I can not be of any direct help as I don't own one ....yet.... they are on my short list. I can only parrot what others have said in that they are Very "tight" tolerance and it does not take much to lock them up. looking at the bobbin hook area and taking the hook out and checking behind are different things...... before taking anything apart though I would definitely try some High quality oil ( tri flow or even ATF ) on all of the lube points and see if she spins free with the belt off.. it almost sounds as though you have an issue with the hand wheel clutch area......good luck I think it is a solvable problem and should be a Very good machine when you find it.