Theta Data Basic cd transport help

Hello All,

  I need some help on my Theta data basic transport. In March I had my data transport recapped by a local audio shop. When I got it back it sounds amazing, great detail. But my problem is now it has problems reading some cds. If the cd has over 12 songs it will read error and not play. So we replaced the cdm9 laser and still the same. It plays some cds perfect and others it just will not play. So the shop said it was that way when that got it from me. Not true I have had this transport for 10 years with no issues just thought it was time to have it recapped and it did make a great improvement in the player. So does anyone out there have any idea what it might be? It worked perfectly  before the recapping. Please let me know if anyone has any ideas what it might be would be great. Thanks
@master838, my Theta Data Basic developed similar behavior (I think it’s a failing common to the model), and I traced the cause not to the gear, but rather to the rubber belt that turned the gear. I found a replacement belt on ebay for a coupla bucks, removed the old belt and put in the new, and all was well.
Hi All,
Thank you so much for your suggestions. I have found out the problem. It a broken gear and have already ordered the parts. 
Again, you guys are awesome.