In for repair is a Seibu Kaihatsu SPI mainboard (V2.0 Revision) and a Raiden Fighters 2 game cartridge.
The SPI mainboard wouldn’t boot – on powerup, it would display a generic “Checksum Error” message.
This is a common problem with the SPI platform. The SPI mainboard and game carts are region coded. If the cart region doesn’t match the mainboard region then you’ll see this error. Additionally, when a game cartridge is accepted, portions of it are flashed to chips on the mainboard. If something goes wrong during the flash process, the mainboard’s region code can be lost, causing it to no longer work with any game.
Happily, Trap15 created a tool called SPI Revive that can be used to write a new region code onto an SPI mainboard. I connected my SPI Revive cartridge, and it shows that the region code for this board is “zero” meaning that it was indeed bricked. I told SPI Revive to write the Japan region code to the board, which it did successfully.
After reconnecting the Raiden Fighters 2 cart, the board started up successfully, flashed itself to the mainboard successfully, and then prompted to restart. After restarting, the game boots up and runs fine, but with “jailbar” lines of corruption running through the sprites.
This is another common issue with game cartridges on this platform. There are several SMD ROMs and a large SMD custom chip. Not much solder was used at the factory and over time, some of the chip legs can detach from their solder pads, breaking the connection.
One way to test for this problem is to press on various chips on the PCB and watch the screen to see if the graphics change. I used a plastic spudger and noticed the jail bars would flicker when I used it to press on ROM chips in the OBJ section. I reflowed the solder on them.
Afterward, the game boots up and runs fine with crisp, clear graphics and sound. The final touch is applying reflective stickers to cover the exposed windows on the two EPROMs missing them on the game cart. A successful repair!
