Graphics corruption on MV1B

[bodgit]

I've got a weird problem on my MV1B that I've noticed with the homebrew title Hypernoid, part of the ball sprite is corrupted like this:

Some observations:

• It doesn't always happen, not 100% sure if it's a function of the machine being powered up for a while and something is warming up
• As the ball moves up the screen, it clears up, then as it moves back down the screen it can reappear
• If I switch to another game, I don't see a similar problem; I've left Xeno Crisis running in attract for a long time and that doesn't show anything odd
• I've tried running the diagnostic BIOS and that doesn't find any faults

Anyone have any other ideas? I'm in touch with the developer and they are unable to reproduce it on an MV1B which makes me think I have a subtle hardware fault somewhere...

 

[Niko]

Being able to see a bigger version of the image would help or even a video of how the corruption changes as the ball moves.

How are you booting the game? Did you make a cartridge or are you using a flash cart?

This seems more of a ROM/Cart issue IMO.

 

[bodgit]

Here's a video:

View: https://youtu.be/qfJUyh6V2uA


I'm running the game from a NeoSD, I've tried putting it in different flash slots and it still happens so I think that's ruled out.

It only seems to happen in the lower section of the screen. It definitely gets worse the longer the machine has been on for, if I power up from cold it's fine, but leave it in attract for 20-30 minutes and it'll start acting up. However if I immediately boot into a different game, no obvious corruption.

 

[Niko]

If you're not experiencing issues in any other games, then I'm going to go out on a limb here and say its something with the game itself. Could also have something to do with the NeoSD or maybe the BIOS version. Either way its hard to point at the motherboard when the only thing displaying any issues is a homebrew title.

 

[djsheep]

Originally, there were somewhat similar graphical issues when the team was testing the game for the last Firmware for the Darksoft AES/MVS cart. The game developer helped us pinpoint the issues.

I'd say you're better bringing your problem up with actual users of that "other" cart on their forums or directly with them. It's not related to the Darksoft cart.

It works perfectly on the superior cart on both AES and MVS systems.

 

[bodgit]

Thanks for the replies.

I agree if the game did this from the get-go then it would point to either a fault of the game, or firmware on the flashcart, etc. however because it seems to be a function of how long the MVS has been powered on (rather than just the game itself, I can warm up the MVS with a different game and then switch to Hypernoid and I immediately see the fault) then it suggests to me that some component somewhere, either in the MVS or possibly the flashcart, is on the fritz rather than a bug in the game.

As to not seeing it in other games, maybe I've just not tried enough other games. I'll go through the library and see if I can find another one that triggers this. BTW because it was mentioned, the BIOS is a UniBIOS 4.0 in a Neo BIOS Masta VMC, the original MV1B BIOS is disabled.

I suppose I was just asking if anyone has seen this sort of thing before and the diagnosis is either "it's a RAM chip, you can swap that out", or "it's a custom IC on the MVS, you're better off finding a replacement system", etc.

Either way, finding another MVS is maybe the cheapest way to rule out or confirm things.