System 1 switch matrix layout

Five strobes (0-4) and eight returns (0-7) give 40 switches, numbered 00-04, 10-14 and so on up to 70-74. On every game 00 is the test button, 01 and 02 the coin chutes, 03 the credit button and 04 tilt.

Systems

• Gottlieb System 1

Related tips

• Logic-probing the switch matrix
• Test PROM switch actions
• Testing switch return buffers Z9 and Z28
• Switch matrix dead after coil or GI voltage touched it
• Switch strobes missing at Z8
• CPU plug A1J7 (playfield switches) pins
• CPU plug A1J6 (coin door) pins
• Clamp diode mod to protect U5

Source: Gottlieb System 1 Pinball Repair from 1977 to 1980, Clay Harrell (pinrepair.com)