RNC70H1963FS Resistor Failure

Gideon Analytical Laboratories received an RNC70H1963FS resistor for electronic failure analysis. A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits. They are typically constructed of metal wire or carbon and engineered to maintain a stable resistance value over a wide range of environmental conditions. Resistors are rated both in terms of their resistance (ohms) and their ability to dissipate heat energy (watts). The RNC70H1963FS resistor has an electrical resistance of 196 ohms, and his a power dissipation rating of 0.500 Watts. The goal was to find the cause of the RNC70H1963FS resistor.

Failure analysis was conducted. Electrical testing was conducted; the resistor tested open. The plastic was removed and it was tested open again. The resistor was a metal film resistor on an alumina shaft. Resistance readings tested open between two wounds of the shaft. No visible damage was evident; there was no heat damage or overpower evident within the shaft. The shaft was cross-sectioned. This revealed a spot where the metal had come off the shaft of alumina. There was no evidence of cracking on the surface of the shaft. However, after removing more of the alumina, a crack was revealed. Since this crack only appeared in this single section of the resistor, the shaft (most likely) received a surface impact causing internal stress. As heat developed with the dissipation of power, the crack propagated and broke the surface of the metal film causing the open.

Gideon Analytical Laboratories is a multi-service analytical laboratory that can help all companies in the electronics industry if they encounter problems. If you are having problems in design, manufacturing, or application in the field, call Gideon Analytical Laboratories. Imagine the time and money you can save knowing that your products are safe and reliable. Avoid embarrassment and litigation, ensure your peace of mind, and maximize your profits. Call Gideon Analytical Laboratories for all of your failure analysis needs.

black die and arrows show crack

black die and arrows show crack

cross section shows crack

cross section shows crack

Open between wounds 7 and 8

Open between wounds 7 and 8

larger view of crack

larger view of crack