Circuit reference

TIG HF Arc-Start Sequence Reference

A general TIG high-frequency arc-start sequence reference for WSM, WSE, CT-312 and similar machines.

General sequence

This page has a specific TIG HF role

This page explains the general TIG HF arc-start sequence. Use the relay/transformer/discharge page for component-level HF path evidence.

Related TIG HF start pages

TIG HF content is separated by user intent: broad fault entry, diagnostic route, general sequence, timing/cutoff subtopic, discharge-path circuit and component testing.

No high-frequency fault entryBroad symptom page for users starting with no HF start. HF weak or missing diagnosticStep-by-step route for gas but no HF, weak HF, stuck HF or no arc transfer. HF relay / transformer / discharge pathCircuit path for relay, transformer, discharge resistor, spark gap and HV diode evidence. 40V / 4s cutoff controlTiming/cutoff logic subtopic for HF start control. HF arc-start sequenceGeneral TIG HF start process page. HF component testingSpark gap, discharge resistor and HV diode checks after the path is isolated.

Quick Answer

The TIG HF arc-start sequence should be treated as a controlled event: torch input, gas pre-flow, HF command, HV generation, arc transfer and HF cutoff.

HF hardware is only one layer; missing control command can also create no-HF symptoms.
HF stuck on after arc transfer is a cutoff/control problem, not normal start behavior.
Use this reference as a neutral circuit path for WSM, WSE, CT-312 and similar TIG machines.

TIG HF sequence evidence

Sequence layer	Expected behavior	Failure pattern
Torch input	Starts the timing sequence.	No gas/HF/current if trigger input is missing.
Pre-flow gas	Gas opens before HF/current.	No gas or gas timing abnormal.
HF command	Control board commands HF only during start.	No HF if command missing; stuck HF if command does not end.
HV pack / relay	HF board generates start energy.	Command exists but no HF at torch.
Arc transfer	Main current takes over after arc starts.	HF may continue if transfer evidence missing.
HF cutoff	HF stops after transfer.	HF stuck on after arc start.

Related records

Use symptom pages after this sequence reference.

WSM-315 no HF arc startNo-HF symptom route.HF stuck on after arc startHF cutoff fault route.TIG timing routeFull gas/HF/current sequence.