The controller port boards on Dreamcast consoles are known to fail. This is due to multiple issues, most commonly a failing capacitor or dead battery.
This kit has everything you need to fix your dead controller port board.
The coin battery holder replaces the default battery and allows you to easily slide out and replace cell batteries when they die instead of re-soldering a new one in. The fuse is reusable; if it blows, simply power off the console and turn it back on to resume playing. The capacitor replaces the likely old and leaking existing capacitor on your console.
Note: Requires soldering and disassembly of console.