I thought I'd toss this out and see if anyone can help. I've got a Raymarine 12V autopilot linear drive that I bought used. The electric motor seems to work fine, and it moves the arm in and out, sorta, but there's no force behind the movement. You can stop it easily with your hand, your finger even. So... I decided to see what makes it tick. As I pulled the arm out of the tube, a few tiny BBs went flying. It appears the drive consists of a screw driven by the electric motor, and an inside threaded arm, with small BBs completing the mechanical connection between the screw and the thread. Beyond that I haven't looked any deeper into what's going on in that screw mechanism. Can anyone explain the engineering here, and the problem? Think it needs more BBs? thanks, Mike
