Proto Trak M3 20320R Control Pendant is a handheld interface used with ProtoTRAK CNC controllers to display status and send commands to the machine. Common failure points in this class of pendants include damaged LCD or LED displays, broken touch/knob contacts, power supply voltage drops, and communication link failures (e.g., serial or Ethernet). For troubleshooting, first verify that the pendant receives proper 12 V DC from its power connector and check for any visible signs of burn or corrosion. Next, inspect the serial/Ethernet cable for continuity and correct pin‑out, then review any error codes or status lights on the controller to confirm communication integrity. Finally, perform a visual inspection of the LCD/LED panel and touch contacts for mechanical wear before proceeding with component replacement.[oss-gpt-20b]