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[SOLVED] MVS one slot audio dropping out

While waiting for the diagnostics BIOS, I decided to test more games. After about 20 minutes in attract mode, this is what I get with Metal Slug X. KOF96/98/2000/2002 all were fine.
 

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kikaso said:
While waiting for the diagnostics BIOS, I decided to test more games. After about 20 minutes in attract mode, this is what I get with Metal Slug X. KOF96/98/2000/2002 all were fine.
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curious if you have checked the voltage on the 5V rail while the board is powered on? I would check the board side to verify its at/near 5V. The Metal Slug X picture seems to point to issues beyond just sound cutting out.
 
Yeah the MV1FZ has convenient test pads for reading 5V. That was the first thing I checked. Thanks
 
I pulled the YM2610 chip and soldered in a socket to prepare for a new chip and more testing. I’m going to spend the rest of my evening making sure I didn’t pull any traces but it looks good so far.
 

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ack said:
The Metal Slug X picture seems to point to issues beyond just sound cutting out.
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A buddy loaned me a MV1F one slot and the sound issues, of course, aren’t ARE present on his board, additionally, Metal Slug X glitched out after 15 minutes or so on the loaner MV1F as seen above. I double checked the voltage and that’s fine. I tested on a cabinet and supergun—same results. It’s possible that the ROM file I’m running on the multi cart is corrupted so I’m borrowing a known working Metal Slug X cart to do some more testing.

In the meantime, I ordered a new YM2610 to see if that solves the audio issues on the MV1FZ.

EDIT: both motherboards are having same audio issues and glitching on Metal Slug X. I’m ready to rule out cartridges and the motherboards as faulty unless I have awful luck? That leaves the arcade cabinet and PVM supergun setup. The voltages are 5V tested on two different multimeters. What’s happening?!
 
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A friend pointed out that the common link between motherboards, game carts, and cabinet and supergun was the RECO button remapper. I removed the RECO but still losing audio after 20 minutes 😞
 
Another update:

I played Metal Slug, Neo Turf Masters, and Metal Slug X all the way through to the end. Took me about 30-45 minutes per game—no issues whatsoever. After getting to the end, I let the game loop in attract mode and the sound stayed on. Further, Metal Slug X didn’t glitch out after more than 45 minutes of attract loop after beating the game.

It seems that the games lose audio (or glitch out In the case of Metal Slug X) if I turn them on and let them loop in attract mode for 20 minutes or more. If I insert a credit at any point while it still has audio, the game plays fine with no issues. If I insert a credit after audio is lost, I have to power cycle to get audio back.

I’m issuing a bounty; anyone who can help me solve this gets a free Fujiyama Buster / Shogun Warrior arcade board. The game works fine but I never got the kicks sorted out. I have a couple of harnesses but I never put the time into figuring it out. Free shipping to the US but if international, I’ll split the shipping costs with you.

Solving this mystery could mean I have no more audio issues and/or glitches or it could mean finding evidence that certain Neo Geo games losing audio if left in attract mode is a known and documented problem.
 
Do you have a UniBIOS installed? UniBIOS 4.0 has been doing some weird shit on boards sent into my shop like a 4 slot with no audio on Samurai Shodown and no audio on slots 2 and 4 on another board. Leave the carts in the slots while lifting the top board up and changing the BIOS then plugging it back to the bottom board gives you audio back. Repeating with reinstalling the UniBIOS and audio goes out again. Crazy stuff. I downgraded one to a UniBIOS 3.3 and reset the backup RAM on the other.
 
channelmaniac said:
Do you have a UniBIOS installed? UniBIOS 4.0 has been doing some weird shit on boards sent into my shop like a 4 slot with no audio on Samurai Shodown and no audio on slots 2 and 4 on another board. Leave the carts in the slots while lifting the top board up and changing the BIOS then plugging it back to the bottom board gives you audio back. Repeating with reinstalling the UniBIOS and audio goes out again. Crazy stuff. I downgraded one to a UniBIOS 3.3 and reset the backup RAM on the other.
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I do have unibios 4.0 on both. I’ll put the original Japan bios in and do some testing tonight.
 
channelmaniac said:
Do you have a UniBIOS installed? UniBIOS 4.0 has been doing some weird shit on boards sent into my shop like a 4 slot with no audio on Samurai Shodown and no audio on slots 2 and 4 on another board. Leave the carts in the slots while lifting the top board up and changing the BIOS then plugging it back to the bottom board gives you audio back. Repeating with reinstalling the UniBIOS and audio goes out again. Crazy stuff. I downgraded one to a UniBIOS 3.3 and reset the backup RAM on the other.
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Swapped in the original Japanese BIOS and Metal Slug has been running for two hours with no audio issues. Seems like the UniBIOS was causing the audio issues. I’m testing Metal Slug X now since that game was also having issues, (graphical not audio) but I’m confident that it was UniBIOS 4.0 that was responsible for the errors.

@channelmaniac PM me your address; you’re the proud owner of a kusoge.
 

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Great find! Glad you figured this out. Now to test my boards in attract mode…

Does anyone know if razoola still patches/updates?
 
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