One score display works perfectly in the display test, but is completely blank in attract mode and during games. Its high voltage is present, and the display works in other positions.

Player 2 display works in display test but goes blank in play: broken latch strobe wire

Cause: The latch strobe wire to pin 15 of that display's connector was broken inside its insulation, part-way along the wire.

Checks

• Swap the display into another position to confirm the display itself is good.
• Check continuity of each wire to that display's connector end to end while flexing the harness, especially the latch strobe line.

Fix

• Repair or replace the broken latch strobe wire.

Systems

• Bally MPU AS-2518-17

Games

• Eight Ball

Related tips

• One or two score displays completely blank
• A display not working from MPU or sound board faults
• F2 blown, no display high voltage at TP2
• Displays strobe on early Bally SS: check the J3 ground pin for the HV circuit
• Set the display high voltage to about 170 V
• Score display digit parts by position
• Capacitor C26 holds the display high voltage after power-off
• Only even-numbered score displays show numbers

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