I have an Velodyne F 1200 servo sub from 1994. I love the sub...it is perfect for my bedroom system. This past weekend I was adjusting the volume (wanted a little more bass) and when I turned the volume knob, I heard a lot of static. There was only a few places on the volume dial when I could actually hear the sub. I think the contacts need to be cleaned but I am not sure. Anyone have any ideas? Thanks in advance.