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Thread: Neo Geo AES not booting, black screen, repair in progress

  1. #1
    . Bratwurst's Avatar
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    Neo Geo AES not booting, black screen, repair in progress

    Serial #020213, sticker underside says use Pro Pow only.

    Pic of the board: https://i.imgur.com/IWA8dvA.jpg

    System was given to a friend as-is years ago, and they have given it to me in an attempt to fix it. I presume it was fed the wrong power supply at some point. I'm hoping to get it working to give to another friend.

    Hooking up composite cable to Samsung LCD and a Sony 8" PVM, both black screen on power up with no game. Power supplied from bench top variable supply dialed to 5 volt but it never pulls more than 1.15-1.2 amps. Q2 PNP transistor B1135 positioned right after the switch is reading ok via diode checker. Voltage reading 4.75 volt immediately after D1 zener diode...

    Don't have a game on hand to test with, but will get one soon. I figured even without a game I'd get a color screen like blue, etc.

    Didn't see any damaged traces but I will give it a harder look again.

    Ran console with power for two minutes, measuring temperature with IR thermometer on all ICs. LS86 & LS05 next to the bios chip were getting warm up to 89F while everything else stayed 70F-72F (just a few degrees above room temperature.)

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    . Bratwurst's Avatar
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    A game came in the mail, Samurai Spirits, still the same symptoms. Pulls 1.3 amps now instead of 1.15. Black screen, there is an audible buzz through the audio line on the PVM but not on the LCD. This buzz is present with or without the game btw.

    Planning on removing the bios to put in a socket and install the diagnostic rom, any recommendations?

  3. #3
    SHOCKbox Developer
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    What is the voltage coming in at pin 1 of the bios? Pin 2 is GRND.
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    Last edited by BIG BEAR; 03-14-2019 at 12:47 AM.
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    Getting 0.424 volts.

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    You need to be getting a reading of 5V there. Changing out the bios in favor of a diagnostic will do you no good until you have 5V hitting every component that requires it.
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    Quote Originally Posted by Bratwurst View Post
    Getting 0.424 volts.
    In case of 'PM BOX FULL ANXIETY' , E-MAIL ME

    bigbearatdreamamusement.net replace "at" with an "@"

    I'd like to sincerely THANK everybody that supported SHOCKbox over the (EST 2001) 8 - 9 years I did it.
    is stocking the SHOCKbox right now!! They also have a huge library of SHOCKbox inserts for DL and or printing.
    LE GEEK SHOCKbox inserts

    I'm not protecting myself from you....I'M PROTECTING YOU FROM ME.
    SKYWAY PRO Keep this a secret!

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    It was early enough I might have read the initial reading wrong- or touching solder to the vias has rectified something, because I'm now getting 5 volt on the bios. Double checked that for sure. Symptoms are unfortunately still the same.

    I measured the frequency of color burst clock and the bodge board output and they're both correct, 3.579Mhz and 24.167Mhz respectively.

    EDIT: I think it's the CXA1145, I'll post more later.
    Last edited by Bratwurst; 03-16-2019 at 01:13 PM.

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