Case 1831 ยท Public preview
A Protective Coating Can Miss the High Points of a Porous Resistor
Assembled resistors were compared with unassembled controls to assess a special protective coating intended to resist moisture and contamination. The supplied parts measured near nominal resistance.
Resistance measurementAssembled-control comparisonOptical microscopySEM
What the evidence preview establishes
The coating was thin and nonuniform even on unassembled controls, tending to fill surface depressions while leaving high points exposed. The underlying resistor bodies were unusually porous. The evidence did not show that assembly created the coating condition or that a supplied resistor had already failed electrically.
Why this case matters
Compare suspect resistors with untouched controls before blaming assembly. A coating that pools in a porous substrate's valleys may leave peaks unprotected; address body texture as well as nominal coating thickness.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, 4 interpreted figures, alternative explanations, limitations, and practical application guidance.