Repair | Fixing a Mario IV cartridge

Ric got hold of a Mario Bros IV cartridge, but the cartridge shell was in bad shape.

Later on, we discovered the game wasn’t working.
No matter how good I cleaned the connector, none of my consoles was booting this game.
Time do debug the cartridge!

First I had to identify what chip does what.
As you can see in the image below, I wrote it on the chips with a marker.
Mario 4 - Cartridge

After I found out what chips was what, it was time to debug it.
I did it by dumping the rom content with my Chiplab rom reader/programmer and then looking at the rom content.
With that done, I tried compiling the romdumps into an iNES rom (which emulators use) and found out the PRG and CHR roms were good….hmmm then it has to do something with the board. MORE DEBUGGING!

I started testing the board connections, and all seemed fine, so it had to be either the memory mapper chip that was busted (could be, those clone mappers are notorious when it comes to failing) or the other little chip on top (which combines the 2 PRG roms)

After almost giving up and Ric wanting to send me another donor board, I tried one more thing…stay tuned for the video!