Case 2048 ยท Public preview
Coating Voids Can Create a Moisture Path to a Resistor Film
A metal-film resistor measured greater than 300 megohms and was electrically open.
Resistance measurementOptical microscopyMicrosectioningSEMEDSCoating-layer examination
What the evidence preview establishes
Corrosion of the nichrome resistance film was the most likely cause of the open circuit. Systemic voids in the lacquer body near the end caps created moisture-ingress paths to the extremely thin functional film.
Why this case matters
A cosmetic outer coating can conceal a connected internal defect. Evaluate every coating layer near resistor end caps because voids formed before final overcoating can sharply reduce corrosion life even when the exterior appears intact.
Full evidence reserved for MEMBER and STOREThe complete case includes the evidence sequence, four interpreted figures, alternative explanations, limitations, and practical application guidance.