Swap the three 6532 RIOT chips when a CPU board dies
The CPU board carries three 40-pin 6532 RIOT chips: U4 runs the switch matrix, U5 the displays and U6 the solenoids and lamps. When a board dies, swap them around; if the symptom changes, one of them is bad. They are often soldered in, so fit sockets whenever you replace them.
Systems
Related tips
- 6532 RIOT port pins on the System 80 CPU board
- System 80 CPU board main chips
- System 80 and 80A CPU boards swap only with the matching U2/U3
- Use exact chip types in the CPU clock circuit
- Which System 80 CPU board goes with which games
- Test EPROM stalls at the display or lamp/solenoid RIOT
- Replace the decoupling capacitors on the CPU and driver boards
- Reading the System 80 CPU DIP switches
Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part Two, Clay Harrell (pinrepair.com)