Ingemar, This topic can get very deep very quickly so I'll keep my comments general. We do employ HALT/HASS here at this company. Yes, it does increase MTBF drastically along with early identification of any process or design issues. Yes, you can apply the HALT/HASS methodology to specific functions or reduced areas. You first need to identify the operational purpose of the suspect product then research proper methods for stress testing. Build a HALT/HASS profile for the low yield area of interest. Employ six sigma for statistical analysis and there ya have it. Some call the process black magic as there are so many variables involved and dialing-in to the right combination and level of stresses can be quite the challenge for an inexperienced HALT engineer. I can tell you from my experience that the HALT/HASS process has saved our company countless millons $$$ in field returns/repairs. A plus is name brand recognition=reliability over the years that HALT/HASS has been employed. Hope this helps. Accelerated Stress Testing Handbook: Guide for Achieving Quality Products H. Anthony Chan Halt, Hass, and Hasa Explained: Accelerated Reliability Techniques by Harry W. McLean Accelerated Reliability Engineering: HALT and HASS by Gregg K. Hobbs Barrie Fraley EMC Corp HWQA/Electrical DVT/HALT -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ingemar Hernefjord (KC/EMW) Sent: Tuesday, June 28, 2005 10:54 AM To: [log in to unmask] Subject: [TN] HALT&HASS&MTBF Anyone out there who use these and really got higher MTBF? And was it worth the cost? Not much discussed about in TN? Maybe wrong forum? Just in case someone was applying HALT&HASS. My very q is this: can you apply this on whole equipment, or just on single functions or reduced areas because of too many parameters? Cheers Ingemar Hernefjord Ericsson Microwave Systems --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------