Problem with motherboard mvs1f

[konrad]

When the characters move away the zoom is lower than it should be I am attaching an image.

 

[konrad]

Can someone tell me what it could be?

 

[Neo Alec]

That looks weird. I think a video might better illustrate the problem.

Is there a problem with any other games you've tested?

 

[konrad]

It happens in games where there is zoom, when the characters move away from the screen it is as if the floor of the game went a little lower.

 

[konrad]

The logo NeoGeo move little Up y down.

 

[konrad]

Here this problem the pinnout solved

 

[konrad]

Ok thanks for listen.

 

[Neo Alec]

This is now fixed?

It's a strange problem I've never seen before.

 

[konrad]

The problem persists, I hope it is not the graphics chip.

 

[Neo Alec]

Okay, thanks for clarification.

Can you make a video of the zooming problem?

 

[konrad]

How can you upload videos here, it doesn't accept mp4 format?

 

[Neo Alec]

You should upload the video to Youtube or Google Drive, or another. Post the link to the video here.

 

[konrad]

https://drive.google.com/file/d/16pBL3Jq4eedj86QpO6IwWcZo7JjZES1N/view?usp=drivesdk

 

[konrad]

https://drive.google.com/file/d/16qhFVnwd8gKllvF1YIYKm-B3hMznoYJs/view?usp=drivesdk

 

[konrad]

https://drive.google.com/file/d/16syMEGg2B-5VsOKsWpOkQVheRiBbb3IQ/view?usp=drivesdk

 

[Neo Alec]

You'll need to go on google drive and set all of those files to public (anyone with the link). Right now they're private and I can't see them.

 

[konrad]

You can see them now.

 

[Neo Alec]

That's really weird! In the last video I can see how the screen kind of snaps to the wrong place after it's done zooming.

 

[city41]

The diagnostic bios might shed some light. A total guess but possibly some memory cells in main work ram have gone bad and SS2 just happens to use that memory and other games don't.

 

[konrad]

Thanks for listening.

 

[city41]

Sorry man, this one is bizarre.

 

[maki]

AFAIK the NeoGeo doesn't calculate zoom on sprites, instead it uses a lookup table which is in the L0 ROM.

L0 ROM - NeoGeo Development Wiki

wiki.neogeodev.org

I'd focus on that, check all traces/connections etc., replace it if everything checks out.

 

[konrad]

Thanks maki I'll look at it. greetings

 

[konrad]

Is there a way to check with a tester if the chip is broken? greetings

 

[ebinsugewa]

Do you have an EPROM reader? If not, not really. You could use the reader to compare the actual contents of your chip to the known correct values.

It would be easiest to just swap one from another board, but you obviously may not have access to an extra.

Ultimately, if your chip verifies as good in a reader/you swap a working one from another board onto yours and see no change, you probably have an addressing/data line problem that needs to be figured out. How to do that is really beyond the scope of explaining here, unfortunately. If you have a logic probe, you can start to maybe narrow it down.