FANUC CNC system repair and testing by REACO CNC technicians.

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Explore our collection of FANUC repair cases

FANUC CNC Repair Cases

Each case provides in-depth troubleshooting processes, root cause analysis, and repair solutions for common CNC system issues. Whether it’s a servo drive alarm, spindle fault, or PCB malfunction, our engineers document every step to help you understand and solve similar problems.
Troubleshooting Fanuc 401 Alarm (VRDY OFF): A Case Study
The 401 Alarm (VRDY OFF) is one of the most common issues encountered in Fanuc CNC systems. While it indicates that the "Servo Ready" signal is missing, the root cause can vary from internal module failures to external wiring issues. In this article, we analyze a specific case of a full-axis 401 alarm and provide a step-by-step resolution process. 1. Problem Description A production facility reported that upon releasing the Emergency Stop (E-Stop) on a specific machine, a 401 Alarm occurred across all axes (X, Y, Z, A, B). Symptom: The... Read more...
FANUC PS5523/5524 Alarm — Cause and Solution
Alarm Overview PS5523: When the FANUC system displays the alarm “PS5523 WAITING THE OPTION CERTIFICATION", it indicates that the CNC system is currently waiting for option authorization. PS5524: The Alarm "PS5524 CERTIFICATION EXPIRE" indicates that the certification period for the system’s option parameters has expired. Once the alarm changes from “PS5523 WAITING THE OPTION” to “PS5524 CERTIFICATION EXPIRE,” it means the 30-day grace period has ended. This alarm typically occurs when: The OPRM_INF function file inside the FROM memory has been overwritten or deleted (for example, after system all files... Read more...

REACO CNC Expert Tip

Always document the alarm code and machine status before power cycling the CNC system. This helps pinpoint the root cause faster during troubleshooting.

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