Results 1 to 7 of 7

Thread: Neo Geo CD Repair problems (Laser Unit)

  1. #1
    NEST Puppet
    RyuX's Avatar
    Join Date
    Sep 2018
    Location
    Austria

    Posts
    179

    icon16.gif Neo Geo CD Repair problems (Laser Unit)

    Hey guys

    So I started the repair of my Neo Geo CD recently

    121151238_10225244404605565_3809615623355606284_o.jpg
    Had to replace the Inductor U4 and was happy that it suddenly had a picture but then it kinda had troubles reading discs.

    So I tried to mess around with the pots and calibrated the original laser quite well to the point were I was super happy with the loading times.
    But then it suddenly stopped working so I had to remove the original laser as it seemed the diode hat burned out
    121205317_10225292866897092_4008600634205071207_o.jpg
    (Thats the original one)

    Capture.JPG
    (thats the one I got as a replacement from ebay)

    I got a replacement from Ebay that seemed a little different but it was the same that GadgetUK got in his Neo Geo CD Video so I thought it might work just fine.

    121244808_10225292867257101_8297775415895737196_o.jpg

    After some tests I still have trouble reading the discs - often I get I/O Error 0002 while loading or the disc will not load at all. I tried to optimize the pot settings but the laser seems weaker overall compared to the original one

    121267550_10225292867937118_709981274964211952_o.jpg
    121705799_10225292867577109_2481665337651992427_o.jpg

    Also it is louder and overall I think just a cheap copy of the Sharp original part.
    As of now I can only play some games but I think it also might come down to my power supply (I use a very cheap one 12V/5V that creates quite a bit of switching noise).
    As I think the CD Logic Board doesn't really like noise I ordered another one and hope for the best.

    I will also replace the FFC Cable and ordered some spare parts for the logic board (BA6396FP and CXA1372AQ) just to have them ready in case.
    I already replaced the caps on the logic board but this didn't really improve the situation at all.
    I really want to get this one working because it otherwise is in perfect condition

    120998487_10225251678987420_1272302723475523052_o.jpg

    Maybe someone has some more ideas. Thanks
    Last edited by RyuX; 10-15-2020 at 05:05 PM.

  2. #2
    NEST Puppet
    RyuX's Avatar
    Join Date
    Sep 2018
    Location
    Austria

    Posts
    179
    OK Short update.. At the moment my only real problem seems to be the detection or reading of CDs upon powering the console up.
    When powering it ON I will always land on the TRACK 00 Audio CD Player Screen without any Tracks displayed.

    To fix this I simply have to open the tray once and close it again.. then it will show please wait and then I can press Start to play the game and no more problems after that.

    121294290_368827397816345_7271637561860401953_n.jpg

    However turning it off and on again brings me to the same dilemma.
    It just doesn't seem to be able to read the disc at the beginning.

    The open/close CD Tray however fixes it every time and the disc will read. It is not related to the tray switch etc. The disc will spin up quite fast upon powering on and then you hear a click (the laser coil probably going back to neutral position after being unable to read the contents).

  3. #3
    NEST Puppet
    RyuX's Avatar
    Join Date
    Sep 2018
    Location
    Austria

    Posts
    179
    So a new problem came up just now.
    The Neo Geo CD will go back to the Audio Track Viewing Screen after the second loading screen which is mostly after the main menu or first "demo cycle" is over.
    Really strange.
    All the Pot settings don't help the issue - I marked the stock settings and went back and forth from stock to oscilloscope optimized settings (which are almost equal to stock) without any luck.
    My main hope is that the situation will be better once I have a 10V/5V Power supply with less noise and an all new flat flex cable.

    Other than that I am currently out of ideas - again maybe also those ebay lasers are just no good. But original sharp lasers are easily 50 bucks and more and who knows if these are new anyways.

  4. #4

    Neo Alec's Avatar
    Join Date
    Dec 2000
    Location
    USA

    Posts
    8,868
    I would try ordering a few more replacement laser assemblies and hope to have better luck. Because of the inconsistent manufacturing quality of these, you never know.
    https://basementbrothers.net/

  5. #5
    NEST Puppet
    RyuX's Avatar
    Join Date
    Sep 2018
    Location
    Austria

    Posts
    179
    yeah it's really weird.. there are so many factors on these repairs especially if you can't trust supposed new replacement parts..

  6. #6
    NEST Puppet
    RyuX's Avatar
    Join Date
    Sep 2018
    Location
    Austria

    Posts
    179
    So.. I replaced the flat flex cable (18 pin / pitch 1.25 - length should be around 13-15cm) with a new one.

    Capture.JPG
    Bought it here: https://www.ebay.de/itm/FFC-A-B-18Pi...53.m2749.l2649

    Still had some problems - had to readjust the pots on the board again.
    I can get games to play now quite flawlessly with one catch.. It will never read the CD on power on.

    122173558_353020522685439_692155756354602579_n.jpg

    When I power on it will spin up the CD try to focus and then give up with a loud click noise.
    After I open up the tray once and close it again it will read the CD without any problems and I can press START to start the Game.

    This is the same 10 out of 10 times.
    Not sure what the startup routine is but at least with this laser it will not work.
    But at least happy that I can have a game running.

    So because I ordered quite a few CXA1372AQ Chips I and mine doesn't seem to be broken - I can hook some of you up if you are interested.. I think shipping within europe in an envelope should not be very expensive.
    Should receive them and the BA6396FP Chips hopefully within the next few weeks - as well as my spare laser.
    I wonder if my original Laser was even broken in the first place - will keep it for testing if I ever get hold of another broken Neo Geo CD or if I ever get around switching the laser unit back.

    Will get a proper power supply probably within the next 2-3 weeks to hopefully get rid of the video noise problem as well as improve the CD reading (maybe).

    This is a short video after closing the tray and pressing start:
    Last edited by RyuX; 10-22-2020 at 12:51 PM.

  7. #7
    NEST Puppet
    RyuX's Avatar
    Join Date
    Sep 2018
    Location
    Austria

    Posts
    179
    Short Update:

    Today I received my new Power Adapter which fixed all of my video noise issues
    https://de.aliexpress.com/item/40001...68044c4djO7LLt

    Capture.JPG

    So I can recommend this adapter - shipping was also quite fast for Aliexpress Standards (10 days).

    As for the other problem of the CD not reading on powerup - it did not change anything.
    But I think I can live with that until I get another Laser Unit to see if this fixes that problem.
    Last edited by RyuX; 10-28-2020 at 07:51 AM.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •