There is the possibility that the spindle motor, the motor that spins the DVD is spinning too slowly.This can be remedied by removing the motor from the circuit and applying small amounts of lubricant into any holes in the motor and breifly applying a voltage, no more than 12V to the wires in both directions.Reinstall the motor and try a DVD.If the motor still is too slow, you may have to change it.Beyond this you would need a new player.
Gordon Elder
April 2007