Removing corroded chip sockets

Steps

• On a black open-frame socket, pry the plastic frame up carefully without scraping traces; the pins stay in the board.
• If the pins are clean, push the frame back on. If they are grey or green, the whole socket must go.
• Brown or black closed-frame sockets cannot be pried apart; they all need replacing on any Bally MPU.
• Heat each pin from the solder side, where corrosion is usually lighter, and draw it out using needle-nose pliers.
• Desolder the holes, adding fresh solder first if the old will not flow.

Systems

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

Related tips

• Corrosion under MPU J4 can destroy every chip
• Cut the original MPU battery off right away
• Reset section parts typically ruined by battery corrosion
• Repairing battery corrosion on the MPU
• Fitting a remote AA battery pack
• Installing a memory back-up capacitor
• Memory cap or battery does not keep scores
• Repair battery corrosion before chasing MPU flash codes

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