Fusion MVS converter minor graphical issues

[joethearachnid]

Hi all,

Got a bit of a frustrating yet minor problem here. I wanted a Fusion MVS converter but I managed to keep missing the drops from Furrtek so I decided to build some myself instead using the files available on Github. The build was a bit of an ordeal but I've so far managed to build 3 working adapters. My only problem is that all three have the same minor graphical issues, exactly the same across all the games I've tried. It looks like a couple of lines of sprite data are not loading in or intermittent and so there's missing lines on text etc. or flickering on moving sprites. It's most noticeable in Metal Slug on the character sprites but it's easier to photograph in Neo Turf Masters, see missing line on the text, slightly glitched power meter and missing lines on the spectator. All games play fine otherwise and these glitches are minor but hard to ignore once you spot them.






I had some connection issues at first with the converter so I've deep cleaned and tightened every contact on the AES (many times now) - there could possibly be a connection issue but I don't get any of these glitches using a 161-in-1 cart and the issues are the exact same across all three of my converters, not affected by wiggling the cart or anything like other poor connection issues. I checked both 5V input and the 3.3V regulator on the converter and both seem strong with no voltage drops and I'm using a Triad 3A 5V PSU on an early NEO-AES revision. I don't have another AES or an MVS to check the carts on but I did try reflowing EVERY connection on the Metal Slug cartridge and scrubbing the contacts to shiny perfection, but no change. Since the issues are the same on every one of my converters I don't think it's shoddy soldering either, unless I have incredible consistency with my soldering errors.
I get some kind of issues in all my MVS games (MS1, MS2, NTM, KoF'98).

I know the openly available Fusion converter is an earlier version than the current commercial version so I'm not sure if there are issues that have been fixed in the design since. I've seen very little information on anyone DIYing these so I don't know if if's a common issue. Can anyone with a Fusion converter, older or newer (or DIY), advise if they have any of these problems? I've emailed Furrtek directly a few weeks back but not had anything back.

 

[joethearachnid]

Tried a few more things:

• Rechecked and re-cleaned my copy of NTM, reflowed the CHA board for good measure.
• Tightened and cleaned the AES cartridge slot connectors a few more dozen times.
• Replaced the DC power jack on the AES since it looked tarnished/worn.
• Added some extra 100nf capacitors on the CHA board of the Fusion converter.
• Reflowed the cartridge slot contact pins on the AES in case of a poor connection somewhere.

No luck on any of them, sadly.

From what I can tell I seem to get glitches from both the C-ROM and S-ROM, since I get the missing lines on UI elements and character sprites. That implies that it's not just one address line that's faulty I think? I bought what was probably a set of clone CPLD chips from Aliexpress so I have no idea if they might be causing the issues but I don't want to shell out on genuine ones if the issue is elsewhere. I was hoping there was just a power issue but I can't see any problems there. I still can't nail down for certain if this is just an issue with this design of converter, an issue with my AES (which again, works fine with the 161-in-1), the MVS carts or something in the interface between them. Any comments at all are welcome.