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Neo GEO 2 Slots MVS sound distortion, please help if you can.

TobyRieper

TobyRieper

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I have purchased 2, 2 slots. 1 MV2FS and the other MV2-01.

They are both experiencing this odd sound distortion, crackling noises, farting, Poppin it's horrible. The start up jingle plays fine though. Here is a video ( i apologize for the bad quality)


Should I start off with a simple cap replacement around the audio section? Or could it be I need a new YM3016D chip?
I should clear the backup ram first I take it. Didn't think of that till now.
Cheers :)
 
Last edited:
Is your cab wired for MVS, these 2 slots are not Jamma? If your wiring is MVS please ignore.
 
I've tested the 2 slots on my Jamma cab that previously had a fully functioning 1 slot MVS. I get the audio distortion from the headphone socket as well.
 
Thanks for your reply @nem Oh indeed I expected odd audio but nothing like the distortion I have now. I also took the audio directly from the headphone cable and it still sounded awful.
I have updated the video link in the original post. Hopefully this one will work :)
It is not the video I took, its from the seller.
 
ok, so update on the 2Slot situation. I've changed all the caps apart from the 10 or so 4.7uf (they are arriving in the mail.

MV2-A - Slot 2 - first sounded distorted, Sound test in Hardware was fine. Re aligned cart pins for better contact..now works fine.

Slot 1 - Did exactly the same but the distortion did not change. Here is a video I took highlighting the audio..


MV2F - Both slots put out awful sound distortion but you can only hear it through the headphone socket, there is no audio output from the Speakers. Have re aligned cart pins, no change. Sound test was fine through the headphones.

On both machines I used Unibios 4.0, cleared ram etc.

If anyone has any ideas as to what I should check next that would be awesome. I spend around 12 hours today trying to find the problem.
 
Update...
Successfully repaired MV2F today. After hours checking signals and continuity it turns out Pin 49 on cart slot 1,A wasn't connected to NEO-E0 pin 12.
I only found this out by desoldering all the cartridge slots and checking the traces (some run under the plastic of the slots).

It was so tiny you couldn't see it, a trace was separated from a pin via oh so slightly.
Hopefully it's a similar problem with the next board..onwards and upwards :)
 
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