| Symptom | Most likely causes | First checks |
|---|---|---|
| Wire feeds but no arc | Bad clamp, loose front connector, worn tip | Inspect clamp, Euro connector, and tip |
| Spool gun works poorly | Gun setup, drive path, wrong mode | Verify gun mode and connector seating |
| Porosity / harsh arc | Gas leak, wrong polarity, nozzle/diffuser issue | Check flow, polarity, and front end |
| Thermal / fault behavior | Airflow restriction, duty-cycle overrun, internal fault | Check fan and recent weld load |