One or more segments, or whole digits, stay lit or never light.
A display segment or digit is always on or always off
Cause: A faulty display board if only one display is affected; a wiring fault, a display board loading the shared lines, or the control board if several are affected.
Checks
- If only one display shows it, that display board is the fault.
- If several show it, check the wiring between the displays and the control board.
- Unplug the display boards one at a time (power off each time); if the fault disappears from the others, the board just removed is loading the lines.
Fix
- Replace or repair the faulty display board.
- If no display board is to blame, repair or replace the control board.
Switch the game off before unplugging any board connector. The display supply carries 60 V DC (and 42 V DC); keep fingers off the power supply and display boards while the game is on.
Systems
Related tips
- How the System 80 fluorescent displays light
- Telling a bad display driver from a bad display tube
- Seven-digit display board (A14) parts
- Score displays are off but the status display works
- Status display is off but the score displays work
- The display voltages to check
- How the control board drives the displays
- How the Gottlieb fluorescent displays work
Source: System 80 Service Manual, Gottlieb