Tin whisker problems????

It's very unlikely that they were lead-free in '05. It was probably just some tartar or plaque.

Bob

Could have been, hard to say for individual divisons:

If you still have access to that drive: Are the solder joints looking a bit dull? Does the solder have a hard time melting at normal tip temps? That would point to lead-free. Then it might make sense to check it for more whiskers under a microscope

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Regards, Joerg

http://www.analogconsultants.com/

I keep seeing the occasional, same, report about satellites failing due to tin whiskers etc. ( nope, no url)

I was just wondering how "they" know, did they send a guy up to have a look at the pcb's?

Martin

Next time the occasional same report shows up read it. If it is the same one I have occasionally read they duplicated the problem on the ground, and merely ass-u-me-d that the causes were the same.

But of course the wiskers grew on tin plating, not lead free solder. The issue is not and has never been with whiskers growing from lead free solder. There have never been any documented failures from whiskers growing on the SAC or better lead free solders. The issue is and has always been whiskers from the tin plating on component leads, sometimes used instead of the old tin-lead plating. Whiskers cannot grow if the tin plating is completely wetted by solder; either tin-lead or lead free. Using tin-lead instead of lead free solder with components having tin plating offers absolutely no protection against whiskers growing from the tin plating on component leads not completely wetted by solder. If you want immunity from tin whiskers either insure all tin plating is entirely wetted with solder or don't use components with tin plated leads.

All of the major manufacturers figured this out long ago, which is why we aren't seeing the massive failures some on this NG have predicted. So I agree with the poster who speculated that the problem was more likely tartar and plaque than tin whiskers :-).

qrk hath wroth:

I don't think so. IBM/Hitachi was shipping some really awful disk drives from about 2000 to 2005. There was a class action against Hitachi on the 75GXP series:

(autopsy)

They symptoms were somewhat similar to what you experienced. The boot loader would fail to load from the hard disk because of read errors. The drive would either not be recognized or not boot depending on which point in the boot load process was failing. What was weird was that removing the drive and retesting would sometimes induce a miraculous recovery. I usually immediately made an image backup at this point as it always failed later.

Incidentally, I just recycled about 40 IBM/Hitachi Deskstar drives (mostly IDE) which is about a 2 year supply of failures. Disassembling some of the drives showed the same failure as the aformentioned autopsy.

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Jeff Liebermann     jeffl@cruzio.com
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"Dull"???? Lead free tin/silver solder is rather shiny and neet looking...

The hand-soldering at one client was shiny. However, all the industrial lead-free stuff I've seen so far was dull and had failure rates several times higher than non-RoHS. When it was for the lab I just re-soldered the whole board with leaded and the failures went away.

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Regards, Joerg

http://www.analogconsultants.com/

I think I'll buy your explaination. Although, this particular drive wasn't recognized by the BIOS. All the other failed IBM drives I've came across were recognized by the BIOS, but, failed to boot due to corruption or some other read problem. I've seen IBM drives die within

1 week in the early 2000s. Then I ran into Maxtor drives going bad shortly thereafter. Now I'm using Samsung. See how long it takes for them to go into early failure mode.

Mark

Martin Griffith mart_in_medina@ya___.es posted to sci.electronics.design:

I actually doubt that you will see this issue in satellites. The reliability of expensive, place it and use it until it dies technologies do require avoiding and preventing any failure mode preventable or avoidable. The non-lead solder issues have been known since the 1960's or earlier.

qrk snipped-for-privacy@spam.net posted to sci.electronics.design:

Speaking of disk drives and early failure, i bought a couple of Maxtor "One-touch" fire-wire/USB drives a few months back. I was using on as an on line drive for eventual migration use. It failed, i decided to piss off the warranty and took apart the case, and found a normal Seagate drive inside. I placed it in another case it the drive proper was fine. I tested the mini-brick power supply and it was fine. I checked the the internal PS to the external enclosure and it is dead. There is no fan in the one touch enclosure. Make any conclusions you like.

