But inside the main processor (the CPU) of every FANUC controller—whether it’s a Series 30i Model A CNC or an R-30iB Robot controller—there is a moment of panic during a cold start. The hardware is live, but the "brain" is empty. It doesn't know how to talk to the servo motors, it doesn’t know how to read the teach pendant, and it has no idea how to interpret G-code or TP programs.
: A faulty CPU board, SRAM card, or a dead CMOS/main board battery can cause a boot failure. Power Supply Issues fanuc starting system software please wait