Tin whiskers  (pics heavy) - Page 1
Forum section: electronics / general

author: flolic
author_rank: Frequent Contributor
timestamp: January 31, 2013, 07:03:38 pm
content: Yap, this sh*t is realToday I found one old power supply that I dig out of a dumpster 15 or so years ago. Since then, it was sitting forgotten in a open cardboard box collecting dust.From date code on chips, supply is from 1979.Upon closer look, I noticed something interesting on a trimpot...Power Mate CorpAnd damned whiskers

author: ve7xen
author_rank: Super Contributor
timestamp: January 31, 2013, 07:24:43 pm
content: This phenemon amazes me. Is the mechanism understood?Also you didn't say - does the supply still work?

author: JuiceKing
author_rank: Regular Contributor
timestamp: January 31, 2013, 07:34:18 pm
content: Wow, that's severe. Tin whiskers are a serious problem.Check out this extremely cool video.

author: jnd
author_rank: Regular Contributor
timestamp: January 31, 2013, 07:37:11 pm
content: I wonder if this will cause more problems in the future as pure tin finish is common nowadays.

author: jahonen
author_rank: Super Contributor
timestamp: January 31, 2013, 07:44:00 pm
content: Exact mechanism of whisker growth is still not known. Not even factors which influence it, I believe that various studies have shown contradicting results. Electroplated tin is one of metal surfaces which have strong tendency to produce whiskers. Only thing which seems to be pretty constant is the thickness of a whisker, it lies between 1-10 µm. A whisker can grow instantly or after several years. Few percent of lead suppresses whisker growth completely.NASA has a excellent page on whiskers (and other unrelated problems that RoHS has created):http://nepp.nasa.gov/whisker/Regards,Janne

author: saturation
author_rank: Super Contributor
timestamp: January 31, 2013, 08:13:29 pm
content: Very nice clear photos. Most impressive is you noticed it with your unaided eyes.

author: flolic
author_rank: Frequent Contributor
timestamp: January 31, 2013, 08:19:57 pm
content: Thanks. My Canon 450D and 100mm f2.8 macro lens are great combination for this kind of pictures.I noticed sparkling under the bright light. Upon closer inspection it become obvious what's going on, you can see "hairs" with your naked eye. If you have good vision, off course.Quote from: ve7xen on January 31, 2013, 07:24:43 pmYes it does!

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 31, 2013, 08:37:34 pm
content: I'm not saying it's not, but what makes you say it's tin whiskers?

author: flolic
author_rank: Frequent Contributor
timestamp: January 31, 2013, 09:04:14 pm
content: Well, I am not absolutely sure, but I don't know what else could it be?

author: w2aew
author_rank: Super Contributor
timestamp: January 31, 2013, 09:20:16 pm
content: Perils of not learning from history. Lead was originally introduced into solder formulations in order to reduce/eliminate the formation of tin whiskers, wasn't it? Now with all the lead-free solders, aren't going to see the same thing again? Or, have they now included some other alloy to reduce the whisker growth?

author: FenderBender
author_rank: Super Contributor
timestamp: January 31, 2013, 10:18:36 pm
content: Awesome pictures. It would have just looked like dust to me.Hackensack, NJ...That's 10 minutes from my house! Hopefully they don't use that solder anymore...if they still exist.

author: FenderBender
author_rank: Super Contributor
timestamp: January 31, 2013, 10:21:37 pm
content: Quote from: w2aew on January 31, 2013, 09:20:16 pmI don't know, there's billions of dollars, maybe more, worth of lead-free equipment out there...If they start going bad...someone has some explaining to do...RoHS...

author: marshallh
author_rank: Unknown
timestamp: January 31, 2013, 11:27:48 pm
content: Worst is when this happens on your 0.8mm pitch BGA and you can't see it with normal means... Nightmare material

author: mamalala
author_rank: Unknown
timestamp: January 31, 2013, 11:51:57 pm
content: Quote from: FenderBender on January 31, 2013, 10:21:37 pmI'm pretty sure they are already working on, or have it ready, an ROHS alloy that will have predictable whisker grow. "Predictable" as in "Those whiskers wont grow fast enough to cause havoc during the warranty time". It may well be some CT territory, but i guess that many manufacturers are actually quite happy about those whiskers. After all it means that sooner or later things will fail due to them. And then they have something to point the finger at, to shift the blame....Greetings,Chris

author: FenderBender
author_rank: Super Contributor
timestamp: February 01, 2013, 12:58:45 am
content: I hate how the world works.

