CD player says "No CD"

[Corazones]

I have one of the older type of CD players in a mini Hi-Fi which won't play CD copies. However I find it also refuses to play certain original CDs - not just the newest ones which are copy-protected, but many others. Sometimes just one of a two-CD set brings up the message "No CD", and it's always the same one.
What criteria is it looking for in order to determine what constitures a playable CD? What mechanism does it use to search - mechanical, laser-related or electronic? Is there anything that can be done to overcome the problem or to over-ride the rejection?
Alec

 

[2scoops0406]

The laser is probably buggered, 'fraid a chuck and replace job.

 

[simon26r]

same here. some cd-r disc's will kill your lazer.
sorry..

 

[Igorian]

I agree with the others, but you could try gently cleaning the laser (if accessible) with a lint free bud dampened with some IPA. I've revived a few this way, especially in smoking households.

 

[chilluk]

Or if it's 1 out of a 2 disc set that won't play compare the state of the CD's themselves - for dirt or more importantly scratches - it's quite easy to render them useless. You can get a CD resurfaced if you need to (I have had to resort to this with Cd-Roms of original programs - cost might make music CD's not worth it - although I am sure I have seen some DIY kits)

But if the CD is part of a mini hifi then it's most likely the laser is dirty. Was once told by a repair man that CD players that are part of an overall unit get more call outs because more dust get's into them than seperate units.

This he said was because the vents etc in the unit are to keep the power supply and amp cool - and that on a seperate CD unit there are hardly any vents because there isn't too much heat generated - therefore much less dust and dirt gets in.