Replace the decoupling capacitors on the CPU and driver boards
The electrolytics are probably dried out by now. Replace C1 on both the CPU and driver boards (power decoupling) and C36 on the CPU board (the power-on delay).
Systems
Related tips
- Which System 80 CPU board goes with which games
- System 80 CPU board main chips
- System 80 and 80A CPU boards swap only with the matching U2/U3
- Reading the System 80 CPU DIP switches
- U2/U3 rules ROMs decide which system a CPU board runs
- System 80 CPU board revisions D102, D107 and D20869
- Converting a D102 CPU board to take a 2716 game ROM
- Swapping CPU boards between System 80, 80A and 80B
Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)