Bally -35 MPU games with the -18 supply
From Lost World (1978) the -35 MPU replaced the -17. The -18 power supply carried on, first with the -32 sound module (to Supersonic), then the -50 (Star Trek to Dolly Parton), then the -51 (Space Invaders to Frontier), when 7 digit player displays arrived with a 6 digit credit/ball display.
Systems
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)