Check to make sure that the stylus and cantilever are OK. That means make sure that the stylus is still there and the cantilever not bent or tweaked. Put a non valuable record on the platter. Set the arm parallel to the record, measured or by sight. That will get you very close to ideal. You want the stylus center line, mount to tip, to be right at 90-92 degrees to the plane of the record. Most cartridges will be very close with the arm parallel to the record. Tighten all set screws firmly.
Cheers,
Geary