Results 1 to 6 of 6

Thread: MVS Sound/Power Issue

  1. #1
    . doaal's Avatar
    Join Date
    May 2018
    Location
    Canada

    Posts
    4

    MVS Sound/Power Issue

    Hi all,

    Recently I bought my first MVS board (MV1ACH) on the cheap. The owner tried to do a stereo mod and had the watchdog colour issue--swapping the stock BIOS to UniBIOS fixed this. Hey, a working Neo! Since he cut the 12v trace I assumed all I had to do was reattach it and I'd have sound, except when I did, the board wouldn't power on. I get a small flicker from my power supply and then it shuts down.

    I removed the copper wire I used to connect the trace and the Neo board powers on again as normal. I'm assuming some of the other work the past owner did on the board is causing some kind of issue with the 12v? I've included a picture of the part of the board where the work has been done, along with the cut 12v trace. Aside from what's in these pictures, he installed a battery holder but that's pretty idiotproof.

    Any help with this is appreciated.unnamed.jpgcapture.jpg

  2. #2
    Geese's Thug
    ack's Avatar
    Join Date
    Apr 2009
    Location
    Seattle, WA

    Posts
    275
    That red wire in your first picture is connecting 5V to 12V rail. I assume the guy was trying to do the 5V audio mod which is to power the audio amp off the 5V rail instead of the 12V one. By reconnecting the 12V rail you are causing a bridge between the 2 voltages, which is bad.

  3. #3
    . doaal's Avatar
    Join Date
    May 2018
    Location
    Canada

    Posts
    4
    One thing I did try after taking the picture was removing the wire. Definitely safer, but didn't fix the issue.

    Tomorrow I'm grabbing some sandpaper and desolder braid so I can try making a very clean retrace, just to be on the safe side.

  4. #4

    Neo Alec's Avatar
    Join Date
    Dec 2000
    Location
    USA

    Posts
    8,345
    Look up the 5v Only Mod instructions on Jamma Nation X and make sure you reverse all the steps that have been done.

  5. #5
    . doaal's Avatar
    Join Date
    May 2018
    Location
    Canada

    Posts
    4
    The only thing I haven't been able to reverse is the cut between the sound amp and 12v. But testing the amp's pads with the rest of the board I seem to be getting continuity. Are there specific resistors/spots I should test as I try to repair the trace?

    I'm not the best with electronics repair so bear with me.

  6. #6
    . doaal's Avatar
    Join Date
    May 2018
    Location
    Canada

    Posts
    4
    I've fixed the problem and she boots! But the only sound I'm getting is the coin insert. This may be a capacitor issue?

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
  •