System 80 control board chips

The control board runs on a 6502 microprocessor (U1) from a single 5 V supply. Three 6532 RIOT chips (U4, U5, U6) handle all inputs and outputs and each holds 128 bytes of RAM. Two 4K x 8 ROMs (U2, U3) hold the system code, a 5101 CMOS RAM (Z5, 256 x 4) keeps the settings and totals when the game is off, and the game program is on 512 x 8 PROMs that change from game to game.

Systems

• Gottlieb System 80
• Gottlieb System 80A

Related tips

• Key pins on the System 80 LSI chips
• Buffer chips protect the control board LSI parts
• Control board clock frequency
• Control board power-on checks
• What each System 80 board does
• The battery-backed 5101 RAM uses only data lines DB0 to DB3
• Test connector TC1 pins for the address and data bus
• How the 32 option switches are read

Source: System 80 Service Manual, Gottlieb