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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum (src_forum@alionscience.com )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Original Message:

Posted by: Eugene L. Neuliep (neuleip.eugene@orbital-lsg.com )
Organization:Orbital
Date posted: Tue Jul 6 14:52:00 US/Eastern 1999
Subject: Reuse of Removed Electronic Components
Message:
Is there any information about the reuse of Electronic components that have been removed from a CCA (Circuit Card Assembly)? Is it risky to reuse Diodes, Transistors, I.C.'s and etc. that have been put in backwards? Both those that have been powered up and those that have not been powered up. I need to know of any company policies and any industry standard recommendations. Thank you much, GeneN.


Reply:

Subject: Reuse of Electronic Components
Reply Posted by: Bruce Dudley (bdudley@alionscience.com )
Organization: Reliability Analysis Center
Date Posted: Tue Jul 13 13:57:01 US/Eastern 1999
Message:
Any semiconductor that has been installed improperly is subject to failures at pins that were not expected to see input power levels. The resulting condition could be degraded or shorted devices. Therefore, I would recommend the removal and discarding of these devices due to potential unreliability problems. The second problem is the reuse of properly installed devices. From the Clyde Coombs book "Printed Circuits Handbook" fourth edition,McGraw Hill 1996, rework including replacement of devices is considered to be a significant reliability problem. Some of the reasons cited are: Thermal Shock During Rework, Circuit Board Measling, Temperature and Humidity Stress Failures (Popcorn Effect), Package Cracking, Fatigue Cracks of Copper Barrels, Damage to Adjacent Components and Lower Quality Solder Operations. Another source of information on rework is the Proceedings of the 1st International Conference on Clean Electronic Products and Technology, October 1995, Page 214-217, "Chiprack -- A Novel Architecture to Facilitate Disassembly and Reuse of Electronic Components".


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