Pressing the play/test button does nothing.

The play-test button will not start the test sequence

Cause: An open slam switch, a closed tilt switch, a broken play/test switch or its wiring, a failed isolation diode for that switch on the bottom board, or the control board.

Checks

• Check the slam switch and tilt switches.
• Check the play/test switch for continuity when pressed.
• Test the play/test switch isolation diode on the bottom board.

Fix

• Repair the switch, wiring or diode; replace the control board only if those are good.

Systems

• Gottlieb System 80
• Gottlieb System 80A

Related tips

• One or more playfield switches do nothing
• Switch test (step 18) shows switches closed
• A coin chute switch does not register or registers wrongly
• A playfield switch triggers the wrong response
• The slam input has priority over every other switch
• How the switch matrix is scanned
• Where to see the switch matrix strobes
• The wrong sounds or tunes play

Source: System 80 Service Manual, Gottlieb