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Thread: 4-Slot MV4FT No sound in-game?

  1. #1
    . avramce's Avatar
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    4-Slot MV4FT No sound in-game?

    Hi all, I just received a new 4-slot board to try with my cabinet, and I was pretty pleased when I realized that all 4 slots are able to read my games with no graphical issues.
    However, after rewiring my cabinet from JAMMA to MVS audio pinouts, I realized that none of the games have audio. So far, I have tested the pots, looked for visible damage in the audio area of the board, and reflowed a few components for good measure, but still have no luck recovering the audio.

    In the hardware test menu, I noted that I was able to get both a left right and center tones on both my cab and my headphone ports, so I'm coming to the conclusion that something is wrong with how my board is reading audio from my carts.

    I'm still relatively new to MVS troubleshooting, but if a problem like this happens across all four slots, does that imply something would possibly be wrong with my Z80? Upon closer inspection, it appears the someone had worked on the Z80 area of the board (very poorly I might add). I wicked off some of the excess solder on the Z80 pins a reflowed, then checked the traces for continuity, and all looked good, however, still not getting sound.

    At this point, would there be any reason to consider replacing the Z80? I have a few other boards I could pull one from if need be. I ordered a Neodiag chip from eBay and will be trying that out when that arrives.

  2. #2
    Geese's Thug
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    You should try clearing your backup ram and see if it fixes the issue.

    In order to test the z80 with the diag rom you will need cart that has the diag m1 rom on it.

  3. #3
    . avramce's Avatar
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    Heya Ack, thanks for the suggestion. I have cleared the RAM and still seem to be hitting the same issue. At this point, I have removed the Z80 and socketed two separate boards and confirmed that the Z80 from this problem board works without issues on a separate board. For fun, I swapped BIOS, but that didn't appear to do anything for the issue.

    So now I know the Z80 isn't at fault, and have confirmed that all my carts produce sound on other boards

  4. #4
    JammaNationX
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    Are you sure you rewired the speakers correctly and used the correct impedance speakers? If so, make sure you check the volume sliders and apply fader lube to them as well.

  5. #5
    . avramce's Avatar
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    Quote Originally Posted by Xian Xi View Post
    Are you sure you rewired the speakers correctly and used the correct impedance speakers? If so, make sure you check the volume sliders and apply fader lube to them as well.
    Yep yep, I confirmed that I get the full range of the 1K pot for both the headphone and speaker outputs, and confirmed that I have the speakers wired correctly with my spare MV4 board (another board I'm trying to repair with corrupted graphics but working sound).

    Hardware test is able to put out left, right and center channels fine on both cab speakers and headphones, and the volume responses correctly when I slide the pots.

  6. #6

    Neo Alec's Avatar
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    Definitely test with the diagnostic bios like ack suggested and report back.

  7. #7
    . avramce's Avatar
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    Hmm, got the diagnostic bios, all tests passed. Unfortunately, the seller only shipped me a single EEPROM with the SP1 chipset, so I don't have the M1 to confirm the Z80 functionality. Like I mentioned before, I did pop off the Z80 and test it on another board and saw no issues with the sound there, is it still worth hunting down a M1 rom to use in conjunction with the SP1?

    Was reading on the JNX tutorial pages - Could there possibly be something wrong with the YM2610? I visibly did not see any worn traces, but will check for continuity there tonight.

  8. #8
    . avramce's Avatar
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    Finally got around to buying a EPROM flasher and made myself a M1 diagnostic set and managed to get it working on a spare bootleg cart board. At this point, I have confirmed that on my working 1-slot that my sp1 and m1 combo work, as it was able to do a complete Z80 test without issue.

    Moving onto the problem board mentioned in this post. I have confirmed that audio is still messed up ingame, and that the board can still produce sound in the hardware test menu (swapped the YM2610 and Z80 from a known working board to test) and the Z80 tests will consistently report:

    Z80 dead / errored/ comm. issue
    Expected: C3
    Actual: 01

    I've been reading up on the distro page for the NeoDiag roms, and cannot make sense on how to approach fixing this issue.

  9. #9
    Cham Cham's Banana
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    http://www.neo-geo.com/forums/showth...Z80-ERROR-quot
    Here's a thread where OP dug deep into surrounding chips that communicate with Z80. Post #11 would be my starting point

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