The Teijin‑Seiki ARN15‑A is an AC servo amplifier designed for use with AR series servo actuators in industrial equipment such as CNC machines and process controls. Common failure points for this class of drives include power supply degradation (over‑voltage, ripple), capacitor failure on the input stage, insulation breakdown between high‑current windings, and firmware or communication errors from the host sequencer. Initial checks should verify that the 48 V/AC mains is within spec and that all input/output connectors are clean and properly seated; inspect for obvious signs of overheating or component damage, then review any diagnostic error codes displayed on the drive’s panel or communicated via Modbus/IP.[oss-gpt-20b]