Weird System 256 issues

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    • Weird System 256 issues

      New

      Got a Sys 256 from China two days ago, and for the life of me, I can't figure this thing out. I'm assuming some kind of damage, but it's wildly inconsistent in how it behaves. Here's what's going on:

      I get seven beeps at startup pretty much every time, then I may or may not get the blue - black - blue sequence, before something either starts loading, or doesn't load at all.

      I get the "START PROGRAM" message once every six tries. The drive spins up, but this is where the excitement usually ends. It's stuck at the dots forever.

      The fan sometimes works, sometimes doesn't. It changes speeds and behaves strangely. This shouldn't have any effect on the boot process, but can't be a good sign.

      It came with Tekken 5 and the dongle. I got it to boot once, but the dips weren't set correctly, so I got the weird rolling image. Went to the test menu before I thought of starting a blind game, just to see if it would load the fight.

      What I've tried so far: Cleaned all the contacts and ports I could. I thought this might be a disc or a drive issue, so I tried it with a Dark Resurrection disc and dongle. After hundreds of tries I got it to boot once, but the image was even more garbled. I thought I had the DIPs figured out. Apparently not. I swapped in a drive from System 246, which is a confirmed working one. I disconnected the fan. I tried Sys 246 games after setting the 246+ jumper. No go.

      I have to power it on and off a dozen times just to get to the dots. I've tried it in a Blast City cab with a Sys 246 IO. I've tried it with a PC PSU I use with my supergun setup. No go there, either. These setups work with everything else, including System 246.

      It's not the drive, it's not power, it's not the discs and dongles ... I'm at a loss. Any help would be appreciated.
    • New

      Morden wrote:

      I thought this might be a disc or a drive issue, so I tried it with a Dark Resurrection disc and dongle.
      Did you replace the drive too? It might be the motherboard, but I'm inclined to think that the problem is the disc.
      * Arcade-projects, the site where you get the most of your arcade games.
      * If you want Drama go to Neo-Geo forum ---Darksoft
    • New

      Morden wrote:

      The fan sometimes works, sometimes doesn't. It changes speeds and behaves strangely. This shouldn't have any effect on the boot process, but can't be a good sign.
      This is very suspect behavior. I believe the fan runs on +12vdc, which is also used by the DVD drive. If I was diagnosing this I would connect multi meter to +12v on the dvd power molex connector and watch the voltage as it boots.
    • New

      After cleaning the Tekken 5 dongle contacts, I also tried other games with different dongles, all confirmed working. Behavior is always the same. No matter which drive, game, dongle, fan plugged in or unplugged, supergun or inside of the Blast City,

      What is the correct jumper configuration for use with the IO and 31kHz low res image over JAMMA, by the way? Just curious, because there's some jumper config weirdness as well.

      This is very suspect behavior. I believe the fan runs on +12vdc, which is also used by the DVD drive. If I was diagnosing this I would connect multi meter to +12v on the dvd power molex connector and watch the voltage as it boots.

      I'll try that tomorrow. Man ... There's nothing more frustrating than stuff that's dead on arrival. I got a Model 2 as well. I don't have the harness to test it at the moment, so fingers crossed.
    • New

      This is the info I went by. For JAMMA, I set the jumpers to OFF, ON, ON, OFF. The voltages seem to check out. I took it completely apart, gave it a good clean and will test it again this evening. If it fails to boot, I'll have to keep it for "parts". If something has failed on the boards itself, it's probably beyond my skills to repair it. It's a bit too modern.

      Looks like I bought myself a Tekken 5 disc and dongle and maybe a working sub-board, network board and a drive.
    • New

      Hmm ... I guess I *could* turn the voltages up, but the way I ususally test things is with a PC power supply, which has enough juice to power any and all boards I've ever had. I have a hard time believing a stock PSU in a Sys 256 cab outputs 5.7V, but what do I have to lose? Haha.

      Oh, and I do own a Sys 246, and it works just fine, both with my cab and the PC PSU, so yeah. Theoretically, it should work with Sys 256 as well, since it's basically the same hardware.