: In many cases, the "pulse miss" isn't a broken wire but physical interference. If a tool is unbalanced or motor bearings are worn, excessive vibration can shake the encoder's internal optics. This causes the read head to momentarily miss lines on the internal grating, triggering the alarm. A simple check is to feel the motor housing for unusual vibration while it's running. The Weakened Signal

Several factors can interrupt the encoder signal. Understanding these causes helps narrow down the troubleshooting process. 1. Faulty or Damaged Feedback Cable

Consult your machine builder’s manual for the specific parameter restore procedure if the data was lost. 3. When to Contact Support

If you have an identical working axis on the same machine (e.g., swapping X-axis and Y-axis parts), you can isolate the fault:

Liquid ingress (coolant) at the motor junction box has corroded the pins, spiking the electrical current.

FANUC Troubleshooting Manual – FANUC CNC FAQ - MRO Electric