Hi, Worked on a # of Onix CD's and they all use the same basic lazor transport by Philips. I found that the spindle motor or cd motor assy is the culprit. The plastic housing/platter the cd sits on get pussed down and the lazor can't focus properly any more. This is in lew of that you just repaced the lazor it self and not the whole assembly which would include lazor, and spindle motor.
If you just replaced the lazor it's a easy fix. Pm me for more info if needed.
Gary