author: w2aew
author_rank: Super Contributor
timestamp: February 01, 2013, 02:38:36 am
content: Quote from: FenderBender on January 31, 2013, 10:18:36 pmLooks like we're neighbors, sorta. I'm about an hour from Hackensack.

author: Moshly
author_rank: Regular Contributor
timestamp: February 01, 2013, 02:40:57 am
content: Here is a few pics from a Phillips PF900 radio (made in AU mid 80's).Its interesting that the whiskers appear to be attracted to any potential.Note the 2 crystals shorting out the laser cut resistor (top left).

author: TerraHertz
author_rank: Super Contributor
timestamp: February 01, 2013, 03:30:19 am
content: Quote from: FenderBender on February 01, 2013, 12:58:45 amMe too, and in so many ways.Planned obsolescence - one of the stupidities that will be our species' undoing. And thus Earth's too.DRM is another. Ironically, I wanted to post a link to the excellent video "The Light Bulb Conspiracy" here.Checking my link is still current, encountered ""Pyramids of Waste (Full Len..." This video is no longer available due to a copyright claim by Media 3.14."Anyway, I think this one works: htt p://www.youtube.com/watch?v=4WPrTk90VZM(URL mangled to prevent inclusion of image here.)I discovered for myself that the tin whiskers problem is real, when some small metal can TO-18 transistors on an old board had grown hairs. It's very pretty, and a fascinating bit of material physics, but I think I'd rather have the lead included please.Toyota of course is still denying that tin whiskers in their car accelerator pedal sensors killed anyone. NASA disagrees:http://nepp.nasa.gov/whisker/reference/tech_papers/2011-NASA-GSFC-whisker-failure-app-sensor.pdfgoogle: tin whisker car accelerator deathEdit: Hmmm, I hadn't realized NASA has a whole page devoted to tin whisker problems.http://nepp.nasa.gov/whisker/

author: HardBoot
author_rank: Regular Contributor
timestamp: February 01, 2013, 04:52:13 am
content: Quote from: marshallh on January 31, 2013, 11:27:48 pmAnother reason for me to avoid BGA.Tin whiskers are a problem the industry doesn't really care about because it kills things long after their creation, which means, whoops dead product buy a new one... but it's dangerous in many environments, medical equipment failures.Tin whiskers are crystals of tin... I don't know how they're formed but all sorts of material will grow crystals under the right conditions... tin just happens to need hardly any motivation to do it, molecules like being in a lower energy state and a crystal is it's most natural form.

author: BravoV
author_rank: Super Contributor
timestamp: February 01, 2013, 04:59:41 am
content: So tinned pcb at the copper without solder mask should be avoided ? That thin layer must be pure tin right ?

author: digsys
author_rank: Unknown
timestamp: February 01, 2013, 05:20:45 am
content: I've repaired DOZENS of items that failed due to use of lead-free. In MOST cases they were very expensive ECUs and other "computers" from8-10 year old Mercedes / Audi and other European cars, before they got the lead-free exemptions !! Huge failure rates at the 8-10 yr mark.Another common fault is the lead-free "separating or corroding" component leads which weren't of a "perfect" mix. In an Audi case,I replaced every one of dozens of ONE type of capacitor from a supplier that must have got his metal mix wrong. Some leads were totallycorroded. Then they started the exemptions, which gives you a HINT, and I believe at one stage, because there were SO many industriesapplying, they changed the rules. Not 100% sure what they did, but easy enough to google. I still do a few here and there.A very environmentally just cause, but totally screwed up, and as said ... maybe manufacturers just thought .... hey this may not be such abad thing ... 8-10 yr life !

author: TerraHertz
author_rank: Super Contributor
timestamp: February 01, 2013, 05:25:37 am
content: Quote from: BravoV on February 01, 2013, 04:59:41 amIf it's traditional solder, ie contains lead, pcb 'tinning'neverforms whiskers. Tinned pcbs used to be totally reliable, except where corrosion or mechanical stresses broke solder joints or tracks.Then along came RoHS' "lead is BAAAAAD mkay!?" and suddenly we don't know any more if 'tinning' may be exactly that (and hence failure prone due to whisker shorts.)I flatly refuse to believe the people who forced RoHS on us all, didn't know or were never told about tin whisker growth. Useful idiots lower down in the structures may have been ignorant, but not the people who initiated this bullshit. All part of the intended destruction of industrial capacity of the developed nations, per Agenda 21.

