Fault route
TIG Pre-Flow Works but HF Has No Welding Current Diagnostic
A TIG start-sequence route for gas and HF activity without main welding current.
Quick Answer
If pre-flow and HF work but no welding current follows, the gas/HF start layer is not the first suspect. Move to PWM/current permission, driver output, main transformer/output rectifier and feedback shutdown evidence.
Diagnostic path
Pre-flow OK → HF OK → PWM/current permission → driver stage → output transformer/rectifier → feedback/protection.
Evidence table
Gas + HF present: start support works. No current: check PWM/current command and shutdown/protection. Driver present but no output: output transformer/rectifier path. Current starts then stops: feedback/protection layer.