[JayLam]

Here is my first thread in this forum.
I got a second hand LINN Unidisk 2.1 in great condition last month.
 
But last few days i found the player couldn’t read some CD, and im sure the CD are new and without any blemish purchased from Japan. Most of my CD can be played immediately even some of them are with lots scratch , so i think the laser in the player is in great working condition , but why some CD can't be played , it's weird . I have no idea what‘s wrong with the player.
Is the CDs problem ? I don't think so , cause they can be played on my LINN GENKI before.
Is the laser broken? I don't think so , most of the CD can be played in smooth.
 
Here i need help to settle this problem down,any explanation or suggestion will be appreciate.Thanks.

 

[NA Blur]

It could be the layering of the CD, it could be the encoder, it could be a dirty lens.
 
Try some CD drive cleaner or if you can find the laser lens use a drop of rubbing alcohol on a lens tissue or eyeglasses cleaning tissue ( silk typically ) and gently wipe the lens.  Inspect the lens using an magnifying glass or with a flashlight and see if there is any residue or debris left over.  Repeat until the lens is clean and try again.
 
There may be some potentiometers in there that control the current to the laser.  You can gently turn those up or down until the problem is fixed.  Try 1/8th turns at first and then go to 1/4 turns.  If you turn the potentiometers more than 2 full turns and no result the laser may be shot.  Also check the alignment of the laser and make sure it is not lasing off at an angle.
 
My money is on a weak laser and I would just turn the pot(s) a bit.