ShootTheCore
Legendary
I purchased this Metal Slug 5 Neo Geo cartridge about a year ago. It worked perfectly fine when I first got it, but a few months later, it developed an issue where vertical lines would display over the entire playfield.

Neo Geo cartridges consist of two circuit boards - a CHAR board with all the graphics data and a PROG board with all the programming and sound data. This was a graphics issue, so my investigation focused on the CHAR board.

The culprit ended up being the SNK NEO-CMC multiplexor chip that manages the flow of data on the CHAR board. The SNK CHAFIO boards have a bad reputation for that chip failing.

Metal Slug 5 is an expensive game - the normal course of action is to track down an inexpensive game that uses the same board (King of Fighters 2003 in this case), and then swap the MS5 ROM chips over to the KoF board.
In my case, a helpful fellow on another forum sold me a spare MS5 CHAR board he had, so Problem Solved - for now at least.

Fingers crossed that the replacement board doesn't fail someday...I still have my spare defective CHAR board with the original ROMs that I can swap defective parts if need be.

Neo Geo cartridges consist of two circuit boards - a CHAR board with all the graphics data and a PROG board with all the programming and sound data. This was a graphics issue, so my investigation focused on the CHAR board.

The culprit ended up being the SNK NEO-CMC multiplexor chip that manages the flow of data on the CHAR board. The SNK CHAFIO boards have a bad reputation for that chip failing.

Metal Slug 5 is an expensive game - the normal course of action is to track down an inexpensive game that uses the same board (King of Fighters 2003 in this case), and then swap the MS5 ROM chips over to the KoF board.
In my case, a helpful fellow on another forum sold me a spare MS5 CHAR board he had, so Problem Solved - for now at least.

Fingers crossed that the replacement board doesn't fail someday...I still have my spare defective CHAR board with the original ROMs that I can swap defective parts if need be.