YOU MUST ORDER WITH ENIG FINISH AT 0.8MM THICKNESS!

This is an updated design of my flashable MBC3-based cartridge for the Game Boy. The MBC3 mapper improves a lot over the MBC1, and includes a real-time clock for everyone's favorite battery-sucking game.... Mary Kate and Ashley Pocket Planner! Oh, and Pokemon.

This MBC3 cartridge uses brand new M29F160 EEPROM chips and battery-backed SRAM.

This circuit board should cover most, if not all, MBC3 games. The features are as follows:

• Able to make games up to 2 MB in size, that use up to 256 Kbit of RAM
• Compatibility with all four of the popular Game Boy battery management ICs - MM1026, MM1134, BA6129, and BA6735
• The option to add battery backup to the cartridge *without* the need of the original battery management ICs
• Fully compatible with both the GBxCart RW and sanni's Open Source Cart Reader (OSCR) so you can transfer games and save files to and from the board

Along with reading the GitHub repo IN FULL, please review the following before purchasing:

• To use this board, you need to have an original Game Boy game that uses an MBC5 mapper chip.
• You will need to remove the MBC5 from your donor cartridge for use on this board. This will require a hot air rework station or a hot plate. There's a list below of other parts you can re-use from the donor cartridge.
• When soldering parts on, it's a good idea to put kapton tape or otherwise cover the bottom cartridge edge. You do not want to get solder on the cartridge contacts.
• I am not responsible for any damage you do to your self or your property. Attempt this project at your own risk.
• I do not guarantee design compatibility. You may encounter issues with certain games. There is also a chance I have made an error in the design or the BOM - if this is the case, I will do everything I can to address the problem as quickly as possible.
• If you are using this board to make games other than for personal use, you must have permission from the originator to use and distribute any ROM images or other related material. You are responsible for making sure you adhere to any license requirements.
• DO NOT use my circuit boards for profiting from stolen work - this especially includes homebrew content, ROM hacks, and using fan-made labels without permission from the originator. Support original creators!

All gerbers and source files can be found in the GitHub repo, as this project is fully open source with attribution. Please view the repository for BOM information.

https://github.com/MouseBiteLabs/Game-Boy-Cartridges/tree/main/MBC3%20(Type%20A%2C%20SRAM)