Two potential sources of the problem. 1. the laser needs to be cleaned. Try spraying it with compresssed air. That works for my players. 2. some part of the transport mechanism, e.g., the rails, is(are) worn, defective, or just needs to be lubricated. I have an old meridian 506 that I had to send back to the distributor to be repaired.
Try cleaning the laser first. If that doesnt work, likely it needs servicing.
Try cleaning the laser first. If that doesnt work, likely it needs servicing.