Analogue CMVS slim audio timing issue?

[Synergy]

Hello everyone, i'm experiencing a weird issue with the audio timing on the game Over Top.

The audio is running crazy fast, anyone has any idea what the problem is? Sounds like the audio chip is overclocked or something.

Most games run fine, but this is one of the exceptions. I'm using the Darksoft flash cart, but also the 116-in-1 is having the same issue. Probably something wrong with the motherboard, but where to look?

Please see a video here:

Any help would be appreciated.

 

[avramce]

Hmm, thats interesting. No modifications done to the clock or anything? I have a handful of multicarts, official cart and 161 so I’ll check it out when I get home.

 

[Synergy]

Well, it has been revised/repaired recently and from what i understand the DAC chip had to be changed, but i don't think that's the issue otherwise i would have no sound at all.

From what i hear in Over Top, it seems that the Neo Geo splash screen and the intro are short sound clips sequenced but triggering too fast after each other (like a MOD file playing too fast if you're familiar with music sequencers).

I've been going through others games and i find more that are affected:

- Aero Fighters 2 & 3
- Aggressors of Dark Kombat
- Blue's Journey
- Crossed Swords
- Magician Lord (AES & MVS)
- Ninja Masters
- Over Top

Stopped there with checking. I've tried to look if there's a connection, but could not find one.

So if you have any clue where to look? A problem with the clock would be the most obvious to me, but if you have any suggestions please let me know.

Thanks!

 

[Neo-Alec]

Here's a possibly similar problem where the music was playing too slow. It ended up being a bad trace on the Z80.

View: https://youtu.be/zS6bBjhZ9dY?si=cKvVbNG96KBzZiOa

 

[Synergy]

Thanks for the suggestion! The weird thing is that not all games have the sped up audio, only a few and not even in all parts of the games. For instance, some of the background music of Over Top plays fine, other music is not.

I'll make sure the guy who's repairing my unit will look at the Z80 traces, just to be sure.

Thanks!