers and the pads they land on with alchohol and a q-tip. Put it back together and it should scan again. It don't seem that this would cause it not to scan. And when you clean up all the pads and fingers, they don't appear dirty. But it fixes it every time. At least a half dozen times thru the years.