Confirm whether main current has actually started.
Fault route
TIG HF Stuck On After Arc Start Diagnostic
A TIG HF cutoff route for machines where high-frequency start does not stop after arc transfer.
Quick Answer
HF should be active only during arc start. If high frequency remains after arc transfer, treat it as an HF cutoff/control fault rather than a normal arc-start condition.
- First confirm that main current has actually transferred; otherwise HF may still be trying to start the arc.
- If main current is flowing but HF remains active, inspect HF relay/control output and arc-transfer cutoff evidence.
- A stuck HF relay/contact can continue HF even when control command has ended.
TIG HF stuck-on route
Separate failed arc transfer from failed HF cutoff.
Control command should end after transfer.
Relay/contact can stick even if command ends.
Arc-transfer or feedback signal may fail to stop HF.
Repair HF board after command/contact evidence.
HF stuck-on evidence table
| Evidence | If observed | Repair direction |
|---|---|---|
| No main arc transfer | HF may continue because arc has not transferred. | Diagnose main output, torch/work return, gas and consumables. |
| Main current flows but HF command remains | Control-board cutoff/timing problem. | Inspect control board and arc-transfer feedback. |
| HF command ends but HF continues | HF relay/contact or HF board stuck. | Repair HF board relay/output path. |
| Feedback/cutoff signal missing | Control does not know arc transferred. | Check feedback/cutoff path. |
Related records
Use these based on whether command or HF hardware is stuck.