Main chips on the CPU board

The CPU is a 65C02 at U1, clocked at 2 MHz from U18 into its pin 39. Two 6522AP VIA chips sit at U4 and U5. The board needs only +5 V DC, which arrives on connector P1.

Systems

• Gottlieb System 3

Related tips

• CPU board 26285 versus 26285-1
• Booting a CPU board on the bench
• Logic chips worth stocking
• Missing P6 or P7 header on the CPU board is normal
• CPU board LED never lights
• U11 must be a 74HC123AN
• Replace a failed 6116 RAM with a 6264
• Game stuck showing the last four high scores

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