You can do all of the maintenance yourself, including replacing the belt. It is very easy to do. If the belt was not replaced when it was tuned up, then the technician may have felt it was not needed. The technician should have also oiled and greased the motor. By all means, if you do not have a manual, follow Barb's advice and download a manual. That is the best part of owning a vintage sewing machine, you can do the maintenance yourself.