Check the mating connectors after a corrosion repair

If the MPU had corrosion, the pins inside the cable housings may be corroded as well; replace any that are not clean and shiny. J4 and J1 are the most affected. Pry up header bases to look underneath.

Systems

• Bally MPU AS-2518-17
• Bally MPU AS-2518-35
• Stern MPU-100
• Stern MPU-200

Related tips

• AS2518-18/-49 connector functions
• The connectors that burn most often
• Which boards use .156" and .100" connectors
• Key new connector housings
• Connector housings and pins to keep on hand
• Replace burnt connectors on both halves
• Pre-Xenon rectifier board outputs by connector
• No solenoids and no game start: corroded power board connector

Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)