- Wrong kind of tinning? - 5 Updates
- Fender vibro champ XD, PR736 of 2010 PbF - 1 Update
| N_Cook <diverse@tcp.co.uk>: Dec 01 02:00PM Pure tin tinning on a component which should have had derogated Pb/Sn tinning? The normal RoHS cheap component getting into the premium priced aerospace/military/medical traditional-solder product stream? "The problem was related to a cracked solder joint caused by exposure to extreme temperatures." http://www.theguardian.com/world/2015/dec/01/airasia-crew-actions-caused-jet-to-lose-control-say-crash-investigators |
| N_Cook <diverse@tcp.co.uk>: Dec 01 02:23PM On 01/12/2015 14:00, N_Cook wrote: > "The problem was related to a cracked solder joint caused by exposure to > extreme temperatures." > http://www.theguardian.com/world/2015/dec/01/airasia-crew-actions-caused-jet-to-lose-control-say-crash-investigators technical report on http://aviation-safety.net/ I've only keyword searched (solder,sn,pb) but amazingly I find no reference to chemical testing of the solder or what type of solder in the product manifests. |
| "pfjw@aol.com" <pfjw@aol.com>: Dec 01 07:22AM -0800 On Tuesday, December 1, 2015 at 9:23:11 AM UTC-5, N_Cook wrote: > On 01/12/2015 14:00, N_Cook wrote: > > Pure tin tinning on a component which should have had derogated Pb/Sn If I were to render an opinion, pure tin as a mechanical joint is a very bad idea, nor would I think that a sophisticated manufacturer would do that as a matter of intent. Pure tin is extremely brittle, and should NEVER be depended upon in any sort of situation where mechanical stresses (expansion/contraction/flexing) will take place. Add to this the whole issue of tin whiskers (which NASA, at least now understands all too painfully). If what you suggest is accurate, this is a design flaw of significant magnitude. If it is present fleet-wide, it is time to ground these beasts until the problem is addressed specifically. I would hope that aircraft manufacturers by now would have learned that some admixture to their solders is a necessary step to reliability. And would have learned by now from the Nuclear industry if not NASA that relying on pure tin is a dangerous practice. All-and-at-the-same-time, counterfeit parts are getting into the OEM repair stream at every level. It would not be difficult to believe where such parts may get into the OEM first-install stream as well. Peter Wieck Melrose Park, PA |
| N_Cook <diverse@tcp.co.uk>: Dec 01 03:28PM > All-and-at-the-same-time, counterfeit parts are getting into the OEM repair stream at every level. It would not be difficult to believe where such parts may get into the OEM first-install stream as well. > Peter Wieck > Melrose Park, PA I know from someone in the medical electronics field, that is extremely difficult , if not impossible, to guarantee that PbF components do not get into the derogated product stream, without sample chemical testing of each batch of componnts, done themselves. The supposed accredited documentation is easily compromised and cannot be relied on. With all the extra markup on derogated components, plenty of motive. |
| "pfjw@aol.com" <pfjw@aol.com>: Dec 01 08:27AM -0800 On Tuesday, December 1, 2015 at 10:28:49 AM UTC-5, N_Cook wrote: > of each batch of componnts, done themselves. The supposed accredited > documentation is easily compromised and cannot be relied on. With all > the extra markup on derogated components, plenty of motive. There are multiple exemptions for medical and certain industrial devices through 2019. Peter Wieck Melrose Park, PA |
| N_Cook <diverse@tcp.co.uk>: Dec 01 09:44AM Cut the cable ties to get the pcbs out. Then noticed one of the ac HT wires loose. It looks as though the blade may have been between shoe of crimp and the plastic cover, needed much more than finger pressure to slide the crimp over the terminal. Power fading up and down i could see that causing, will try simulating to see if a possible source of crackle when I power up with boards out of chassis. The pots are "digital" fashion. I was hoping the amp could be used without the DSP board connected as owner only ever uses clean, will check for that as well. Then try hot air and attack boards with nylon tipped engraver tool (headphone monitoring), to see if that divines any failed pbf joints, nothing suspect seen visually, plus ca change. Then a matter of resoldering the usual suspects and keep fingers crossed. |
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