This template is the reusable decision layer for future brand batches.
How to Use This Playbook
Use it after intake and first symptom routing, but before internal repair.
Move through the branch in order: setup correction, external proof, known-good substitution, then internal escalation.
Do not skip to board-level repair unless the external and accessory branches are already bounded cleanly.
Decision Rules
Complaint branch
Stop at setup or accessory correction when...
Swap known-good external parts when...
Internal repair is justified when...
Core rules
If one process is still healthy, prove that branch first before condemning the shared power source.
If the complaint follows one torch, gun, clamp, pedal, spool gun, or front-end stack, keep the diagnosis outside the machine until substitution proves otherwise.
If power-path quality changes the symptom, fix that branch before opening the machine.
Only escalate to internal repair when the baseline process, power source, and accessory path have all been proven or bounded.