Pioneer cld-99s player plays LD discs perfectly, but refuses CD discs, maybe there is some kind of laser adjustment, please tell me.
The player recognizes what is in it now. CD disk but does not want to play it, spins it and then stops.

Buy a CD player.
Be happy it still spins LDs

Try cleaning the lense with water and a swab. Sometimes it’s just that easy an issue.

If that doesn’t work, could possibly be centering or focus issue but hard to say.

I cleaned the lens as you recommended, but it didn’t help.

I would personally try focus now. If you say it plays LD perfectly with no video distortion or audio drop outs, most likely not a centering issue. Also, I think you did confirm the player was able to read the CD TOC? If so, that is a good sign.

Just make sure to take pictures of all the pot settings prior to trying these adjustments.

Yes, it plays LD discs perfectly without sound loss and with good video image.
I will take a photo of the potentiometer, but where is it located and how will it need to be adjusted?
I played more than ten LD discs, they work perfectly, the sound is also excellent, but more than 5 pieces of CD, not one did not play, although the player identified them all as CD discs

If it plays LDs but not CDs then the first item to look at is spindle motor centering.

How can I do motor spindle centering?
centering needed by height?
On this "swinging" bar there is a flag for adjusting it horizontally, do you need to use it to adjust it?
Or does this require replacing the bushings in the engine?

Are these real (pressed) CDs? If so, what condition are they in?

When this player plays LDs is it playing the Digital Sound on the LD?

These are the basic questions that need to be asked first, before you do a single thing like cleaning the lens.

Yes, this is a real pressed CD, the condition is normal (careful storage and use)
When playing the LD disc, the digital sound is played perfectly.
When playing with maximum rewind speed (forward or backward) LD the picture breaks, but when rewind speed is higher than average and lower, the picture is fine.

Ok, just checking. “Confirming the complaint is real” is the first step of any diagnosis.

How can I fix this problem with reading CDs?

Other than the suggestion of spindle motor centering I have no idea.

If it plays LDs perfectly with Digital Sound…I wouldn’t bother. There’s too much risk that messing around with something will mess up LD functionally which is invaluable. You can get a really good used CD played for €50.

The laser needs to read the data on the disc as close to an 90 degree angle as possible. The arc is much sharper for a CD inner track than a LD meaning a CD has a higher requirement for precision centering. I have not done this on a 3070, same as the 99s, for years so you need to look in the service manual for how to do it. It is not an easy process with these older machines. It involves adjustment screws that will move the mechanical base side to side to get the laser at a 90 degree angle from the center of the spindle motor.

How is the motor spindle centered?

In general, today the LD disk stopped working, it is not even detected, i.e. it does not spin....(: