What is inside a Smart Switch

The drawing on page 57 shows the Smart Switch circuit: the piezo film feeds the gate of a small 2N7002 MosFET through a 100 meg resistor, with a second 100 meg resistor and a 100 pF capacitor to its source; the MosFET's drain is on the strobe (pin 1) and its source reaches the return (pin 2) through a DL4148 diode. Pin 2 is the end with the bracket on both the rollover and pop bumper versions.

Systems

• Gottlieb System 3

Related tips

• Gottlieb Smart Switches (piezo)
• Never bend a Smart Switch blade
• A failed Smart Switch can be replaced by a plain switch
• Switch diodes are on the A17 board, not the switches
• Catching random switch closures
• Proving the driver board's switch strobes
• Lamp and switch matrix size and drivers
• System 3 slam switch is normally open

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