P40 No-HF Drill

Drill Goal

• teach the trainee to separate no-HF, HF-no-OCV, and air-no-cut complaints
• teach the correct move from measurement card to parts substitution to opening map

Starting Scenario

• Model: P40
• Complaint: no HF start and the operator also reports air flow but no clean cut
• Arrival condition: torch front-end wear is visible and the air source quality is unknown

Expected Document Sequence

1. P40 measurement card
2. P40 parts substitution card
3. P40 board opening map only if the complaint still stays machine-side

Success Criteria

• the trainee says the first proof step is fresh SG55 stack, clean clamp, dry air, and the correct OCV test point
• the trainee keeps no-HF, HF-no-OCV, and air-no-cut as separate branches
• the trainee does not open the machine before torch-stack and support-voltage proof are done

Common Misses

• blaming the HF board before proving the striker gap and front-end stack
• measuring OCV at the wrong point
• mixing torch-stack and control-branch symptoms into one vague plasma failure

Debrief

• The key lesson is that the 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.