In today’s episode, I go over some standard, recommended modifications to the Bally-35 series solenoid driver board. There are over 60 popular pinball games that use this hardware setup and these quick modifications will help make the game run better and more-reliably. They involve adding three jumpers to the board. Whenever I have a chance to work on one of these boards, I do these mods.
Here are some front and back pictures of both Bally and Stern Solenoid driver boards. The black wires are the mods. The other colored wires are done by operators having to do with the coil lockout relay.