Is the solder ROHS compliant Pb-free and if so could this be related to the joint crack? On Tue, Dec 1, 2015 at 3:22 PM, Upton, Shawn <[log in to unmask]> wrote: > I'm curious about the solderjoint itself. Looks like poor wetting, but it > looks like what they show as cracking looks more like a lifted land. Also, > what is the discoloration on the green trace running away from the land? > Reminds me of a board that I saw where the copper was damaged by battery > acid. Is that just an artifact from the conformal coating being removed > during inspection? > > The more I look at it, the more it looks like the crack goes all the way > around the joint though, can see a faint line most of the way down the > fillet. > > The DB-looking connector is corroded, but across from that it looks like a > transformer got attacked by the seawater also--so not fully conformally > coated? I could see wear and tear on the DB, but I would have thought the > whole board would be conformally coated. Speaking of which, I wonder if > that is where the cracks live, under that transformer-looking thing. All > the other components look like they would have "give" for thermal > expansion/contraction. Well, maybe not the TO cans I guess, but the photo > makes it look like that particular crack was relatively away from > everything else. But if the iron core was being attacked by seawater, > well, maybe that is where the rust color on the cracked solderjoint is from. > > That, or maybe it's under the relay--the lead itself is very rounded, > making think it's a relay pin. Which would sit flush on the board, and > perhaps yank. Certainly "clicks" on accuation. But then the rust would > come from...? the iron core inside the relay? > > Anyhow, I looked through the report, and while it's huge it appears it is > the typical cascade of failures--not one thing but rather several things > went wrong, each compounding the prior. > > Shawn Upton > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory > Sent: Tuesday, December 01, 2015 3:15 PM > To: [log in to unmask] > Subject: Re: [TN] Airbus crash pinned (in part) on solder joint failures > > I did a little more digging on the Esterline web page and looked at the > photo a little closer, and that relay doesn't fall into the ones that have > the space restrictions. This is the relay that is on that board: > > http://us.leachint.fr/aerospace/f250/ > > Steve > > On Tue, Dec 1, 2015 at 12:41 PM, Steve Gregory <[log in to unmask]> wrote: > > > There is something that I noticed on the photo of the electronic module. > > The board on the left that has the four Leach relays looks like there > > was a violation of a documented recommendation by Leach of the > > positioning of the relays next to each other. The document states that > > the permanent magnet inside the relay could affect the performance of > > another relay next to it if it is oriented in the same direction and not > separated by at least 1/8": > > > > http://www.leachintl2.com/english/english1/vol0/properties/N023eng.htm > > > > It looks to me like all four are oriented the same way and looks to me > > like they're closer than 1/8" = .125" = 3.175mm to each other. What do > > you think? > > > > Steve > > > > On Tue, Dec 1, 2015 at 11:37 AM, Stadem, Richard D. < > > [log in to unmask]> wrote: > > > >> Agreed. There was no redundancy here, nor was there an effective > >> default condition. > >> > >> -----Original Message----- > >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Ahne Oosterhof > >> Sent: Tuesday, December 01, 2015 11:35 AM > >> To: [log in to unmask] > >> Subject: Re: [TN] Airbus crash pinned (in part) on solder joint > >> failures > >> > >> Figure 35: Electronic Module of RTLU > >> > >> Not much of a failure to cause the loss of life and an aircraft! > >> > >> Conclusion: End-use of a board module dictates extreme level of > >> attention to design and testing protocols. > >> > >> Ahne. > >> > >> -----Original Message----- > >> From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Buetow > >> Sent: Tuesday, December 1, 2015 6:28 AM > >> To: [log in to unmask] > >> Subject: [TN] Airbus crash pinned (in part) on solder joint failures > >> > >> Here's the report: > >> http://kemhubri.dephub.go.id/knkt/ntsc_home/ntsc.htm > >> > >> > >> > >> Discussion of the electrical short and cracked solder joint begins on > >> page 104. > >> > >> > >> > >> > >> > >> Best, > >> > >> > >> > >> Mike > >> > >> > >> > >> Mike Buetow > >> > >> PCD&F/Circuits Assembly > >> > >> w/m: 617-327-4702 > >> > >> @mikebuetow > >> > >> > >> > >> The 2015 CIRCUITS ASSEMBLY *Directory of EMS Companies:* > >> circuitsassembly.com/dems > >> > >> > >> _____________________________________________________________________ > >> _ This email has been scanned by the Symantec Email Security.cloud > >> service. > >> For more information please contact helpdesk at x2960 or > >> [log in to unmask] > >> _____________________________________________________________________ > >> _ > >> > >> _____________________________________________________________________ > >> _ This email has been scanned by the Symantec Email Security.cloud > >> service. > >> For more information please contact helpdesk at x2960 or > >> [log in to unmask] > >> _____________________________________________________________________ > >> _ > >> > >> _____________________________________________________________________ > >> _ This email has been scanned by the Symantec Email Security.cloud > >> service. > >> For more information please contact helpdesk at x2960 or > >> [log in to unmask] > >> _____________________________________________________________________ > >> _ > >> > > > > > > -- > > > This email and any attachments are only for use by the intended > recipient(s) and may contain legally privileged, confidential, proprietary > or otherwise private information. 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