Ground fix: tie each ground plug's wires together
Steps
- Keep the original A18 plugs.
- On each of the four ground plugs, join all its ground wires together and solder them.
- Now any one good pin still grounds the whole bundle to the frame. Optionally link the four bundles too.
Systems
Related tips
- Erratic faults from a poor ground at the A18 board
- A2 and A3 plug wire colours
- A1 CPU board plug wire colours
- A5, A6, A8 and A20 plug identification
- Reading Gottlieb's striped wires
- Gottlieb wire colour number code
Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)