Which System 80 work the guide treats as mandatory
The guide covers System 80, 80A and 80B, from Spider-Man (1980) to Bone Busters (1989), and is aimed most at Black Hole and Haunted House. Its mandatory list is: inspect boards for defects, rebuild the power supply, deal with the CPU battery and its corrosion, fix the grounds on the CPU and driver boards, repin the connectors, update the pop bumper driver boards, add the pull-up resistors and check coil resistance.
Systems
Source: Bullet-Proofing Gottlieb System 80 Pinball from 1980 to 1989, Clay Harrell (pinrepair.com)