Sony CDP-M11 and optical laser KSS-240A replacement and adjustment

Hi,

I'm restoring and old CD player Sony CDP-M11 for my brother in law.
The first problem was that after 1 min 30 sec, the reading was in default, and run directly to the end of the disc.

First I've cleaned the optical laser with the Isopropanol, but without success.

Then I decided to change the KS-240A.

The replacing was easy and without any problems.

Then I've tested the reading with an new and Original CD.
First, the optic control the disc and recognize it, it notify that they are 16 tracks on the CD.
I launch the playing, and read the disc correctly, but, only on the five first tracks, when it comes ont the 6th, it stop and say that they are no disc into the reader.
I've tryed with another one disc, with 10 tracks, long player songs (5 to 7 min each). And it does the same things, it read only the first four tracks, but stop at the fifth track

How may I to adjust the optical lens for having a complete reading of the disc?

For information, I've no knowledge in electronical and have no scope.

Sorry for my approximative english.

Thanks for your help and advices.
 
Hi. From the distant, I'd say laser pickup is not the problem. The problem is something about the movement of the laser pickup from innard to the out of the disc. I think there is something that dificults the movement of the laser pickup to the exterior part of the disc. Maybe is anything bad with me motor or the mechanism which moves the laser pickup.
 
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Right. On old player's often the steel bearings need some grease, I use the special high temperature grease for water tap, perfect stuff. Otherwise use vaseline. Or and on gears, some silicone spray. Try.
But be careful, not to get any oil spray on the laser lens! This would stop it working.
 
Hi,
I've controlled if there were nothing to disturb the mechanism, no wires, nothing special to block the course of the lens.
I've put some vaseline on the guides and silicone spray on gear and gears.
I've tested again and it's always the same problem, it read track 1 to 5 and when the track 6 on 16 start, it stop et say "No disc".
I've manually tested the course of the mechanism and it run correctly from the begin to the end of its course.
 
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I've tested again and it's always the same problem, it read track 1 to 5 and when the track 6 on 16 start, it stop et say "No disc".

Solder a couple of thin wires to the sled motor (or measure directly if you can reliably access the correct points) and monitor the voltage across the motor as it plays. If the voltage starts suddenly rising at the point where it fails then the sled is sticking.

How may I to adjust the optical lens for having a complete reading of the disc?

For information, I've no knowledge in electronical and have no scope.

Without a scope it is all guesswork I'm afraid:
https://www.diyaudio.com/community/threads/sony-cdp790-and-kss240-restoration-project.226288/
 
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Moly, You make me afraid, I've no scope ! 😢

Today, I've disassembled the module completely, cleaning it again, lubricate the parts of the disk drawer, and for being sure to have a clean lens, If clean it with isopropyl alcool. I've put back in place the wire, all reassembled and tested.
Result, more bad then before, when I put a disk into, directly it announced "no disc".
Before these manipulations, it worked on the 5th first track, and now it don"t recognize the disk.
I think I've made something wrong!!🥵🥴
 
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It does sound like you have done something. Make sure the lens goes through its focus search routine moving up and down ~3 times when you close the drawer with no disc in the tray. Also make sure the pickup is in the correct position at the correct end of the sled. If you move the pickup manually to the centre of the sled (with the power off) then it should automatically return to the correct position when you power up and open and close the tray.

Just carefully recheck all you did.
 
Thanks Mooly,
Then, I've newly all disassembled, controlled all the mechanism, tested manually the course of the lens, verify all wires,
I've all reassembled and verify again, if all was in order, for me all was clean and correct.
Then, If put it on, opened the drawer, then I've put it off and on again.
I've put a CD into and launch the reading.
Result, all is correct, it read all tracks from the begin to the end.

Conclusion, it's repaired.:happy1:

Thanks to all for your help.:worship:
 
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I've read the CD is working, glad to hear it.
In cases like this, it is useful to see the signals in an oscilloscope of the Sled Motor and Tracking Coils, to see if something is impeding the Laser pickup sled movement. IC102 LA6532M and around circuits, dry joints, etc... could be suspects too.