Use heavy wire for the optional driver board ground jumpers
The optional driver board ground work can carry up to about 8 A, and 30-gauge wire-wrap wire burns through at about 3 A. Use clipped resistor leads or similar heavy wire, or double or triple any wire-wrap. Skip the optional work if you are new to board repair; the mandatory cabinet ground steps matter far more.
Systems
Related tips
- Optional ground mod steps 2 to 9: driver board ground jumpers
- Ground mod step 5: direct ground wire to the driver board
- Test the driver transistors while the board is out for the ground mod
- Test driver board outputs by grounding transistor tabs
- Optional ground mod steps 10 to 12: cut the Q64 loop trace and tidy up
- Drop bank reset coil dead everywhere: driver ground wire moved to the wrong J4 pin
- Diode-test a driver board 2N6043
- Diode-test a driver board 2N3055
Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)