Supplies on the original System 80 sound board

The sound board needs +5 V (from the power supply, edge connector pin 5), +12 V (from the bottom board, edge pin 1) and -12 V, which it makes itself from AC with diodes CR1-CR4 and a 12 V zener (1N4742A).

Systems

• Gottlieb System 80

Related tips

• Fault-finding the original System 80 sound board
• The original sound board self-test only works with S1 and S2 set opposite
• Original sound board option switches S1 and S2
• Fitting the original sound board PROM
• No sound at all
• Distorted sound
• The wrong sounds or tunes play
• Original sound board connector A6-J1

Source: System 80 Service Manual, Gottlieb