I am new to this forum but I wanted to share my experiences with a DS series motored mount.
First I want to say thank you to MistrBadgr for his write up on how to take apart the mount. I would have had a hard time without this knowledge.
So my problem is that my mount worked great except the azimuth would not rotate. You could hear the motors spinning but the mount would move a faction of a degree. When I opened up the mount I did not see anything out of the ordinary. So I lubricated all the parts and put it back together. As I was putting it back together I noticed it could spin so I decided to spin it 360 degrees. As I was doing so I noticed that it was catching on something in the rotation. So I took the unit apart and saw that the metal mount arm of the motor/gear assembly was rubbing against the outer can. I took a metal file and filed down all the areas where I could see scratches. Once I had done this a few times the unit freely rotated without catching. I put everything back together and it spins fine now! I have noticed other people list this problem so if you cannot figure out what is wrong check to make sure that the motor mount arm is not rubbing against the outer can casing.
Also in MistrBadgr's instructions he talks about using a string to pull the worm gear assembly back so that the "can" can fit into place. I was able to achieve this by just pushing down on the assembly and it snaps into place without problem.