Ground mod for the solenoid return at J3 pins 23-24
Run a short wire from driver J3 pins 23-24 to the board's ground foil to relieve those pins. Keep the 5 V ground (J3 pins 18-22) separate from the solenoid ground.
Systems
Related tips
- Adding a ground jumper at C23
- Solenoid driver/regulator board test point voltages
- Jumper TP1 to TP3 on the solenoid driver
- Solenoid driver/voltage regulator board test points
- Solenoid driver board: how the MPU selects a coil
- Skip the driver board mods on Baby Pac-Man
- Solenoid driver board: test points and regulators on the layout aid
- Burnt pins at solenoid driver J3
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part One, Clay Harrell (pinrepair.com)