Couple of things to check:
Good luck
- Make sure your platform and table are perfectly level
- Make sure your anti skate is not set too high- try cueing w/o anti skate as an experiment.
- The rubber pad that the arm sits on will get glazed over time and should be replaced... otherwise you can sand it lightly with 300 grit sand paper - this will keep the arm in place longer before the pad breaks away from the arm in act of cueing down.
- The cueing mechanism itself can be set lower by adjusting the set screw. This will mitigate the tendency of arm drift as there is less time for the arm to drift out of place if its physically closer to the record.
- Check for freedom with the bearings in all planes... this may be difficult to do without experience on what to expect.
Good luck