author: GK
author_rank: Super Contributor
timestamp: February 01, 2013, 09:46:20 am
content: Quote from: TerraHertz on February 01, 2013, 05:25:37 amYes, err.... OK. Let me guess - it's them Zionist's, right?

author: SLJ
author_rank: Frequent Contributor
timestamp: February 01, 2013, 11:37:10 am
content: Interesting. I have to deal with pot metal disease on vintage equipment from the 1930s, 40s, and even the late 1950s frequently. I'll have to keep an eye out for the whiskers from now on.

author: tom66
author_rank: Super Contributor
timestamp: February 01, 2013, 01:31:36 pm
content: Quote from: TerraHertz on February 01, 2013, 05:25:37 amA few Xboxes and laptops failing is not going to bring down industrial capability of nations. It's just going to piss off customers eventually but after some time people will get used to it and accept it as normal -- it's already happening. Military and some medical equipment is also eliminated from RoHS because the reliability problems are known. If anything, planned obsolence does help industrialised economies because it increases spending, and if customers have no option BUT unreliable electronics, then it will work out well for companies.

author: Unknown
author_rank: Unknown
timestamp: February 01, 2013, 03:18:47 pm
content: This was a problem way back in the 1970's production of transistors e.g. OC170 and alike germanium types, with a screening can... years latter, whiskers grow within the can to the internal junction, shorting out the device to ground; a quick and easy fix was to cut the screening leg, only if it would no cause RF problems.

author: amyk
author_rank: Super Contributor
timestamp: February 01, 2013, 08:13:40 pm
content: Note that the whiskers are a problem mostly for low energy electronics; at anything higher than tens of mA they'll fuse.

author: jahonen
author_rank: Super Contributor
timestamp: February 01, 2013, 08:57:15 pm
content: Quote from: amyk on February 01, 2013, 08:13:40 pmNot necessarily, with high energy circuits, they can provoke destructive plasma arc which can cause very serious situations in spacecrafts etc.Not directly relates but whiskers have been found in nuclear plant control circuits, causing unplanned shutdown:http://nepp.nasa.gov/whisker/reference/tech_papers/2005-dadonna-nuclear-reactor-shutdown.pdfRegards,Janne

author: Neilm
author_rank: Super Contributor
timestamp: February 01, 2013, 10:27:44 pm
content: Quote from: amyk on February 01, 2013, 08:13:40 pmBy low energy, do you include High Voltage? Tin whiskers can and will reduce the clearances which will cause safety issues.Neil

author: N2IXK
author_rank: Frequent Contributor
timestamp: February 02, 2013, 02:40:56 am
content: Quote from: w2aew on February 01, 2013, 02:38:36 amI'm about 10 minutes away, as well. And I know somebody who used to work for Power/Mate, as well. Ended up with lot of cool junque (and a few working power supplies) from their dumpsters when I was a kid learning electronics. They went out of Hackensack years ago, and I believe the company is completely defunct now.

author: ignator
author_rank: Regular Contributor
timestamp: February 02, 2013, 10:52:36 am
content: Quote from: TerraHertz on February 01, 2013, 05:25:37 amI agree the "government" didn't know that by removing lead from electronics, they would introduce a bigger problem then the ECO problem they were trying to solve. No one looks at the big picture. The manufacturing process just to make an integrated circuit uses how many toxic materials (ending up as waist, but in China/3rd world manufacturing sites, not Europe), the PWB manufacturing has how many toxic processes just to make the initial laminates, that the PCB vendor manufactures by etching via photo lithography processes that have how many toxic agents. They just didn't want that lead in land fills. But by not looking at the big picture, they cause early failure of electronics, that have much more environmental impact with all the sub component manufacturing.Then there is electronics you don't want to fail used in aircraft and worse nuclear power plants. They won't be safety problems, as there is redundancy (and tin whiskers are not common mode faults if redundant channels have correct design separation), but it's very expensive when an aircraft is grounded waiting for a replacement box to be shipped to BF_Egypt and customers that can't go where they paid the carrier to take them. Maybe the solution would have been RECYCLE your dead or unwanted electronics (with some sort of draconian death penalty).ignator

