Sega CDX noise in the picture?

Discussion in 'Sega Discussion' started by Jeppex83, Nov 26, 2012.

  1. Jeppex83

    Jeppex83 Rapidly Rising Member

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    Hello I have got a Sega CDX console. There is some noise in the picture. Is this common issue in CDX? The noise is something like radio waves coming up to down, sometimes left to right or vice versa..

    I don't have original CDX charger. But I have tried 2 different types charger:: the Sima SUP-60 and Asus eee 700. Both should be good chargers for CDX, they are 9.5v Output and they give more than 1.5A.

    I have also tried with two different rgb scart cables, but everything looks the same.
    I think it can be a power issue because when I twist and rotate the power plug when the power is on, it looks like the waves of the noise are changing their pattern and moving a little.


    But I found a solution for this: When I plug in a Sega 32X and play games through it the noise is missing. (almost all noise). There can be a littlle noise in the screen. When you focus to find it, you can found a little.

    But do you know what can cause this problem or is there something that I can do to the system? I would be very happy to fix this problem..



    Thanks guys!
     
  2. Chilly Willy

    Chilly Willy Robust Member

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    I've seen that due to RF noise from flash carts. No flash carts are made to pass FCC certification, so you can expect noise. :D

    The 32X is designed to minimize both the production and reception of RF noise, ESPECIALLY if you use those metal pieces that come with the 32X. Most people have no idea what they are - they're RFI shields.
     
  3. sonicdude10

    sonicdude10 So long AG and thanks for all the fish!

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    I've had radio noise come from PSU before. Might try an official one.

    Also no mention was made about using a flash cart. If that is being used try official games to see if noise persists.
     
  4. Jeppex83

    Jeppex83 Rapidly Rising Member

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    Yes, I use mega everdrive. I ordered now a new power supply and original game that have much noise I have seen. I got sonic games but they don't have grey color and what I noticed grey color is the color which causes the biggest noise to the screen. Could there be a problem in the cart, could the flash card be the problem? Or might there be a problem inside the CDX? Faulty capacitors?

    If I found the original game is working very well then it have to be a flash card that causes problem?
     
  5. Jeppex83

    Jeppex83 Rapidly Rising Member

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    By the way... Is there any way to do shielding to the cartridge? I just can't believe it could be a cartridge shielding problem....
     
  6. TmEE

    TmEE Peppy Member

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    The noise comes in combination of bad ground, too little/worn power supply caps and not so great switch mode power supply that CDX uses.
     
  7. Jeppex83

    Jeppex83 Rapidly Rising Member

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    I am pretty good with soldering iron. But I am not pro with electronic studying... :p Must study more that I can repair this thing.. I have read this is common problem with CDX, its odd that I cant find any solution on internet..
     
  8. Jeppex83

    Jeppex83 Rapidly Rising Member

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    Could this be a ground loop? If it is, how I can fix it? do I check every joints or do I use multimeter... The problem is somehow connected to the power supply, when I twist the power supply, I can clearly see how the waves change their direction on the CRT screen. But can it be then ground loop because the power supply is not grounded one...?

    Are the noise issues always with scrolling interference or can they be static ones. I just want to know where to look, before I break something or start soldering good parts away...

    EDIT: Maybe this is stupid question but can I found bad grounding if I solder off the pin of the scart socket one by one, test the screen, solder it back, try another... and when the scrolling waves goes off then I have found the bad grounding?
     
    Last edited: Dec 5, 2012
  9. Lum

    Lum Officer at Arms

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    If in Europe try a real Multi-Mega power supply first.

    It could be your non-original power supplies, don't like the higher power usage of mega everdrive?
     
  10. Jeppex83

    Jeppex83 Rapidly Rising Member

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    I could try official one but they are so expensive ones because they are so rare. Sima-SUP 60 should work because it is 9.5V, asus eee 700 should work because it is 9.5V and the http://www.retrogamecave.com/sega-ac_adapter.html should work because many user have said it should work. But all of them gives that same issue. Scrolling lines on the picture.

