Etasis EFRO‑250A is a 230 W external switching power supply rated 100–240 VAC input and 12 VDC output, commonly used as an auxiliary unit in industrial inverter or UPS systems. Typical failure modes include degraded capacitors or electrolytic leakage causing voltage ripple or overheating, blown fuses or shorted protection circuitry leading to no output, and fan motor failure resulting in thermal shutdowns. First‑check diagnostics: verify input mains voltage with a multimeter, measure the 12 VDC output under load, inspect for bulging or leaking capacitors and check the status of any internal fuses or resettable PTC devices; if available, review any error codes displayed on the host inverter’s diagnostic panel.[oss-gpt-20b]