"John Smith" wrote in message
u...
Time to sound uninformed. Is there a solution such as an internal
adjustement on positioning of the laser (I assume stepper motor driven)
that
can be made? Could the lense shape or filter material/colour be a factor?
Could the spin axis be off centred (i.e. should I machine another CD
holding/centering insert)?

The last thing you want to do is fiddle with alignment. You'd never get it
adjusted back. The plastic centering wheel isn't a part that commonly
fails.

Dirty lenses, OTOH, cause all sorts of weird probs.
Clean the lens (gently!) with a swab (preferably lintless foam) and rubbing
alcohol (91% is good). Cleaner discs are worthless for all but the thinnest
films of dust.