The solenoid driver board also carries the 190 V display supply
The same board regulates the low voltages and makes about 190 V DC for the display drivers, so treat it as a high-voltage board when it is powered.
The solenoid driver / regulator board makes about 190 V DC for the score displays (around 230 V on some Stern boards); a shock from it hurts. Work with the game unplugged and let the filter capacitors discharge, and use one hand and insulated probes for live checks.
Systems
Related tips
- Where the display high voltage enters and leaves the solenoid driver board
- Rebuild the solenoid driver board high-voltage section
- No score displays light at all
- Set the display high voltage to about 170 V
- First checks before repairing Bally score displays
- Capacitor C26 holds the display high voltage after power-off
- High voltage still too high or too low after a rebuild
- All score displays blank with the MPU fully booting
Source: Repairing Bally Electronic Pinball Games from 1977 to 1985, Part Three, Clay Harrell (pinrepair.com)