They don't make 'm as good as they used to be. I had to replace the Western Digital hard drive in one of my servers after 11 years due to a power outage yesterday.

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I had one of those die in exactly the same way. In my case I had to get the data off it. I did similar to you stuck the drive in a machine backed it up then wiped it. But I put it back in the case and RMA'd it. The new one works just fine.

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Best Regards:
                     Baron.

That is the typical result everyone gets when they try to "drop-in" SAC lead-free solder in a tin-lead process, merely setting the temperature up for the higher melting point. But few manufacturers actually ship anything like that. Look at the lead-free solder joints in a new cell phone or a new PC motherboard. That is what a properly done lead free solder joint should look and perform like.

In general, all new soldering equipment is required to handle the tight profiles and nitrogen inerting required for good results with the low cost SAC alloy; those stuck with older equipment can only get good results with some of the relatively expensive 4 component proprietary solders, and then only if it is good older equipment capable of accurate time/temp control. Only some fluxes will produce good results in air. A bit of a pisser for the small manufacturer, but not an excuse for shipping boards with bad solder joints. The procedures required to obtain good lead-free solder joints have been published for anyone to read and follow. I can concieve of no valid excuse for the incredibly poor workmanship you report, and completely reject the notion that lead-free solder is in any way to blame. If it were then all new cell phones and computers would be unreliable, and they aren't.

JosephKK hath wroth:

I happen to be catching up on my magazine reading today and found in the Sept/Oct issue of Military Embedded Systems magazine: "The costs of doing business in the new RoHS World"

The article notes that 3 satellites have probably failed due to tin whiskers. Actually, the list in the article is incomplete. See:

Seems to be a problem with the early Boeing HS601 series of birds:

More from the Mil Embedded Sys article:

Matte (dull) tin seems to be more effective at preventing whiskers than shinny tin.

Conformal coating doesn't help.

TI estimates that their conversion to RoHS will save the equivalent of about 10 automobile batteries in lead.

Ford had some automobile computahs fail with trace corrosion when the tin traces came in contact with modelling clay, which had a high sulfur content.

There have been nuclear and conventional power plant shutdowns due to tin whiskers.

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Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Joerg hath wroth:

Umm... It's suppose to be dull to reduce whisker growth. See:

"It is well documented that internal compressive stress is a driving force for the growth of tin whiskers. This stress can come from the naturally occurring compressive stress that occurs when tin is electrodeposited from a plating bath. The more organic brightening additions in the plating bath, the higher the internal stress in the tin deposit will be. The highest stressed deposits are obtained from baths that yield bright or specular (mirror-like) deposits, often used for decorative electroplates. Somewhat less prone to whiskers is the matte or dull finished tin, which is usually lower stressed, but still will grow (usually fewer and/or shorter) whiskers."

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Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Jeff Liebermann snipped-for-privacy@cruzio.com posted to sci.electronics.design:

Thank you for your very informative post. I never knew that HSC and apparently most of Hughes S&CG seems to have been bought by Boeing.

Yes, it's a new field. Yet the Eurocrats took it upon themselves to declare that "it's going to be ok". We'll see. I have yet to see a longterm study about lead-free, like some experiment that was started, say, in the 60's. Anything else is playing with fire.

--
Regards, Joerg

http://www.analogconsultants.com/

JosephKK hath wroth:

What I found interesting is that the failure ocurred in relays.

which are apparently used for on-off switching. I would have expected whisker bridging in ciruit board traces and tin plated connectors, but not a mechanical relay. The article mumbles that the tin whisker shorts the relay to the case, causing a fuse to blow. That means that either the tin whisker is huge, or the fuse is really tiny. I would imagine that the very thin tin whisker would blow long before any fuse would blow. Methinks something is fishy here.

Boeing bought the Hughes Satellite biz in Jan 2000 for $3.75 billion in cash. Much of the cash went to prop up PanAmSat and pay for DirecTV aquisitions.

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Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

I read they typically blow in the 30mA range. Fishy indeed.

Tim

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