P40 Parts Substitution Card

This is the quick external-parts substitution card for the highest-value P40 torch-stack and air-path splits.

Use This Card When

Complaint branch	Swap first	If the complaint follows the part...	If the complaint stays with the machine...
no HF or weak HF	fresh `SG55` front-end stack and corrected striker gap	keep diagnosis in the torch-start branch	move to `24 V` support and control logic only if the complaint remains
air but no cut or transfer	known-good clamp and fresh torch stack	keep diagnosis in clamp or torch-stack branch	move into machine-side OCV and control branches
poor cut quality	fresh `1.0 mm` tip, electrode, nozzle with groove, and verified torch order	keep diagnosis in the consumable and torch-order branch	move deeper only if cut quality stays poor with a correct stack
air-path suspicion	known-good dry air path, about `65 psi / 4.5 bar` under flow, and cleared gas orifice	keep diagnosis in the air branch	move into electronics only after dry air is proven
starts are inconsistent after warm compressor cycles	known-good dry air path and purge-style contamination check at about `1/8 in / 3 mm` from clean metal	keep diagnosis in wet-air or contamination branch	move into electronics only if the gas stream stays clean

Stop if a fresh torch stack or clean clamp restores normal cut behavior.
Stop if pressure under flow is not staying around 65 psi / 4.5 bar.
Stop if the complaint disappears once the gas orifice and air path are corrected.
Stop if the purge-style contamination check shows oil or moisture in the gas stream.
Stop using the card and open the full guide if HF, OCV, and cut-quality symptoms still stay with the machine after the external stack is proven.