Even tiny corrosion can short the switch matrix
Corrosion too fine to see under magnification can bridge traces, header pins or DIP switch pins, shorting switch matrix lines or power inputs. Clean the whole battery area, under connector bases and around the DIP switches.
Systems
Related tips
- Switch faults from corrosion under MPU J2 or J3
- Repairing battery corrosion on the MPU
- U8 (5101) connections for ringing out corrosion damage
- Reset section parts typically ruined by battery corrosion
- Repair battery corrosion before chasing MPU flash codes
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)