author: TerraHertz
author_rank: Super Contributor
timestamp: February 02, 2013, 12:12:50 pm
content: Quote from: GK on February 01, 2013, 09:46:20 amI presume by your deliberate 'them' implying stupidity, you believe there's no such thing as Agenda 21, Zionism is just a meaningless word used by kooks, and anyone suggesting the existence of high-level conspiracies to achieve global ideological objectives must be a retard.Well, to quote a well known phrase, your failure to educate yourself does not make me a wacko.Let's start with Agenda 21. Doesn't exist, right? Sorry, I'm afraid the UN disagrees. From a UN site:http://sustainabledevelopment.un.org/content/documents/Agenda21.pdfOr perhaps you'd prefer an Australian government mention?http://www.environment.gov.au/about/international/uncsd/publications/pubs/agenda21.pdfThough, such publicity pieces are all fluffy bunnies and kittens on the surface of the verbiage. I'm merely establishing that 'Agenda 21' is an official UN initiative. For what Agenda 21 really aims to achieve, you'll have to dig deeper.Here's a few starter hints:http://everist.org/archives/links/!_Agenda_21.txtI'm sure you'll get right on it, since cognitive dissonance is so much fun.As for Zionism, it exists, is a very evil extremist and racist political creed/cult, wields a lot of influence worldwide, but doesn't really have much to do with Agenda 21, except very indirectly. If you suddenly felt a burning need to educate yourself about the Powers of the world and how politics really works, you could dedicate a year or two to studying Zionism. Maybe start inhttp://everist.org/archives/linksunder 'Z'.But I wouldn't recommend you do. You'd only make yourself depressed, and since I gather from the manner of your response (ad hominem plus strawman) that searching for the truth of things isn't high on your priorities, the depression would be to no useful purpose.As for the RoHS initiative being a component of the Agenda 21 de-industrialization efforts; well obviously that's just me guessing. Was it stupidity, or planned that way? There are too many 'accidents' that all produce results tending in the same direction. Lots of other reasons too, why I take the 'planned' view.

author: GK
author_rank: Super Contributor
timestamp: February 02, 2013, 12:25:33 pm
content: Quote from: TerraHertz on February 02, 2013, 12:12:50 pmOK, just "indirectly" then - I thought so. Last time I clicked on one of your links (since removed by admin) I ended up on page of a deranged and bigoted anti-Semite ranting about a conspiracy of the Jews to infiltrate the Wests libraries and tear pages pages out of important books. I'm not going to click anymore of you links, nor entertain any of your inane presumptions.I have many misgivings about the lead-free fiasco, but you are a few cans short of a six pack.

author: TerraHertz
author_rank: Super Contributor
timestamp: February 02, 2013, 02:24:20 pm
content: Quote from: GK on February 02, 2013, 12:25:33 pm"you links"? Heh...http://sustainabledevelopment.un.org/content/documents/Agenda21.pdfhttp://www.environment.gov.au/about/international/uncsd/publications/pubs/agenda21.pdfYeah, what a bunch of kooks."There is a principle, which is a bar against all information, which is proof against all arguments and which cannot fail to keep a man in everlasting ignorance - that principle is contempt prior to investigation."-- Herbert Spencer, 1820-1903Incidentally, what did I say right after the Jim Stone link? "No further comment"Gosh, could I have been posting it as an example of something? Bit too subtle for some, apparently.Now I'll leave you to your six pack analogies. Personally, I don't drink.

author: GK
author_rank: Super Contributor
timestamp: February 02, 2013, 11:55:10 pm
content: Quote from: TerraHertz on February 02, 2013, 02:24:20 pmYes, there you have a clear outline no less of the "intended destruction of industrial capacity of the developed nations"QuoteWho is barring "all information" now?QuoteActually you did offer further comment after the link was deleted; words to the effect that the article matched your real world experience. Not subtle at all.QuoteThat's good. I'd hate to read one of your posts after you've had a few.

author: ignator
author_rank: Regular Contributor
timestamp: February 03, 2013, 04:54:25 am
content: I'm so sorry, I didn't see that trip wire (terrahertz) with zionism and agenda21. This is so nice for a change to be at a hobby forum, that does not turn 99% political.Also thanks for the link to the 2011 NASA report.I just retired from working on avionics, RoHS has become a real pain. And we contaminate our solder joints with lead, as avionics are still allowed into the EU with lead. Our products use conformal coat, and we underfill BGAs with non reworkable epoxy's. Which also helps with the tin whisker abatement.ignator