Nikki‑Denso Actus NPSA‑202MU/NPSA‑202‑E1 is a high‑current AC servo drive designed for industrial motion control, featuring integrated power electronics and signal conditioning for motor feedback. Common failure modes in this class include capacitor degradation on the DC bus, winding insulation breakdown, overheating of the MOSFET array, and loss of communication with the host controller due to firmware or I/O faults. Initial diagnostics should verify that the supply voltage is within spec and that all phase currents are balanced; check for visible signs of thermal damage or blown components on the board, and review any error codes or status LEDs displayed by the drive. Finally, confirm proper grounding and inspect the input/output connections for continuity and correct polarity.[oss-gpt-20b]