Description

The Famicom GPM Expansion Port Switcher Upgrade lets you switch the expansion controllers between internal and external modes on any Famicom with a GPM motherboard.

Japanese Famicom consoles have a known issue: some western games don’t work properly with controllers connected to the expansion port. This happens because the NES never had this port, so some developers ignored it entirely.

Notable Games Affected:

• Arkanoid II
• Battletoads
• Dragon’s Lair
• Paperboy
• Pinball
• RoboCop 2/3
• Star Force
• Super Mario Bros. USA
• Snake Rattle’n’Roll
• Terminator 1/2
• Tetris (Tengen)
• Zelda II – The Adventure of Link

Installing this upgrade requires console repair skills. You’ll need to solder and drill multiple holes in your motherboard. Keep this in mind before you begin.

The kit includes fully assembled upgrade boards and a drilling jig. You’ll also need a few small wires (not included) to finish the installation.

This upgrade was brilliantly designed by Jeff Chen (jeffqchen on GitHub).