The original rotary knob is quite worn. This is a rubber piece that is bonded to hard plastic underneath. This rubber can seperate in time so we're going to replace it with a 3d printed knob

Note: I don't see how this repair/modification would affect the waterproof status of the radio. I guess if you wanted you could put a tiny dab of silicone on the screw before you put it back in but it doesn't look like Yaesu did anything like that from the factory. Just know that you are attempting this repair/modification at your own risk