Results 1 to 5 of 5

Thread: MVS-4 right audio channel crackle

  1. #1
    . uncivil_enginee's Avatar
    Join Date
    Oct 2016
    Location
    SoCal

    Posts
    13

    MVS-4 right audio channel crackle

    Well ive been working my way through my 4 slot getting things up and running again, and ive come up against an audio issue...

    When I got the game, you had to turn up the volume all the way to hear the games, and the right speaker was disconnected. I hooked it back up, and discovered it had a nice crackle in it a certain frequencies. Unfortunately, one of those frequencies is not the sine wave in the hardware test. It sound fine.

    So I recapped the board, and this fixed the audio volume problem. Now I just have the crackle left to deal with. The problem is in the right channel only. I don't know if it also is present in the head phones (my head phone/card reader board is missing). The problem appears to be independent of the carriages (it occurs in all games, in any slot).

    So now Im really wishing I had a good schematic of the sound section of the board (its an MVH MV4 Board). My best guess at this point is the YM3016 may be bad. Is there anywhere I should look first?
    Last edited by uncivil_enginee; 10-27-2020 at 01:54 AM.

  2. #2
    . uncivil_enginee's Avatar
    Join Date
    Oct 2016
    Location
    SoCal

    Posts
    13
    Just an update. I was able to get my hands on a combo card reader/head phone board this week, and make myself a wiring harness to connect it to my mv4. The static that I can hear at the speaker is also present at the head phones.

    I found the MV1 schematics posted on line, and the sound section appears to closely match what is on the mv4 board.

    So I think the issue may be at the YM3016 DAC, or one of the down stream 4558 amps. I am going to order some more parts and start trying to trace down the issue. My shop has cooled down in the mid-60s these past few days, and I have noticed that if I turn on the game, the static doesn't start until it has warmed up about 5 minutes. So I may be able to use an inverted can of compressed air to cool some chips down to try to isolate the problem further.

  3. #3
    . uncivil_enginee's Avatar
    Join Date
    Oct 2016
    Location
    SoCal

    Posts
    13
    Yet another update...
    I replaced the amp (its a LM324, not a 4558), and that didn't didn't help. So I had to wait for the YM3016 chip to come in from China. Well I got it yesterday, and swapped it in. Still no luck. After the game warmed up, the crackle was back. Next step would be to replace the YM2610. I am a bit nervous about replacing that one. I pulled up one trace replacing the YM3016, and had to run a jumper to get it to work. The YM2610 has about 4 times the number of legs to de-solder. I don't know if I can pull the chip without damaging the board traces.

    I am considering sending the board out for the repair. Who is working on Neo-Geo boards these days?

  4. #4
    Kula's Candy
    DasiyAge's Avatar
    Join Date
    Jun 2018
    Location
    United States

    Posts
    306
    Long shot but have you tried cleaning the volume sliders with something like deoxit d5? Give it a good rinse and scrub lightly with a toothbrush and then rinse it with deoxit again. I've fixed a lot of crackling sliders like this, although not for the MVS. Also does lowering the volume sliders a bit while playing get rid of the crackle or is it always crackling even with them turned all the way down?

  5. #5
    . uncivil_enginee's Avatar
    Join Date
    Oct 2016
    Location
    SoCal

    Posts
    13
    I read other posts that discussed the sliders, so last week I cleaned both sliders with a q-tip and rubbing alcohol. It didn't help any. Adjusting the sliders does not appear to make the crackle any bettor or worse.

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
  •