Got a lot of broken MVS carts, need help repairing them

[Evan]

I recently came into possession of many broken mvs carts for a good price. I am working on fixing them, and a good amount seem to have issues with roms. Attached are each cart and an image and diagnosis. For all of these I was wondering what eprom I need to buy to replace each type of chip and how I know which type to replace each one with. Also all games contacts have been deep cleaned.

Real Bout Fatal Fury:
Cart seems to just have a bad p rom(s). Loads up but crashes on the attract mode. I was able to do a CRC check and it says rom bank 1 is ng. Anyone know which p rom this is?

KOF 94:
Doesn't boot at all. I was able to use the char board with another games prog board and it was able to run (corrupted graphics of course). This leads me to suspect a bad p rom.

KOF 96:
Game boots, however it is stuck in a Neo Geo logo boot. Also no graphics are displayed at all. This leads me to suspect multiple issues. I was able to use the prog board with another games char board to test the CRC and the last rom bank was NG. The game seems to be a previous official SNK repair.

KOF 95:
This game doesn't boot at all. I have a working copy of KOF 95 and so I tested it and the char board is good, suspect a bad p rom.

Metal Slug:
P rom has visible rust on multiple legs. I assume this has destroyed the chip internally. So replacing the p rom seems like the fix.

Super Sidekicks 3:
Char board is good, have another cart I tested it with. Game doesn't boot at all. Suspected bad p rom.

KOF 99:
Char board is good, tested it with another working cart. Game graphics are fine however the audio is completely garbled. Sometimes certain sounds like there beep after selecting a character sound right but the music itself is corrupted. Not sure what could be the problem here

Double Dragon:
Game sometimes boots but then goes to a pure white screen. Neo Geo logo on unibios is completely garbled. No sound at all.

 

[twistedsymphony]

Nice troubleshooting! that should be some quick work.

I bought a lot of 18 non-working KOF97 carts a while back... I managed to make 3 good set from just swapping around boards and cleaning.
of the remaining sets all of them had sound glitches due to bad PCM chip and I had a couple of boards with bad graphics.

a lot of MVS cart repairs are pretty simple. I've seen quite a few carts that were repaird just by a reflow on the pins. Since the through holes on many of these carts are single sided they're prone to cracked solder joints (and also prone to lifted traces around the holes too)

 

[fraggle200]

Not sure if the pics were taken before any work was done but a lot of the edge connectors look pretty dirty.

I've had a few carts in my collection that have given me some weird issues when I've received them and once the edge connectors are thoroughly Qtipped with IPA and then rubbed down with an eraser to get rid of all oxidization most of them have went away. After that it's just been a case of checking all the solder work to make sure there's no dry joints or corroded traces.

I got a Shock Troopers that was NOS and it had messed up sprites on the title screen. turns out it was a corroded trace on it, you could barely see it as well but wasn't till I checked continuity on it, that it was confirmed. The cart was immaculate otherwise. As this trace issue was barely visible as it was right at the pin, I took a bit of a punt on this potentially being the cause but had nothing else to go on at the time and as it was NOS, surely it couldn't be a bad rom?!?!?
Don't discount anything that may seem insignificant. It helped that it was a gfx issue so it had to be a C Rom that was the problem. (see link below to help narrow this stuff down if you're unsure)

With that being said, I'd make sure all this kind of stuff is done, as well as reflowing all solder joints, before settling on bad roms as being the issue. if you have thoroughly went through each cart and by the looks of things above, you're on the right track by swapping boards in and running CRC checks. the next step is to eliminate bad roms.

this is a great resource that may help https://wiki.neogeodev.org/index.php?title=Category:Cartridge_systems