The AMC/D2/B1/E3 is a CNC operator control pendant from NEE Controls Ltd., typically used to interface with industrial motion controllers and provide user input for machine operation. Common failure points on this class of pendants include burned or tripped power supply circuits, degraded I/O contacts (especially the button matrix), and firmware corruption that can prevent booting or correct communication with the host controller. Initial checks should verify the 24 V DC input voltage, inspect the PCB for burn marks or loose solder joints, and confirm that all user‑interface LEDs and buttons function; then review any error codes displayed on the pendant or transmitted to the host PLC to isolate firmware versus hardware faults.[oss-gpt-20b]