Don’t worry about that picture, it will work it is just the most complicated way to flip 2 wires by flipping all 4. Works just the same. You are in the ballpark with the voltage.
Take the belts off and see if you have any issues. Then it is either the the belt tension or binding on a rail, or both. Did you start with all the tension bolts loose? How freely does it move, do you feel any binding without the belts, do they bind in the exact same place. This kind of problem if very hard to do from my end. electronics re easy, but I can’t physically touch your machine to know if it is too tight so I can only suggest to loosen all the tension bolts and only tighten them later if you find you are getting chatter or something. This whole thing should be much looser than most expect.