Forum: Reliability & Maintainability Questions and Answers
Posted by: Ed Takacs (email@example.com )
Date posted: Mon Nov 19 18:45:49 US/Eastern 2001
Subject: Power GaAs FET and LDMOS FET failure rate prediction
I am trying to determine the part reliability rate for LDMOS FETs-operating at L band and 60 Watts per FET (Tchannel<125°C)and Power GaAs FETs (operating about 4 Watts) with Tchannel also < 125 °C. MIL 217F calculates failure rates much higher than expected-(ie way out, unrealistic) I am looking for guidance-either a study, or manufacturers ap note or anything else- to determine a realistic part failure rate for the LDMOS and Power GaAs FET's. Thanks in advance for your help.
Posted by: Jeff Jackson (jackson14789 )
Date posted: Tue Nov 13 22:40:43 US/Eastern 2001
Subject: MIL-STD-471, Test Method 9, 30 Task Minimum????
I have studied MIL-STD-471A, Notice 2, "Maintainability Demonstration," Test Method 9, and want to know if anyone knows why the minimum sample size is 30 maintenance actions. Test Method 9 indicates that the procedure is based on the Central Limit Theorem. Appendix A of the document indicates that the sample of maintenance tasks must be at least four times the number of tasks for the selected test. So, the question is: Is the 30 task minimum somehow determined using the Central Limit Theorem, and if so, how?
Posted by: Sil Veldman (firstname.lastname@example.org )
Organization:Student University of Bradford
Date posted: Tue Nov 13 3:00:31 US/Eastern 2001
Subject: Spare parts control
Does anybody help me to find recent literature about spare parts controle combined with a risk analyse.
My dissertation is about this subject. Also how much spare must be stock, how can this be calculated. Thanks very much
Posted by: Ken Meyerhoffer
Date posted: Thu Nov 8 10:04:03 US/Eastern 2001
Subject: Prism BOM Import
The RAC Internet Home Page is saying 'PRISM Version 1.3 is here! Import your Bill of Materials into PRISM' We have Prism 1.3 and would like to know how to import a Bill of Materials. Importing a component library is not the same as importing a Bill of Material I.e System Tree. Thanks.
Posted by: Barry Moon (email@example.com )
Date posted: Thu Nov 8 7:28:09 US/Eastern 2001
Subject: Reliability degradation due to static damage
Does any data exist which may indicate the degree of that may occur when electronic components are exposed to static damage i.e. the reliability is typically reduced by 50%.