On System 9 boards, the SRAM is located at U18 and on the System 11 boards, at U25. This mod will not work with those boards so a 6264 NVRAM will be required. The Ultimate NVRAM is only available in the 5101, 6116 or 6264 format.
MCR 6116 NVRAM Battery Eliminator for Bally/Midway MCR Video Arcade Games
6116 NVRAM Battery Eliminator for Bally, Williams & Laser War Pinball Machines
Ultimate 5114 NVRAM Battery Eliminator - Dual Mode Option for Arcade Games
Ultimate 6264 NVRAM Battery Eliminator - Dual Mode Option - For Pinball Machines
Ultimate Dual CE 5101 NVRAM Battery Eliminator - With two Configurations
5101 NVRAM Battery Eliminator for Stern Classic MPU-200 Boards