Powering a System 1 CPU board on the bench

Steps

• Use a PC power supply; the board needs only +5 V and -12 V.
• At J1: pin 1 (bottom) unused, pin 2 -12 V, pins 3-4 ground, pins 5-6 +5 V.
• Or wire to the caps by J1: C16 top lead +5 V, C16 bottom lead ground, C17 bottom lead -12 V.

Systems

• Gottlieb System 1

Related tips

• Aftermarket System 1 CPU boards
• Spare chips for System 1 boards
• Bench test of coil buffers Z6 and Z7
• Check the TC3 jumper plug on the CPU board
• The six Rockwell "spider" chips on the CPU board
• CPU board clock check
• Testing CPU input buffers Z29 and Z27
• CPU address and data line check

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