Folks...I will have for sale for $10 brand new Lithium Battery boards to easily convert your Bally/Williams/Stern machines 1977 to 1984, and Williams to 1999, Bally later games 1988 to 1999. (Not made yet for later Stern...soon!), to safe leak free Lithium...includes battery and new blocking diode too...super easy to install...I will be there Friday Afternoon. walking around with them...here is a video showing them! Todd from TNT Amusements