Key pins on the System 80 LSI chips

The appendix gives pinouts for the 6502 CPU, the 2332 ROM (4K x 8, both chip selects high to enable), the 7641 PROM (512 x 8, chip selects 1 and 2 low and 3 and 4 high to select), the 5101 RAM (256 x 4) and the 6532 RIOT. Use them with a logic probe to check chip selects and bus activity when a board will not boot.

Systems

• Gottlieb System 80
• Gottlieb System 80A

Related tips

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

Source: System 80 Service Manual, Gottlieb