Case 212 ยท Public preview
Mounting-Hardware Interference Can Crack Internal PWB Traces
Two internal signal traces became open after shock testing and changed between open and closed when nearby mounting pressure was adjusted.
Continuity isolationControlled excavationSequential microsectioningOptical microscopySEMFracture-path correlation
What the evidence preview establishes
Oversized connector-retainer washers interfered with the mounting frame and bent the PWB. Combined bending and shock stress produced a radial crack from a screw-hole wall through the upper laminate layers and both internal signal traces.
Why this case matters
Pressure-sensitive continuity is strong evidence of a mechanically active crack. Trace the circuit, section outward from nearby mounting features, and evaluate hardware clearance before attributing an intermittent open to PWB fabrication.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, four interpreted figures, alternative explanations, limitations, and practical application guidance.