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Thread: Neo Geo MV2F help needed

  1. #1
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    Neo Geo MV2F help needed

    I got a MV2F that used to work great as a consolized system. Haven’t played for a couple years. Now it’s having issues. The only thing I did to it recently is upgrade the Unibios to a new version. Now the system plays but crashes, I get a garbled almost camo pattern color somtimes when booting up. Sometimes games play fine. Sometimes they don’t.

    I did a voltage read and I’m sending 5.1V from an arcade power supply (I tried several supplies) and this voltage drops to 4.2 on the jamma edge when I read it using a meter. Please can someone help me troubleshoot or take a look at my board?

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    If psu has adjustable +5v line make sure you are getting 5.0-5.1v on jamma edge or test points on the board. On some jamma harnesses there is substantial voltage drop you have to compensate for.
    Regards, MtothaJ

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    Quote Originally Posted by MtothaJ View Post
    If psu has adjustable +5v line make sure you are getting 5.0-5.1v on jamma edge or test points on the board. On some jamma harnesses there is substantial voltage drop you have to compensate for.
    usually that happens when the wiring is too thin for what it should carry.

    at 4.2v the MVS shouldnt even boot!

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    Did you clear the backup ram when you upgraded the bios?

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    Interesting I can try a thicker gauge

    Quote Originally Posted by MtothaJ View Post
    If psu has adjustable +5v line make sure you are getting 5.0-5.1v on jamma edge or test points on the board. On some jamma harnesses there is substantial voltage drop you have to compensate for.

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    I think I did, but that could cause this issue?

    Quote Originally Posted by Neo Alec View Post
    Did you clear the backup ram when you upgraded the bios?

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    Quote Originally Posted by duo_r View Post
    I think I did, but that could cause this issue?
    Perhaps not the graphics issues -- that could be a dirty cart.

    You mentioned sometimes games play fine. Bad data left in the backup ram can cause resets and other game abnormalities.

    I agree about the wire gauge advice. It's a good idea to use a thicker gauge wire for the main power leads at least, and check the voltage.

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    You could also be dealing with a bad power cap on the mv2f that is causing a partial short and is pulling the voltage down.

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    Got it which one is the power cap? the one by the jamma edge and is 470uf?


    Quote Originally Posted by ack View Post
    You could also be dealing with a bad power cap on the mv2f that is causing a partial short and is pulling the voltage down.

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    There are a couple 470uf caps near the power rails of the jamma edge. You can do a visual inspection and look for leakage around the base and/or the top being domed. If you see either the capacitor needs to be replaced for sure. Its also possible for a capacitor to be bad but show no visual indication its bad.

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    Redid some wiring, got rid of an old power supply, and with a new 5V power supply the system is working although the meter is reading 4.5-4.6 V on the jamma edge connector. If I hookup an arcade power supply I can get it to 5V, but less when using a stand alone power supply. I have tried 2 brand new 5V power supplies with a amperage rating of 3A. Any ideas?

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    3A seems a bit too low to me! A 1 slot MV1FZ pulls around 1.3A with a cart. I would be aiming for around 5A probably.
    My YouTube channel contains some MVS repairs and stuff:-
    http://www.youtube.com/user/GadgetUK164

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    Had similar issues some years ago with my 4slot

    You really need an good PSU, mine is an regular atx PC with 7amps available on the +5v line, and this is where you need to look at.

    Also I had to bridge all four + 5v wires of the PSU together to get the max amps available, just one or two wasn't giving enough juice to the 4slot, the symptoms where the same your are experiencing

    Cheers
    Last edited by dragonpt; 06-24-2019 at 05:29 AM.
    Hyper Neo Geo 64 / Neo Geo CD - Top Loader / Neo Geo Poket Color/ Neo MVS - MV1FZ / 1B / 4F

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    Ian there a good PS out there that isn’t huge and easier to travel with?

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