| Symptom | Most likely causes | First checks |
|---|---|---|
| Feed inconsistency | Worn tip, liner drag, roll pressure error, spool drag | Remove tip and compare feed |
| Poor weld quality | Wrong polarity, wrong gas, dirty work, weak clamp | Confirm gas, polarity, and clamp |
| Feed but no arc | Loose output lugs, bad clamp path, burnt tip | Check lugs, clamp, and tip |
| Output worsens after several welds | Heated gun neck, cable lugs, feeder wear | Inspect hot components after load |