Results 1 to 15 of 15

Thread: MV-1 Consolizing and Repair Questions Audio / Video

  1. #1
    Timid Neo Newbie

    Join Date
    Oct 2017
    Location
    Pennsylvania

    Posts
    8

    MV-1 Consolizing and Repair Questions Audio / Video

    Hi, I recently bought a MV-1 that plays games but didn't have any audio. This is gonna be a little bit of a book so I apologize for the length. I'll post all the details of my setup at the bottom I got it in plans of adding it to my console collection and setting it up so I can play it without the need for a bulky cab. I've already built my own video encoder board for composite (I know lol). I use a crt for stuff and don't really wanna go rgb quite yet with all my systems. I noticed a problem where it seems I'm not getting any of the R in my RGB signal. This isn't a problem with the video board as I have pulled voltages from the jamma pins for the RGB. The G and B are about in the 100-120mV range but the R is like 8. When I was testing the video early on there seemed to be a normal color image but not much anymore and I'm not quite sure why. The resistors before the jamma pins all check out to their printed values. How far back and where do I check to see where the red signal is getting jacked up?

    The audio issue was only described as there wasn't any, but I noticed the audio switch (stereo / mono) is just plain gone, well half gone. The top is gone and the exposed internal pins are still there. I've been trying to work all the traces around it out to see how to potentially bridge these gaps. But since I'm going the 5v route on this, I may need help figuring out how to set up the headphone output part. I've tried testing the headphone out but not getting any audible signal but there's voltage going to it. I've also probed the YM2610 pins and they are all outputting voltages on all the pins though I'm not fully sure what all of them should be putting out but I have read the datasheet on it.

    The only other issues with it are that I am suffering from some slight graphical issues as well as some some random resetting on a few games I've tried. I saw in another post that it could be from the console drawing more power than the supply can put out on some games. I'm using an adapter I grabbed at goodwill that's 5v at 2.6A which from what I've looked up, should be plenty(?). I've tested a few games and while the system is running, I've pulled about an average draw in the 1.5A range. Maybe there might be some good games to suggest I try that are known to be a little beefier. I did try using a credit card and some Deoxit D5 and using part of an old but clean sock to clean the pins. I might give it another pass, but the initial pass got rid of that NES style glitch look I was originally getting .

    Anyways, those are the initial problems I would greatly appreciate some help on. I'm new to owning a MVS but have a good foundation in electronics knowledge. Hope to hear back


    Set up Details:
    Neo Geo MVS Model MV-1
    Power adapter: +5v @ 2.6A
    Only game to test is 161-1 cart with capacitor audio mod done
    Power, ground, and video done using jamma harness

    Current video I'm getting out of it (don't mind the framerate, it's just my capture)
    https://www.youtube.com/watch?v=dNxr6PuV1AI

    Audio switch pics (the blue wire is 5 volt audio mod I found here http://www.jamma-nation-x.com/jammax/tutorials.html ):
    https://imgur.com/a/5B9yH
    Last edited by TokyoScarab; 10-20-2017 at 04:21 PM. Reason: Added more info

  2. #2
    Timid Neo Newbie

    Join Date
    Oct 2017
    Location
    Pennsylvania

    Posts
    8
    I did find this handy image though for a MV2 (not heard of that). Anyways, I know that board designs usually don't change drastically or key hardware features don't change much because cost lol So this resistor array I am going to assume works exactly the same for this as it does on mine. The 3 colors outputs of the resistors match the values I'm reading from the pins. So I see that each color is connected to a 7 resistor array and some flip flops? It seems like there are certainly values going into each resistor that seem good, but not sure why the red one is cut to practically nothing.

    For the marked RGB spots here are the values pulled on the input and output of the resistors:
    Color: input / output (resistor output matches the jamma pin for each output)
    R: 365mV / 8mV
    G: 408mV / 146mV
    B: 452mV / 117mV

    mv2-rgb.jpg

    http://www.jamma-nation-x.com/jammax...ts/mv2-rgb.jpg (source link for image)
    Last edited by TokyoScarab; 10-21-2017 at 04:06 AM. Reason: Realized I didn't catch something on the board and a couple things weren't how I thought

  3. #3
    Timid Neo Newbie

    Join Date
    Oct 2017
    Location
    Pennsylvania

    Posts
    8
    Ok, I've solved the audio issue, so now all I really am trying to figure out is why the red color signal is isn't really outputting and why some of these games are randomly resetting.

