After fitting a new replacement power supply and repinning its connectors, the game boots but every score display stays off; the display high-voltage test point reads nothing.

All displays dark after fitting a new power supply: blown solenoid driver board fuse

Cause: A blown fuse on the solenoid driver board, which also carries the display high-voltage regulator.

Checks

• Measure the display high voltage at the regulator test point; no voltage there points at the supply side.
• Check the AC from the transformer arrives at the new supply's display HV terminals, and that every wire went to the right terminal.
• Check every fuse on the solenoid driver board as well as the power supply.

Fix

• Replace the blown fuse with the correct value.

The display supply runs at about 190 V DC. Power off before touching the regulator board or display connectors.

Systems

• Stern MPU-100

Games

• Stars

Related tips

• Where the display high voltage enters and leaves the solenoid driver board
• Rebuild the solenoid driver board high-voltage section
• Capacitor C26 holds the display high voltage after power-off
• No score displays light at all
• Set the display high voltage to about 170 V
• Power up and set a rebuilt high-voltage section
• All score displays blank with the MPU fully booting
• First checks before repairing Bally score displays

Source: Pinball Repair help group!! (Facebook group)