Self test mode is only activated after a reset (tilt) or on powerup. It can be activated from either the dip switches or the edge connector. There are 11 different self tests. The credit (service) button must be pressed to advance to the next test.
  1. MAPPING OK or (incorrect address bit)
  2. RAM TEST OK or (chip location, eg. 1L, 3H)
  3. MIX TEST (if error, one or more characters will be out of sync)
  4. FORGROUND CHARACTER DISPLAY (screen is filled with different parts of foreground objects, if error has occurred, pictures will be distorted)
  6. SOUND (plays 16 different sounds. First 3 sounds are handled by chip XXX PSG1, remaining 13 sounds are handled by chip YYY PSG2).
  7. ROM TEST OK or (incorrect chip location, eg. 4D, 5B)
  8. SW TEST (activate all of the games switches. If good they will light as a solid square).
  9. DIP TEST. Shows status of dip switches. Note that test mode switches are also wired to edge connector in parallel.
  10. BACKGROUND CHARACTER DISPLAY. Shows all background maze configurations. Note video sync is temporarily lost between mazes causing them to scroll trough the mazes. This is normal).
  11. TILT TEST. Activate tilt switch, should reset card and repeat test mode.