Hi all, I have an UMK3 board that I purchased a while ago that used to work fine and now is showing some graphical issues only when using the UMK3+ ROM set. When using the standard UMK3 ROM set in the board, the graphical issue isn't present at all, and the game plays fine with no issues. The sound also works fine regardless of what ROM set is installed in the board.
Once I swap in the UMK3+ game code ROMs (U54 and U63) and add the additional graphic ROMs in (U114-U117), and boot the board up, the graphical issues are present - see attached pics. The initial ROM check passes with the UMK3+ ROMs installed, but the graphical issues are still present, so I suspect there's something to do with the additional UMK3+ ROMs added in.
Not all graphical sprites are affected, just the sprites/pallets that are on the additional UMK3+ graphic ROMs, and the graphics that are affected have jail bars in them - see pics. I suspect this is due to the Midway Wolf board interleaving the UMK3+ graphics ROMs to produce a single image (happy to be corrected though).
The board has had some previous repairs done to it (battery clip and traces surrounding it & U15 IC replacement) prior to my purchase, although it may not have any relevance to this current issue, although I've included pictures of those repairs.
For the repairs that I've done, when I took out the board to play, the initial system ROM check indicated that the U37 IC was bad, so I replaced it, and it no longer flags as being bad - pic attached. I've also attached the Midway Wolf unit schematic here for posterity.
When having a look over the board and under the ROM IC sockets, I noticed there's a few exposed traces under the U108 socket, although U108 isn't populated for UMK3 or UMK3+ so not sure if it'll be an issue (or not), or indicates a more sinister issue with the board. I also noticed that the C124 capacitor (in pic U104-108-116.jpg) had one of its traces missing (pointing towards C83), and I've buzzed the other capacitors in the same area with the sockets and it looks like they're all connected to the ground plane on one side and to pin #16 on the other. Not sure if having one cap not connected makes a difference and it seems like they're all connected in parallel - happy to get some guidance on this if anyone knows.
I'm hoping someone has some sage advice on where I should look for issues next or where I should be focussing my efforts. I'm using a probe to test the various ROM ICs, but have not come up with anything useful/conclusive. I don't have a ROM reader/writer so I can't check the UMK3+ IC's, but considering the graphical ROM ICs are interleaved as per the Wolf unit schematic, it leads me to believe that the address or data pins/traces are at fault somewhere for the U114-U117 IC's as the graphical issue is only experienced with the UMK3+ ROMs only.
I suspect I'll need to remove the IC sockets, but am hoping to avoid that if possible if anyone has some typical issues that I could check first
Once I swap in the UMK3+ game code ROMs (U54 and U63) and add the additional graphic ROMs in (U114-U117), and boot the board up, the graphical issues are present - see attached pics. The initial ROM check passes with the UMK3+ ROMs installed, but the graphical issues are still present, so I suspect there's something to do with the additional UMK3+ ROMs added in.
Not all graphical sprites are affected, just the sprites/pallets that are on the additional UMK3+ graphic ROMs, and the graphics that are affected have jail bars in them - see pics. I suspect this is due to the Midway Wolf board interleaving the UMK3+ graphics ROMs to produce a single image (happy to be corrected though).
The board has had some previous repairs done to it (battery clip and traces surrounding it & U15 IC replacement) prior to my purchase, although it may not have any relevance to this current issue, although I've included pictures of those repairs.
For the repairs that I've done, when I took out the board to play, the initial system ROM check indicated that the U37 IC was bad, so I replaced it, and it no longer flags as being bad - pic attached. I've also attached the Midway Wolf unit schematic here for posterity.
When having a look over the board and under the ROM IC sockets, I noticed there's a few exposed traces under the U108 socket, although U108 isn't populated for UMK3 or UMK3+ so not sure if it'll be an issue (or not), or indicates a more sinister issue with the board. I also noticed that the C124 capacitor (in pic U104-108-116.jpg) had one of its traces missing (pointing towards C83), and I've buzzed the other capacitors in the same area with the sockets and it looks like they're all connected to the ground plane on one side and to pin #16 on the other. Not sure if having one cap not connected makes a difference and it seems like they're all connected in parallel - happy to get some guidance on this if anyone knows.
I'm hoping someone has some sage advice on where I should look for issues next or where I should be focussing my efforts. I'm using a probe to test the various ROM ICs, but have not come up with anything useful/conclusive. I don't have a ROM reader/writer so I can't check the UMK3+ IC's, but considering the graphical ROM ICs are interleaved as per the Wolf unit schematic, it leads me to believe that the address or data pins/traces are at fault somewhere for the U114-U117 IC's as the graphical issue is only experienced with the UMK3+ ROMs only.
I suspect I'll need to remove the IC sockets, but am hoping to avoid that if possible if anyone has some typical issues that I could check first
