No, Ioan, You can't create a resonance circuit that way. The method works with caps only. Cracked BGA solder joints...who/what is cracking them? Thought such problems were very rare nowadays, at least if you are still soldering with SnPb (our MIL production need not change to leadfree in 10 years). Inge -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Tempea, Ioan Sent: den 19 juni 2006 13:48 To: [log in to unmask] Subject: Re: [TN] Finding cracked capacitors Inge, this is very interesting! Would this equipment take care of the cracked BGA solder joints? Thanks, Ioan -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Ingemar Hernefjord (KC/EMW) Sent: Monday, June 19, 2006 5:58 AM To: [log in to unmask] Subject: Re: [TN] Finding cracked capacitors It may be a little late adding test methods, but I'm curious about what the reaction will be on my proposal. Years ago, Yves Ousten, Institute Polytechnic Paris, gathered a number of guys from the universities and the industry in order to find an acceptable way of finding defect ceramic capacitors. He based his method on resonance ciruitry, where any defect cap would deviate from a specified RF resonance signature. He utilized the generation of elastic waves and piezoelectric effects, microcracks having an essential influence on these parameters. He has written a lot about the test method, myself, I have just two reports: "Improving Reliability of electronic assemblies using early physical and electrical indicators." and "Non-destructive detection and localization of defects in multilayer ceramic capacitors using electromechanical resonances." "The use of Impedance Spectroscopy, SEM and SAM imaging for early detection of failures in SMT assemblies." It seems as the test method calls for skilled RF test engineer and quite a expensive RF equiment. On the other hand, both these are available at big companies. We were planning to use Ousten's method, but we have less need nowadays, as microcracks are rather rare. Anyone who have used this capacitor test method? 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 -----------------------------------------------------