Neo Geo MVS 4-slot + supergun scrambled screen

Hi guys,

So I decided to build a 4-slot MVS arcade cabinet and, after purchasing a supergun and a MVS 4-slot, I hooked everything up to test out the heart of the cabinet before I installed it and I am getting a scrambled screen and no sound out of the supergun.

See pics.




On a second monitor I tried I was getting no image at all.

I thought it might be the connector edge on the MVS 4 slot so cleaned it with isopropyl, but despite taking off some dirt it hasn't made a difference.

Is there anyone here who has seen this before and can recommend what it could be.

I've been using a couple of PAL TVs for this. Is the supergun at fault?

It is annoying as I can see the crosshatch but it is slides across the screen repeatedly and is garbled.

Any help would be much appreciated.

So I got the image working by running the scart out of the supergun through a framemeister. I thought it could be a sync issue maybe?



I do not have sound coming out of the supergun's 5mm audio jack, though, and there is no sound over scart.

Do I need an adaptor or something for this harness?

Again, any info would be much appreciated.

And... I got it all working. Image fixed with Framemeister sync tweaks, and audio fixed with cleaning harness.

Happy to have the core working now. Will post pictures of the cabinet when it is up and running.

After some cleaning of the cart slots all 4 are now operational.

Keep in mind a 4-slot is not wired exactly like JAMMA. Careful not to cause any damage with that supergun.

Thanks Joe, I'll keep that in mind. I'm trying to be as careful as possible and have a basic understanding of the differences in wiring and power demands etc.

BTW, when I select free play in the dips is there a way to bypass having to have a credit in before game carts can be switched between? Right now I have to force a coin insert before I can select scroll through the carts.

There should be an option in the bios under the soft dip configuration section.

Thanks ack, I'll take a look.

Hi all. Said I would come back when the 4-slot was installed and the cabinet is up and running and here we are. Thanks to everyone who offered help and support.

I’ve installed Unibios 4.0, too, and did magage to find the free play without credit option in the dips software menu, so thanks to ack again for the direction on that.

There is also hard DIP 7 on the MVS logic board which when turned on enables free play.

Thanks HMG. Yeah, I had 7 flicked, which enabled free play, but I still had to force a credit insert for the 4 slot to allow me to switch between carts. With this board I needed to also enable a setting that would allow me to switch between games without having to a force a credit. Now I can jus turn it on and cycle the carts with select without credit.