Neo Geo CD top loader lens replacement

Laguy

n00b
Joined
Mar 1, 2014
Posts
14
Hi,
I'm trying to replace the lens inside my NGCD top loader model.
I'm almost ready to swap the lens but I can't do it because a gear obstruct the old lens exit.
Is there any way to remove the top gear you see in the pic below?

ztaf2qAl.jpg
 

Laguy

n00b
Joined
Mar 1, 2014
Posts
14
Never mind, I did it.
There was a small circlet that hold the gear in place.

I replaced the lens but my NGCD still didn't read the CD.
Turns out the spin motor is probably the culprit.
I push down the close/open switch and the CD won't spin.
To be more precise the motor try two time to spin counterclockwise for half a second and one time clockwise (again for half a second) and then stop completely.

How hard is to replace the spin motor?
What model should I buy?
 

DarkRider

n00b
Joined
Jul 19, 2014
Posts
43
There is a small plastic washer on the top of that gear. You need to remove that washer and the gear will come off. Be care though when removing it! When I replaced a lens that washer flew off and lucky for me it landed on my hand. If it flies somewhere you might not be able to find it again.
 

Laguy

n00b
Joined
Mar 1, 2014
Posts
14
Does the disc not spin at all?
As for a full 360° spin no.
It move the CD like 45° and then stop.
The action sequence is as I described above:
"To be more precise the motor try two time to spin counterclockwise for half a second and one time clockwise (again for half a second) and then stop completely."

What model is the NGCD top loader motor? is it hard to replace?
 

DarkRider

n00b
Joined
Jul 19, 2014
Posts
43
Where did you get the lens from? I'm assuming it's brand new? I've had the same issue with a top loader not spinning and it was the lens. I had a lens I bought die after about 3 months so i got one from a different seller. You can try adjusting the pot on the back of the lens slightly to see it that will get it to spin but it's hard to get it just right to read the disc. Also I'm assuming the piece of plastic that hangs down on the cd door is still there and pressing down on the button inside the lid?
 

Laguy

n00b
Joined
Mar 1, 2014
Posts
14
Where did you get the lens from? I'm assuming it's brand new? I've had the same issue with a top loader not spinning and it was the lens. I had a lens I bought die after about 3 months so i got one from a different seller. You can try adjusting the pot on the back of the lens slightly to see it that will get it to spin but it's hard to get it just right to read the disc. Also I'm assuming the piece of plastic that hangs down on the cd door is still there and pressing down on the button inside the lid?
I got the lens replacement from Hong Kong (should be brand new).
The piece of plastic is there and when I did the test I used a piece of scotch to hold down the switch inside the console.

So you think it's the lens and not the motor?
 

DarkRider

n00b
Joined
Jul 19, 2014
Posts
43
I just think the lens is what causes a lot of the problems with the disc not spinning. It was almost like the lens didn't recognize that there was a disc in the system. With the lens that went bad after 3 months for me, I was able to adjust the pot and get it to spin, it just wouldn't read the disc. I also unintentionally shorted the motor and was able to see it spinning fine. :P Now someone can correct me if I'm wrong that's probably not good for the motor, but if you really want to check it you can try applying power to the contacts for the motor to see if it will spin at all. I ended up getting a lens off of ebay from a guy in Florida that started working right away.
 

s8n187

Quiz Detective
Joined
Mar 20, 2014
Posts
89
hi Laguy , i got about 12 Lasers for my 2 CDZ's and about 30% of them do not work or failed in one hour of a break in stress test. So yeah your Laser could be DOA , if you do get another one/replacement put a game in and let it run for 2 hours straight times 5 sessions.
 

Laguy

n00b
Joined
Mar 1, 2014
Posts
14
@DarkRider @s8n187
When the lens failed the symptoms were the same as mine?
That is the CD start spin counterclockwise for two time (about 45°) then one time clockwise (again about 45°)?
The laser seem to detect if there is the CD or not in my case...
 

DarkRider

n00b
Joined
Jul 19, 2014
Posts
43
I don't know about it doing it 3 times, but yes, it would spin slightly in the drive when I closed the lid. It was only about a 1/4 turn to a half turn that it would move.
 

s8n187

Quiz Detective
Joined
Mar 20, 2014
Posts
89
yes the behavior of my DOA Lasers is similar to yours........................me personally i have given up on Neo CDs and switched to MVS
 

DNSDies

I LOVE HILLARY CLINTON!
Joined
Mar 15, 2015
Posts
1,983
Sometimes when replacing CD units, the stock ones bought from China or Hong Kong will not be configured correctly, either due to age or rough handling during shipping.

I know this can happen with, say, the Mega CD. Not 100% sure if this also applies to the Neo CD.

If someone on here has a copy of the Neo Geo CD Maintenance Manual, it would say for sure.
Usually, configuring a new laser for your CD based unit requires an oscilloscope so you can measure the frequency of certain test points and adjust the potentiometers on the unit until it matches the wave shape shown in the manual.

From what I remember though, the NGCD only has a laser power adjustment pot.

You could try taking a picture of its position, marking a notch on it, and turning it VERY VERY slightly (like, 1/32nd of a turn) and see if that helps make it read discs.

I'm not too familiar with the NGCD, so this is mostly based on my experience with Mega CD and TG16 CD lasers.
 
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