I like those words used together; reliability and due diligence. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dwight Mattix Sent: Tuesday, November 29, 2005 12:27 PM To: [log in to unmask] Subject: Re: [TN] Humidity and enclosed RF board At 09:34 AM 11/29/2005, Eric CHRISTISON wrote: >Agree with Richard about the environment. Letting the enclosure breathe >is also a good plan; how many mobile phones fail due to humidity >related failures? The answer is a very large number -- if the pwb and assembly are not clean. In layman's terms think of it like the fire triangle -- remove one leg and the fire goes out. If you can't remove potential or humidity then ensure an ionic clean assembly and avoid surface finishes prone to dendretic grow (e.g. silver in carbon ink, traditional immersion tin finishes) and the electromigration problem should be thwarted. Back in the 90's I dealt w/ big electro-migration problems (talking massive recall) in wireless local loop phones. They weren't even mobile phones. In that case they were installed in a condensing residential/office environments (India in monsoon season). The root cause fix in that particular case was in the cleanliness of the bare pwb. To the original question: Test and verify. Do your reliability due diligence -- sacrifice some hardware to science. my $.02 dw --------------------------------------------------- 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 -----------------------------------------------------