    I try to take a video of this problem.

    But I don't understand why 32x filter the issue. Maybe it is grounding problem... Or there is some issue on the CDX video signal that it don't put enough power to the output. When the output is putted to the 32x it put some extra power to the signal and then it is much better. I don't know :(

    Oh... And the issue happen with original games too.. In cd mode and in cart mode
     
    Last edited: Dec 6, 2012
  11. Ragnarok

    Ragnarok Member

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    On my Multimega I've seen them on RGB depending on what the CD drive is doing. With the Orginal 9.5v 1.3A Power supply too. Doesn't make much sense why there was a difference in spec with the CDX 1.5A one.
     
    Last edited: Dec 6, 2012
  12. Jeppex83

    Jeppex83 Rapidly Rising Member

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    So there is some difference in multimage and cdx amps... Didn't know that... But there shouldn't be any problem if using more amps than 1.5. But there can be some serious problem if using less amps than it is mean to be.I don't believe the problem is the power supply issue. I have tried 3 differen non official power supplies and always the same problem..
     
  13. Jeppex83

    Jeppex83 Rapidly Rising Member

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    OK tried to take the video about the noise.. But it is impossible because crt is blinking 100HZ itself... But I try to explain the noise: It Have many lines next to each other. They are not precisely straight and they are scrolling downwards then they change pattern and suddenly they are scrolling upwards.. There is no exact pattern what they use sometimes they scroll faster sometimes slower. It's like some radio waves scrolling on my screen.
     
  14. Flash

    Flash Dauntless Member

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    CDX works very well with NeoGeo CD PSU. You will need to build a connector adapter but it's way too easy for anyone who knows how to hold a soldering iron. You can even make a simple small europlug-like connector that goes to NGCD PSU out, and connect your СDX through diode bridge, so you won't have to worry about polarity.
     
  15. bart_simpson

    bart_simpson Dauntless Member

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    Ok right the asus psu 9.5v is fine i use them as replacements work fine
    It will be bad caps or ba av socket i have a cdx with bad av socket i had the same fault as this
    I replaced all the caps on the power board and replaced the av socket and now works a charm
     
  16. Ragnarok

    Ragnarok Member

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    that's handy to know Bart. My Multimega might be in need of some TLC with new caps, maybe a new AV port.
     
  17. Jeppex83

    Jeppex83 Rapidly Rising Member

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    What kind of caps you changed? Did the caps like these 0.1uF Caps: http://www.freewebs.com/vgmods/segagenesismodificaitons.htm
    Or did the caps the bigger electrolyte caps?

    And did you remove the av socket completely or just desolder the old one better?

    I am so exiting that maybe this problem can be solved :)

    Thanks!
     
  18. bart_simpson

    bart_simpson Dauntless Member

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    Right the 470uf caps on the power board cdx has lots of small caps.

    As for the av socket i can get hold of them i got a friend that used a hot air rework tool to remove the old jack i have a cdx that needs a new av socket.

    If need be i could take a look at the unit for you.

    As i have part on hand.

    All the best of luck.
     
  19. Jeppex83

    Jeppex83 Rapidly Rising Member

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    Thanks man! I think I am going to open that thing and try to change the caps first. If that don't work to the issue then the av socket is the next thing. I think the removing av socket is pain in the ass. Do you know where to get new sockets? Remove them from the broken CDX units or are the socket same size as the genesis has? It would be cool to find place that sells only the av socket that I dont have to buy the whole unit to the spare parts..

    I found this site:http://console5.com/wiki/Sega_CDX It says the Power PCB has 6 caps.. I think you changed these caps. I will start these too to solve the problem!
     
  20. Lum

    Lum Officer at Arms

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    Better think more careful than that. You do NOT just open a CDX without considerable talent to avoid damage. These things are tightly packed with small parts.
     

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