Buffer chips protect the control board LSI parts
Apart from the CPU, ROMs, RAM and RIOTs, the rest of the control board is ordinary TTL and CMOS buffering between those parts and the game wiring. A fault out in the game usually takes out one of these cheap buffer chips rather than an LSI part, so check the buffers first.
Systems
Related tips
- System 80 control board chips
- Key pins on the System 80 LSI chips
- Control board clock frequency
- Control board power-on checks
- Test connector TC1 pins for the address and data bus
- How the 32 option switches are read
- How the control board reset circuit works
- How the control board drives the displays
Source: System 80 Service Manual, Gottlieb