A dot matrix display that looks fine elsewhere is dim, patchy or blank in a System 3 game.

Display works in a Williams game but not in System 3

Cause: System 3 drives the display at lower high-voltage levels, so an outgassed display shows its weakness much more.

Checks

• Confirm the A8 supply voltages are correct.

Fix

• Replace the display.

The A8 controller makes roughly +62 V, -100 V and -112 V for the display; keep hands off it with power on.

Systems

• Gottlieb System 3

Related tips

• Dot matrix dark: +62 V missing
• Display test shows errors and the DMD mini-game restarts the game: faulty DMD
• The A8 dot matrix controller board
• Garbage on the dot matrix at power-on
• Bottom two rows of the DMD dark: row pins broken off the glass, bridged to the traces

Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)