I have a recurring problem with my Plextor PX-716sa. Basically, it can't detect about 1 in every 5 audio CDs I put in the draw. When it does detect the CD everything seems to work fine (can get track lists from FreeDB, play CDs and extract perectly etc.).
To illustrate the point, I have a brand new 3 CD box set. Out of this, CDs 1 and 3 are not detected, but CD2 is fine. All CDs are from the same box set (so am thinking it's not some dodgy copy-protection), and all brand new (so it should not be associated with the quality of the CD). And the behaviour is the same for a particular disk - if it can't detect it, then it never can, after re-starts etc. If it can detect it, then it always works.
When it can't detect a CD, I get a blinking amber LED (blinks twice, goes off for a few seconds then twice again). From the Plextor site this seems to indicate that the laser can't focus. Not sure what this means. Anyway, I have mailed Plextor (but I won't hold my breath based on previous experience), just wondering if anyone else has had a similar issue, or can help pinpoint the problem.