FD1094 and FD1089 suicide battery
Some System 16, System 18 and System 24 boards by Sega have custom cpus labeled FD1094 or FD1089. These are 68000 processor cores with a battery and encryption keys which are used to decrypt the game at run-time. Unfortunately these batteries eventually die out and the game is rendered useless.
There are two ways of preventing this form happening. You can replace the battery inside of these, and keep doing so every 5 years or so in order to keep them as original as possible; or you can buy/build a kit to replace the encrypted ROMs with unencrypted ones and change the FD processor for a standard 68000 one.
Please refer to the external links section for information on these methods.
- Sega Resurrection A site that sells kits to revive dead Sega boards
- The Dead Battery Society Site with information on suicide arcade games
- JAMMA Nation X has a tutorial to change an FD processor battery, check under Other->Misc.
- Charles MacDonald FD1094 Game Conversion Information on how to decrypt these games by yourself