Lincoln Electric Vantage 400 is an engine‑driven, multi‑process welder that uses Chopper Technology® for rapid DC arc control and offers both CC and CV modes. Common failure points on this model include the engine‑drive generator’s alternator output, the chopper controller board (often showing a “Chopper Fault” or “Control Board Failure” code), and the high‑current welding transformer windings due to heat cycling. First‑check diagnostics should verify that the engine is running at rated RPM and supplying correct voltage to the welder input, inspect the chopper controller for burnt components or loose connections, and review any error codes on the display while performing a visual inspection of wiring harnesses and transformer windings for signs of wear or damage.[oss-gpt-20b]