It has a CDM2 transport driven by TDA 5708 and TDA 5709. I think it is
the famous Philips original control board...
At the end of the drawer closing procedure it sometime reads the TOC
correctly. Sometime not. Same turning it on or pressing play with a CD
in.
When the startup sequence is successfull (TOC content correctly
reported on display) it plays two/three tracks, ...then fails.
When the startup sequence is successfull I can start palying at track
1 or 21 it always works for some time.
When palying some noise comes out the transport: it seems the pickup
is scraping the disk;
When failing sometime (not all the times) the arm swings and badly
beats at enf-of-route.

My conclusions a
drawer motor and gear ok;
laser ok;
focus ok;
tracking ok;
pickup ribbon investigated checked ok;
not ripple found in any of the power lines.
CAPS on the control board all measure "normal" ESR (normal means
"compared with new bees I have");
May be the laser power is low... is there anybody able to describe a
correct procedure to check and tune the laser power?
Emanuele.