  4. #4

  5. #5
    Timid Neo Newbie

    Join Date
    Oct 2017
    Location
    Pennsylvania

    Posts
    8
    I've already solved the issue today. One of the input pins on my encoder board is apparently dead so it wasn't allowing any current to flow. I had tried a thing where I switched the red input with the green to see what would happen. The red now was actually flowing but the green was now stopped. So everything is pretty much solved. If anyone is having any troubles on a missing color, I did find some good resources you might want to check out:
    https://wiki.neogeodev.org/index.php?title=Color_issues
    http://www.neo-geo.com/forums/showth...video-problems
    https://forums.arcade-museum.com/sho...d.php?t=301176 (this had some good info on the MV-1's audio switch mapping)

    Only problem is the random resetting issues with some games on the multicart. Not sure what it is. I feel having 1A in reserve while operating under load is probably plenty(?). I'll try giving the slot another hit with contact cleaner and something to clean up the grime and see if it works. Also, if you have a MV-1 and a missing switch, unless you're using the audio through the JAMMA, the switch won't matter. It only alters the JAMMA audio output. So if you are using the side speaker or headphone out, you won't need it (info is in the link above).

  6. #6

  7. #7
    Timid Neo Newbie

    Join Date
    Oct 2017
    Location
    Pennsylvania

    Posts
    8
    The AD725. I'm aware of other chips like the Sony CXA series, but was just the first one I had looked into and didn't require too many components.
    Last edited by TokyoScarab; 10-24-2017 at 08:11 PM. Reason: typo

  8. #8
    Timid Neo Newbie

    Join Date
    Oct 2017
    Location
    Pennsylvania

    Posts
    8
    Yea, I've cleaned the cartridge slot again and changed the power supply to one that does keep a constant 5v with games on, but I'm still getting random resetting. It seems to be only in some games and in the same spots usually. All of the KoF games I've tried seem to all reset within either the main menu or shortly thereafter. This still has the original battery. The battery hasn't leaked and apparently still works. I measured it and it's outputting about 2.8v with the system off. The board says that it's supposed to be 3.6v. That could be an issue then.

  9. #9

  10. #10
    .
    Join Date
    Nov 2017
    Location
    Philadelphia

    Posts
    2
    Hey guys but just recently bought a Neo Geo mvs console


    Is this component or regular composite the one side doesn’t even have wires .

    5CA36C55-289D-4A16-BFC3-A275435246AC.jpeg5CA36C55-289D-4A16-BFC3-A275435246AC.jpeg

    8137A29D-27FC-4E21-92C1-9116A8522F80.jpeg8137A29D-27FC-4E21-92C1-9116A8522F80.jpeg

  11. #11
    Timid Neo Newbie

    Join Date
    Oct 2017
    Location
    Pennsylvania

    Posts
    8
    I don't own a logic probe, but I do have a scope and did a small recording of it trying to boot up KoF 94. Before I did the recording and was probing the pin, I noticed that the longer that I let the resetting go, the farther it would make it before it would reset. It usually doesn't make it to the title screen or the spinning letter, but near the end of about 5 or 10 minutes, it was making past the spinning letter to the fighters and then resetting. Could be a helpful clue. I did power cycle the system to do the recording and noticed it was early in the game being loaded that it would reset. In this video, I put the probe on the reset pin partway through the Neo Geo splash screen. Hopefully this can help. It certainly seems like there's something triggering it

    https://drive.google.com/file/d/1rSE...ew?usp=sharing

  12. #12
    Member pnauts's Avatar
    Join Date
    Jun 2017
    Location
    France

    Posts
    36
    Quote Originally Posted by Krec9 View Post
    Hey guys but just recently bought a Neo Geo mvs console


    Is this component or regular composite the one side doesn’t even have wires .
    Composite and S-Video (slighlty better than composite normally)

  13. #13
    NEST Puppet
    joala's Avatar
    Join Date
    Oct 2017
    Location
    over east

    Posts
    173
    Quote Originally Posted by pnauts View Post
    Composite and S-Video (slighlty better than composite normally)
    Yeah thats definitely composhit
    Spice god of Borneo...


  14. #14
    .
    Join Date
    Nov 2017
    Location
    Philadelphia

    Posts
    2
    Thanks guys looking to get it modded to run component anyone know where a good place to get this done?

  15. #15
    Timid Neo Newbie

    Join Date
    Oct 2017
    Location
    Pennsylvania

    Posts
    8
    Ok, so I thought to measure the output of the battery when the system is running. I'm getting like 4.4v which seems high considering the battery is marked on the board for 3.6v. I know the battery mod involves removing a resistor as part of the process so I'm not sure what the normal voltage going through this part of the circuit should be, but this battery is old and should be removed. Can't risk that being an actual issue and having it destroy something

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
  •