U8 (5101) connections for ringing out corrosion damage
Address lines: U8 pin 1 to U7-20 and U6-5; pin 2 to U7-21, U6-6; pin 3 to U7-22, U6-7, U11-35; pin 4 to U7-23, U6-8, U11-36; pin 5 to U7-18, U6-3; pin 6 to U7-17, U6-2; pin 7 to U7-15, U6-1, U11-24; pin 21 to U7-19, U6-4, U11-22. Pin 8 is ground and pin 22 is +5 V. Data pins are paired (9-10, 11-12, 13-14, 15-16) and go to U7 pins 6-9, U6 pins 14-17 and U11 pins 29-26. Pin 17 goes to U9 pin 40 and U11 pin 34; pin 18 to U18 pin 6; pin 19 to U17 pin 8; pin 20 (R/W) to U7-16, U11-21, U9-34 and U18-7.
Systems
Related tips
- Repairing battery corrosion on the MPU
- Reset section parts typically ruined by battery corrosion
- Repair battery corrosion before chasing MPU flash codes
- Corrosion under MPU J4 can destroy every chip
- Switch faults from corrosion under MPU J2 or J3
- Cut the original MPU battery off right away
- Removing corroded chip sockets
- Fitting a remote AA battery pack
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Two, Clay Harrell (pinrepair.com)