Electronics tools needed for board work
Board work needs alligator clip leads, a soldering iron with 60/40 rosin-core solder, a desoldering tool, a digital multimeter and a logic probe. For connector pins use a proper hand crimper such as Molex WHT-1921 (11-01-0015) or Molex 63811-1000.
Systems
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part One, Clay Harrell (pinrepair.com)