Xenon and later: -54 power supply in the cabinet
From Xenon (late 1980) the power supply is the AS-2518-54, moved to the lower cabinet with different connectors, and most games use the -61 Squawk & Talk sound module. From X's & O's (1984) the Cheap Squeak sound board M-051-00114-B045 (or B044) is used.
Systems
Related tips
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)