![TECH: How to replace the battery holder on a Williams System 11 CPU board | Museum of the Game Forums TECH: How to replace the battery holder on a Williams System 11 CPU board | Museum of the Game Forums](http://johnsarcade.com/images/whirlwind/close_up_1.jpg)
TECH: How to replace the battery holder on a Williams System 11 CPU board | Museum of the Game Forums
![MPU011A- This completely redesigned board replaces Williams System 11A & 11B MPU / Driver Boards part number D-11883-xxx (where xxx is the game number). MPU011A- This completely redesigned board replaces Williams System 11A & 11B MPU / Driver Boards part number D-11883-xxx (where xxx is the game number).](https://www.thepinballwizard.net/images/products/thumbs/pmpu-0004.jpg)
MPU011A- This completely redesigned board replaces Williams System 11A & 11B MPU / Driver Boards part number D-11883-xxx (where xxx is the game number).
![RD-MPU9211 Rottendog Williams System 11-11C MPU Board. Replaces Williams System 11, 11A, 11B, and 11C boards. Plug-and-play compatible. No batteries required. RD-MPU9211 Rottendog Williams System 11-11C MPU Board. Replaces Williams System 11, 11A, 11B, and 11C boards. Plug-and-play compatible. No batteries required.](https://www.pinballlife.com/mm5/graphics/00000001/4/RD-MPU9211_300x214.jpg)