Our antenna motor still works and it will raise but won't come down unless you tap it on top. It seems to hang up on the lower section
Seems like you need to replace the motor..
I'd say the mast is broken, the nylon part of the mast that is inside the motor. You would need to purchase a new mast, remove the old and open the motor up to help remove the broken pieces. There are DIY's online...http://www.antennamastsrus.com/Instructions%20Mast.htm
Search Lincoln Mark VIII Questions
Lincoln Mark VIII Experts