This is a solid-state re-make of the Bally's 1972 'Fireball' with new (similar) art, no zipper flippers, and some other rule changes. Also produced in Germany by Bally Wulff under license from Bally Midway as Bally Wulff's 1986 'Fireball Classic'. Uses the AS-2518-45 "Cheap Squeak" sound board. This game has been reported to have been factory-issued with either of these two MPUs: Bally MPU AS-2518-35 (6800) Bally MPU A080-91638-D000 (6802) Allan Reizman, Engineering Lab Supervisor at Bally from 1977 to 1983, tell us what he remembers about them:I remember discussing this with Doug Macdonald when the -35 board was revised. The original 6800 based MPU was developed in the mid 1970s. After 10 years some of the key components including the MC6800 chip itself were becoming hard to obtain or discontinued. A complete redesign was planned and eventually resulted in the 6803 based MPU however there was a backlog of production needs for the -35 board. To satisfy immediate demand for replacement parts and games in production a quick revision of the -35 to replace the discontinued IC components was rushed through and that I believe is the 6802 based board. I had left Bally at the time but over coffee one morning Doug told me they went to place orders for upcoming production and were surprised when some chips were no longer available. They wound up starting production with the -35 boards until the components were exhausted then put the 6802 board into production as a direct replacement as needed. An amusing side note is that when pinball production was in its heyday in the late 70s, Midway placed a huge order for components like displays and chips. After production died down in the early 80�s it was thought they had a lifetime supply of some things like 6 digit displays. It was thought the New Technology platform would replace the original board set before the chips ran out but apparently not all the chips were available at the end.