Fanuc LTD. TP11 drive is a servo‑drive controller used in CNC machining and industrial automation, typically paired with Fanuc spindle or motor units. Common failure modes for this class of drives include power supply degradation, overheating of the main I/O board, phase sensor faults, and firmware corruption that can trigger error codes such as “E5” or “E9”. First‑check diagnostics should verify the 48 V/24 V input rails are within spec, inspect all connectors for corrosion or loose contacts, and review the drive’s diagnostic display for recent fault logs. If power and wiring appear normal, perform a short‑circuit test on the output phase terminals and confirm firmware integrity via the serial console.[oss-gpt-20b]