I'm not sure how old yours is, but I'm guessing since it has a disc player it's pretty new. I have a different brand player, produced in the last ten years, that slows down often. To adjust the timing on it there is tiny mechanical part on the inside that you can insert a jewelers flat head into and lightly turn to adjust the timing. I usually pull up a song on YouTube and use it to compare to the record. However if you adjust it while a records on you risk scratching.
Mine slowed down so often I drilled holes in the bottom to access it without tearing the player apart everytime just to adjust it. After all I can't listen to The Bee Gees slowed down
-Liz
Here's an image of the part, I have three, one for each speed.
[image|999228]