When you are sure you have the gears meshed just right, try punch marking two adjacent teeth on one gear and the one tooth on the other gear that goes between the first two, and you'll never have the problem again. ;c)
Just wish figuring out the 750 was that basic and simple. Hahahahaha
Are you using it on Auto? Even on auto you should be getting stellar images if your glass is up to the task of being able to resolve enough for the sensor.