Fault route
CT-312 Gas Clicks No HF No Arc Diagnostic
A CT-312 TIG/plasma support-path route for gas action without high-frequency start or arc transfer.
Quick Answer
Gas action proves the trigger/gas support path is partly alive, but it does not prove HF command, PWM permission or output drive. Check bottom-board gas/HF socket support, mode switch, HF command and main output transfer before replacing the inverter board.
Diagnostic path
Torch input → gas valve click → HF command → HF board output → main output / work-return transfer.
Evidence table
Gas valve clicks: gas path partly works. No HF command: mode/timing/control path. HF command but no HF: HF board or HV path. HF present but no arc: output, torch or work return.