unit recently quit working, after trouble shooting I determined the problem was the "O" Ring that connects the drive motor
to the antenna
assembly. It appears that you can no longer get this part from Raymarine
. In my search on the web one poster indicated it was 4" O-Ring that could be purchased from Amazon or Ebay. However, I would think that you would need to know both the inner and outer diameter to find the proper O-Ring. Looking for any help in locating a replacement "O" Ring.