Failure Analysis of Variable Resister
Failure Analysis of Variable Resister
Wednesday, November 8, 2017
Summary:
We investigated failure-causes of three modules which were found by the routine inspection in high reliability equipments. As the results of the investigation, we estimated these failures were caused by different types of variable resisters(wire wound type, cermet type, carbon composition type). We report three failure analyses of variable resisters. (1) Wire wound type: The R13(resistance between #1 and #3 terminals) was broken by the scratch in manufacturing. (2) Cermet type: The wiper was unstable because the wiper-fixing was not enough in manufacturing. (3) Carbon composition type: The R12(resistance between #1 and #2 terminals) was unstable because of extraneous materials in manufacturing or the zinc-whisker.
We investigated failure-causes of three modules which were found by the routine inspection in high reliability equipments. As the results of the investigation, we estimated these failures were caused by different types of variable resisters(wire wound type, cermet type, carbon composition type). We report three failure analyses of variable resisters. (1) Wire wound type: The R13(resistance between #1 and #3 terminals) was broken by the scratch in manufacturing. (2) Cermet type: The wiper was unstable because the wiper-fixing was not enough in manufacturing. (3) Carbon composition type: The R12(resistance between #1 and #2 terminals) was unstable because of extraneous materials in manufacturing or the zinc-whisker.