The battery-backed 5101 RAM uses only data lines DB0 to DB3

Because the 5101 settings RAM (Z5) is a 4-bit part, it connects only to the low four data lines DB0-DB3. It draws very little power while its CE2 pin (pin 17) is held low, which is what lets the battery keep it alive.

Systems

• Gottlieb System 80
• Gottlieb System 80A

Related tips

• Test connector TC1 pins for the address and data bus
• System 80 control board chips
• Control board clock frequency
• Control board power-on checks
• How the 32 option switches are read
• Key pins on the System 80 LSI chips
• Check the RAM power-down protection
• Display data in attract mode

Source: System 80 Service Manual, Gottlieb