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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: Jon Hisey (jon.hisey@psion.com )
Organization:Psion Teklogix
Date posted: Wed May 16 14:35:34 US/Eastern 2001
Subject: Headset MTBF
Message:
I am looking for any information illustrating the calculation of MTBF for a headphone / microphone assembly. Or how others are classifying these devices according to Mil HDBK 217 F


Reply:

Subject: Microphone/Headset Reliability
Reply Posted by: Bruce Dudley (bdudley@alionscience.com )
Organization: Reliability Analysis Center
Date Posted: Mon Jun 4 12:15:25 US/Eastern 2001
Message:
MIL-HDBK-217F, Military Handbook, Reliability Predictions of Electronic Equipment has failure models for most commonly used electronic and elctromechanical components. Headphones and microphones are not included in the MIL-HDBK 217 component list. Therefore, to predict the expected mean-time-between-failure (MTBF) for microphones requires the application of other sources of data. In this case, the Non-Electronic Parts Reliability Data (NPRD-95) book, which is available from the RAC product catalog, has information related to dynamic microphones. The failure data collected on this item is from commercial components in a ground benign condition. That is, operation is in a controlled environment such as, an office or laboratory. The NPRD data shown is from one source and is: zero failures in 1.88 million hours. This translates to a MTBF of approximately 1.88 million hours, assuming a failure for estimating purposes. Other analyst would uses this values in the system prediction if the conditions are benign. If the conditions are not benign then a translation of the microphone MTBF would be required. Translation factors are presented in the Reliability Toolkit, Commercial Practices Edition and allow the analyst to predict at various operating conditions.


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