Bow & Arrow SS Prototype

Bally Bow and Arrow Solid State Prototype

Back in the mid-70's, the major pinball machine manufacturers were scrambling to take advantage of the latest technological advance: the microprocessor. The idea of eliminating many pounds of relays, stepper units and score reels with "zero maintenance" electronics was too much of an opportunity to ignore. The first attempts at solid-state (SS) games were direct substitution of the electromechanical (EM) components with their transistorized equivalents. Once that part of the learning curve had been mastered, the designers started to explore the many new possibilities that the microprocessor would herald.

Bally's first SS pinball machine prototype was an EM Bally Flicker that was converted under contract with Dave Nutting & Associates. Nutting (with Nolan Bushnell who would later go on to form Atari) had pioneered the coin-op video game back in 1972 with Computer Space. This prototype apparently convinced Bally that the concept was feasible and they went on to develop their own set of SS electronics.

The next step was retrofitting 17 Bally Bow & Arrow EM pinball machines with the new board set, and putting them out on test. I have one of these prototypes, but it is not currently working. The board set is similar but not identicall to the boards used in the first-generation Bally SS machines. For one thing, the boards were mounted in the bottom of the cabinet, rather than in the head behind the backglass. This led to an unfortunate event with my CPU board. The CPU board even then had the infamous Nicad battery, used to keep track of high scores and game settings. Unfortunately, over time these batteries would leak their caustic chemicals over the circuit board, which would then eat away at component leads and the copper traces on the board. To make things worse, the CPU board in the prototype machines was mounted flat, so when the battery leaked, it spread its corrosion all over the circuit board.

So, I'm currently removing every component on the CPU board, and then the copper traces can be repaired, new sockets get installed for all chips, and corroded passive components get replaced. I've got some pictures of the game below, and I'll add more as the project progresses.

Click on any picture for a larger version

CPU board showing evil leaking Nicad battery