What to do when your CD-i player read CD-i discs for < 30 seconds and then stops, giving '---' or 'ERR' on the LCD panel (Retrostuff and Omegalfa discuss the quality of the CDM laser unit)

When the laser of your CD-i player is dying (when it doesn't read any discs anymore) you might want to replace the laser unit. Depending on the CD-i player type, different laser units were used. You can see an overview in this table: http://www.icdia.co.uk/players/comparison.html. An example is pictured above. The CD is placed on the 'spindle' on the left, the laser can move over the 'sledge' which goes here from left to right, being able to read all parts of the CD. In all the repair topics that came by on social media or on other places, the motor of the CD-i player was never the cause when a CD-i player failed to read the discs. It might probably be the optical lens, perhaps an unfocused lens or a turntable that is stuck. CD-i Omegalfa explains: "In all the repairs I have done, the cause was not the motor. [I see] 2 possibilities: Either the turntable is stuck or the lens is unfocused. I do believe all 3 CDM's were ok. When you test the turntable with your fingers, you have more power than the motor. I've got this issue on 3 players. They started reading the disc, and then, ERROR message." 

If you want to replace to optical lens, you'll need to buy the corresponding CDM laser mechanism.  Not all CD-i players have the same CDM version inside. Over at ICDIA, you can find an overview of the different CDM models in the different CD-i players. Here you'll notice that the oldest CD-i models (CD-i 205/00, CD-i 210/00, CD-i 220/00) have the CDM9 inside, later models versions like the CD-i 210/40 and CD-i 220/60 have the CDM 12.4 version and models like CD-i 210/60 and CD-i 220/80 have the CDM12.1 inside. Most newer compact models in the CD-i4xx and 5xx series also have either a 12.1 or 12.4 CDM model. Is there a difference in quality? Omegalfa: "If we compare the same CDM model, I do believe most part of them are made in China, even if you can find some for sale in US or Europe. Visually they are the same (physically). They do fit in the same position. But they are not compatible at all. The tracks are different, the flat-cable is different, even the components are different." 

And in terms of quality? Is one model (9, 12.1, 12.4) better than the others? According to Omegalfa, it is not a question of quality, but of evolution. CD-i member Retrostuff adds: "CDM9 is built like a tank, old but reliable. The problem is to find a replacement part, they are usually >100€. CDM12.1 and 12.4 are newer and cheaper pickups. I like the 12.4 better (when it works), other people like 12.1 better. It's easier to get replacements for 12.1 (VAM1201/1202). All of them are not compatible with each other. However, Mono IV player can theoretically be modified to accept 12.4 too. But as Omegalfa said, even if cheaper, they are not necessarily worse in quality. All of these pickups are also used in pro CD players by Philips (and Marantz) I think."