Neo Geo CDZ disc problem

Demiurgo

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Cool, glad to hear you've got your CDZ up and running again! :)

My joy lasted just for a while... after some time of usage, loading was slower, then stopped. Now laser is not working. The symptoms are the same as before, disc spins for a second then stops. Now the lens has no scratches, and it worked for a while. Maybe something blew up in the laser? Any idea about what to check? :blow_top:

Just out of interest, where did you get your replacement lens from? Generic from eBay? I'd love to be able to find stock of the original Sharp lasers...
I got a generic one from eBay, about 15 euro. Maybe the quality is too low, and I wonder too if a original Sharp part can be found.
 

Tarma

Old Man
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Oh. Sorry to hear of your new troubles... Off the top of my head the only advice I can offer is - check the wires to the data and power leads that plug into the CD laser assy (if these have come loose then you'll get issues). Try adjusting the pot settings ever so slightly - with a screw driver, just make slight turns and see if it makes a difference.

There is the possibility your laser is defective, but you'd need another to compare to confirm.

I've looked everywhere for a nos Sharp assy and can't find one, only these generic Chinese lasers I wouldn't trust as far as I could throw them.
 

Tw3ek

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My joy lasted just for a while... after some time of usage, loading was slower, then stopped. Now laser is not working. The symptoms are the same as before, disc spins for a second then stops. Now the lens has no scratches, and it worked for a while. Maybe something blew up in the laser? Any idea about what to check? :blow_top:

This almost seems like the spindle is stuck too low and causing the disc to scratch the top of the laser. If you place the disc in the unit and try to spin it with your hand, does it make contact with the laser or the bottom of the tray at all?
 

GadgetUK

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Could be the spindle height as a few people have mentioned, but what also sometimes happens is the laser voltage on the new laser is set to some crazy high level and if its a second hand unit it wont last long like that - although I expect that's unlikely.
 

Tarma

Old Man
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This almost seems like the spindle is stuck too low and causing the disc to scratch the top of the laser. If you place the disc in the unit and try to spin it with your hand, does it make contact with the laser or the bottom of the tray at all?

That's a good call.

Also, make sure the three "clips" that are attached to the spindle are holding the CD securely - if they're damaged in any way the CD won't spin properly. Replacement spindles will be near impossible to find other than with junk CDZ units.
 

Demiurgo

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Oh. Sorry to hear of your new troubles... Off the top of my head the only advice I can offer is - check the wires to the data and power leads that plug into the CD laser assy (if these have come loose then you'll get issues). Try adjusting the pot settings ever so slightly - with a screw driver, just make slight turns and see if it makes a difference.

Thanks for the advices. I double checked all the leads, and they are firmly in place. Next thing I will try is turn slightly the pot...


There is the possibility your laser is defective, but you'd need another to compare to confirm.

Problem is it worked for a while... maybe it was so poor quality made and reached the end of his life in those minutes. Bigger problem will be if the console is frying the laser, but the previous one had the obvious problem of scratched lens.


I've looked everywhere for a nos Sharp assy and can't find one, only these generic Chinese lasers I wouldn't trust as far as I could throw them.

I saw one, but it has no Sharp logo or sticker, and the seller says the final product is not the one shown on pictures, so I was doubtful about buying from him.
 

Demiurgo

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This almost seems like the spindle is stuck too low and causing the disc to scratch the top of the laser. If you place the disc in the unit and try to spin it with your hand, does it make contact with the laser or the bottom of the tray at all?

No contact at all. I have the upper case of the console removed and I can see the disc makes no contact with anything. I will check the lens with the camera, but the scratches in the original one look like they were not made by contact with a disc.
 

Demiurgo

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Could be the spindle height as a few people have mentioned, but what also sometimes happens is the laser voltage on the new laser is set to some crazy high level and if its a second hand unit it wont last long like that - although I expect that's unlikely.

It was not a second hand or used laser, but a new one. Chinese made, I must add. Voltage can be adjusted somehow? How can I check it?
 

Demiurgo

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That's a good call.

Also, make sure the three "clips" that are attached to the spindle are holding the CD securely - if they're damaged in any way the CD won't spin properly. Replacement spindles will be near impossible to find other than with junk CDZ units.

Checked. All the three clips, tabs or whenever the name is for those three things in the spindle work correctly: they go up after pressing at the blue center, and down when you put there a disc. :crying:
 

Tw3ek

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No contact at all. I have the upper case of the console removed and I can see the disc makes no contact with anything. I will check the lens with the camera, but the scratches in the original one look like they were not made by contact with a disc.

Did you desolder the point on the laser mech that is bridged to avoid transport damage?
 

GadgetUK

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It was not a second hand or used laser, but a new one. Chinese made, I must add. Voltage can be adjusted somehow? How can I check it?

The potentionmeter (variable resistor) on the optical pickup unit (the laser unit you swapped). That is where you set the voltage - if its higher than it should be it can burn the laser out pretty quick.
 

Demiurgo

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The potentionmeter (variable resistor) on the optical pickup unit (the laser unit you swapped). That is where you set the voltage - if its higher than it should be it can burn the laser out pretty quick.

Here is a picture of both laser, left the old Sharp and right the new one, already installed. You mean the pots I marked in the picture? Do you know which side must I turn to, for example, reduce voltage?

Clipboard.jpg
 

Tw3ek

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Here is a picture of both laser, left the old Sharp and right the new one, already installed. You mean the pots I marked in the picture? Do you know which side must I turn to, for example, reduce voltage?

View attachment 46932

Yes, this is what you must turn to calibrate the laser correctly
 

GadgetUK

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Looks like they are set quite different there! If it doesnt work after setting the new laser to approx the same position the old laser was (originally), then I would say the laser has failed (again). Best way to set these is to measure the RF level on a scope, and I am guessing from the era of the drive the RF level should be between 800mV to 1.2v ish, the lower the better.
 

Tarma

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What happened in the end? Did you get a successful resolution? Sorry I couldn't offer any further advice, but hope you've got it fixed!
 

Demiurgo

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Thanks for asking, Tarma. After getting a second laser from the supplier, looks like everything works fine! :tickled:
 
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