i have dropped my 396 twice the first time it bent the knob and the second straighten it out.
when you turn it, it can jump forward or backward and skip over other settings, meaning it jumps two or three times.
it will be going in for service soon as it is a great radio still.
i usually don't change anything, so it is good for now.
you might think of making it a base and hook it up to a computer if it is really bad.