Ground mod for the System 80B power supply
Steps
- Reflow the .156" header pins of J1 and J2 on the 80B power supply; cracked joints here are very common.
- Solder a wire to J1 pins 1 and 2 and take it to the bolt on the yellow-covered ground plane, lower right in the backbox.
- Also (step 8) take the white ground wire out of J1 pin 2 in the bottom plug, crimp it into a new Trifurcon pin together with a second wire, and run that wire to the ground plane screw at the upper right of the backbox.
Systems
Related tips
- While the 80B power supply is out
- Which System 80 power supply boards are interchangeable
- Ground mod step 1: CPU board ground wire
- First power-up, step 3: run the power supply on its own
- System 80B +5 V drifts or jumps
- Set the 80B +5 V after replacing the trim pot
- Ground mod step 2: repin the power supply to CPU power cable
- Replacing the 80B power supply with a switching supply
Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)