AMI Tone Arm Keeper Springs are very often broken, most of the time missing the end. Without them, setting down the tone arm can make a slight jerk movement.  Always check and replace these on every restoration. They are found on the right side of the record mechanism, where the tone arm peg rides.

Picture shows proper installation on a AMI Continental 2.

First F through Continental 2 and some of the AMI-BAL machines.

Part Number 39-6540