I drummed up some kits to see if anyone was interested. Comes with the battery, battery holder, jumper wire, and step-by-step instructions on a PDF for those who may not know how to install one. Works for Defender, Stargate, Robotron 2084, Joust, Sinistar, Bubbles, and Splat. Likely the pinballs as well, but I havent tried it myself yet. $10 shipped per kit 
