Reboot the system to check if an external device was causing the freeze. 3. Inspect LED Status Indicators on the Main Board
You have just powered up your CNC machining center or industrial robot. The FANUC operator panel lights up. You expect to see the familiar position screen or the alarm history. Instead, a stark, white-on-blue (or black-on-amber) text message stares back at you:
Once you resolve the root cause—whether by replacing a module or clearing a corrupted SRAM—the CNC will typically boot into a clean state or throw severe system alarms because its custom parameters are missing. To bring the machine back to production:
Open the electrical cabinet and look at the back of the CNC control unit (usually a FANUC 0i, 16i, 18i, 21i, or 30i series). Inspect the status LEDs on the main board. Status LED Indicators fanuc starting system software please wait
Press and hold the two right-most softkeys (the keys under the screen) while turning the power ON.
Motherboard replacement required by a qualified repair facility. Preventative Maintenance Practices
Have you recently noticed any on the screen? Share public link Reboot the system to check if an external
If it stops on a specific letter or number (e.g., E , F , or 8 ), consult your specific FANUC Maintenance Manual index. This code indicates exactly which hardware initialization step failed (such as an axis card or memory sub-module). Step 5: Verify Voltages and Connections
Wait 3 to 5 minutes to allow all capacitors on the FANUC power supply and drives to fully discharge.
Check incoming 24VDC voltage; replace the control power supply module if voltage is low or unstable. The FANUC operator panel lights up
Once you are in the MAIN MENU of the Boot System, you have powerful options at your disposal, such as:
30 seconds to 2 minutes. Stuck Duration: If the message persists for more than 5–10 minutes without change, there is a hardware or software corruption issue.
Ensure the cooling fans are working and the cabinet seals prevent oil mist from coating the circuit boards.