Hi Sam
Thanks for your answer...

Does reducing VCC to say 3 V make any difference?

At the lowest possible value (~2.9V) the player fails reading the TOC
after initial focus search and it may even go into power off mode
during TOC access. Same if I reduce voltage after spinup during play
and try to jump a track.
Up to 3.2-3.5V (midrange) the behaviour improves significantly,
reaches current state. At max (4.1V) the coil driver chip heats up
noticeably but no significant improvement.

My guess is that it isn't a VCC issue.

I tend to agree to that. But having it set to the proper value should
at least give some peace of mind. For now I will go with 3.3V -
Objections?

I assume you've cleaned the lens and any other optics you can get at?

Top of lens only. To fix the tracking coil there was no need to remove
the lens assy and I opted not to make things worse by disassembling
down to the turning mirror and stuff .

How do you know laser power pot is untouched?

Although it is an open case SMD pot located on the side of the pickup
it is secured with some white laquer.

If I adjust the lens tilt for best performance I have a sharp
eyepattern of almost stable height at ~0.8Vpp and the player skips
occasionally. But if I adjust the lens tilt to provides the strongest
eyepattern (~1Vpp) the scope shows noise in the pattern and a general
change of RF packet height along with the revolution of the disc
(though the disc itself does not wobble) - the player may even fail to
readthe TOC or jump to the first track. What I cannot understand is
why the voltage of the eye pattern is higher on the noisy setting
which produces the worest performance. While OTOH the sharpest
eyepattern and best performance produces a smaller pattern. Shouldn't
best player performace, sharpest eyepattern and highest voltage of the
eyepattern converge on one single setting?

-Rainer