P40 No-HF Instructor Guide

Drill

• P40 no-HF drill
• P40 no-HF answer key

Use This Guide For

• teaching plasma branch separation
• stopping the reflex to blame the HF board before torch stack and support-voltage proof

Opening Prompt

• "A P40 shows no HF and the operator also reports air flow but no clean cut. What do you prove before you open it?"

What To Listen For First

• the trainee should say fresh SG55 stack, clean clamp, dry air, and the correct OCV test point first
• they should keep no-HF, HF-no-OCV, and air-no-cut as separate branches

Redirect Questions

• if they rush into the HF board: "What does the front-end stack still have to prove?"
• if they mix branches together: "Which symptom is start, which is output, and which is cut quality?"

Strong Answer Markers

• they use the measurement card and parts substitution card before the opening map
• they identify the correct OCV test point as part of the proof
• they keep torch-stack, clamp, and air quality active until bounded

Common Failure Modes

• blaming the HF board before the striker gap or stack is proven
• measuring at the wrong point and creating a false no-OCV story
• treating all plasma complaints as one undifferentiated failure

Debrief Notes

• reinforce that torch stack and support rail explain more P40 complaints than the internal HF board does
• internal opening is justified only after torch stack, clamp, air, and support-voltage proof are already clean