CD player distortion on all CDs

I've had a problem with a good CD player's drawer sticking all the time. I thumped it a few times...no help. This week got the drawer problem fixed at a local audio repair shop but now when I play ANY CD, there's a great deal of distortion. Once the CD started out fine then in 20 seconds started distorting. Mostly it starts out distorting. I suspect my thumping the top did the dirty trick. What's likely the cause? Laser misalignment? Is it easy for a small-town audio repair guy to fix, or is it likely a new laser assembly is needed? Thanks for your ideas. BTW, I've hooked up 2 other CD players to that audio system and no problem. And the CDs themselves are fine.