Board reference · WSM-315 HF
WSM-315 HF arc-start board reference
Use this page when a WSM-315 has gas but no HF, HF relay action but no start spark, HF present but no main arc, or HF that does not shut off after arc transfer. The HF board should be diagnosed together with the gas sequence, control-board command and current-feedback/cutoff logic.
HF arc-start sequence
Torch commandControl board receives trigger or pedal contactor request.
Gas opensSolenoid opens before or during HF start depending on timing.
HF enableControl board sends timed HF command to the arc-start board.
HF pulseRelay/transformer/discharge path creates high-voltage ignition.
Arc transferMain inverter current takes over after ignition.
HF cutoffFeedback/arc-detect signal releases HF after welding starts.
HF fault map
| Observation | Likely area | Next check |
|---|---|---|
| Gas opens, no HF relay | HF command from control board or relay coil supply | Check HF enable signal and relay coil voltage. |
| HF relay clicks, no spark | Relay contacts, HF transformer, discharge resistor, HV diode/silicon stack | Inspect primary-side transfer and visible HV component damage. |
| HF spark present, no main arc | Main output enable, work return, torch output path, feedback | Check OCV/output path and current-feedback logic. |
| HF stays on | Arc-detect/cutoff signal or relay release path | Check feedback signal and relay release after arc starts. |
| Intermittent HF | Dirty gap, weak transformer, cracked lead, loose HF cable | Inspect and service HF coupling path safely. |
Do not test HF board in isolation first
The HF board depends on control-board timing and must shut down after arc transfer. A board that produces HF on the bench may still fail in the machine if gas timing, torch return, feedback or cutoff logic is wrong.