Have the same model and problem and I fixed one problem only to encounter another. Answer to your problem is the inside shaft rubber belt is missing . However, you can go to Harbor Freight and buy the "O Ring" set and make your own rubber belt. You need to open the unit (2 screws on bottom) and find the shaft end on the left side. Remove the two bolts on top that support the motor assembly (Watch out for the washers & remove fan cover 3-screews)) -Pull motor aside, but do not separate. Undo the rear shaft pulley (2 tiny Allen screws), fish it out...you will install 3 smaller o rings and then install 2 more orings (next size up) on top and one larger one to the left (6 total) The larger o ring is used for forward and comes in contact with the large metal that will turn the spindles. When in reverse, the smaller o rings will come in contact with the smaller silver rotating shaft. I don't know of any parts, so o rings seem to do the trick!
However, inside the spindle arm in front there is also a belt with teeth and mine is completely powderized and have yet to see if a belt is available. good luck in your repair!
Kevin, October 2017