| Symptom | Most likely causes | First checks |
|---|---|---|
| Feed rough or slipping | Liner drag, bad tip, wrong roll pressure, spool drag | Remove tip and compare feed |
| Arc poor or spattery | Wrong polarity, poor gas, dirty work | Confirm polarity, gas, and clean base metal |
| Feed but no weld | Loose lugs, weak clamp, burnt tip | Check clamp, lugs, and tip |
| Degrades when hot | Heated consumables, output lugs, or gun neck | Inspect immediately after sustained welding |