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[aprssig] Kenwood TH-D7A(G) Retired

Scott Miller scott at opentrac.org
Mon Oct 13 16:55:36 UTC 2008


Whiskers aside, lead free processes seem to universally require higher 
temperatures (and greater energy consumption.)  It's additional strain 
on the components, added difficulty in making sure everything is 
compatible, and a disruption to established and proven processes.

The lead-free solders I've worked with also have poorer wetting 
characteristics and make rework more difficult.

All of this for a dubious environmental impact.  I'm sure years from now 
they'll point to a decrease in lead in landfills that coincided with the 
legislation, but how much do you want to bet they'll totally ignore the 
shift from lead-filled CRTs to LCD and plasma displays?  How many iPods 
worth of lead is there in one car battery?

But hey, people will vote to ban dihydrogen monoxide if you put it on 
the ballot and tell them about all the ways it can kill you.  At least 
here in California.  =]

Scott
N1VG

Shanon KA8SPW wrote:
> The article from Beijing University of Technology was done July 2008.  
> The intent was to show it has been a noted problem for some time, from 
> the start, without a solution, and still a problem.  Note how fast they 
> grow in some of the examples.
> 
>   Yes regular leaded solder does grow whiskers too but not at the speed 
> and length of lead free.  Now, with circuits getting even smaller and 
> tighter it is a problem to address and be aware of.  Once the circuit 
> shorts all sorts of havoc will be done. 
> 
>   The quote you quote does say the phenomenon did not show up until they 
> started to reduce the lead content.  In older electronics, equipment was 
> long declared obsolete and scrapped before such an event would happen so 
> it was never discovered.  Old equipment was not worth the trouble to 
> repair.  Why do you think they came out with silver solder as used in 
> Tektronics scopes?
> 
>  Read everything written before you speak.....  I just hate it when 
> people don't read all of what you write.  Stop trying to disprove and 
> learn.  Noone know it all.  I worked over 32 years at a big three 
> automotive R&E center as an electronics technician, just retired at age 
> 53.  I do repairs on everything including surface mount.  They still are 
> struggling with the whisker problem.
> 
> I could add quite a brag line to my email but I do not think it shows 
> any class plus it has nothing to do with this.
> 
> Electronics is just getting started, wait another 10 years and see what 
> comes!  What a great hobby and what a great job it was!
> 
> Shanon KA8SPW
> 
> Amir Findling K9CHP wrote:
>> Well, checking out Shannon's cited source, it looks as if the reports 
>> were from 1992 to 2002 with one single occurrence in 2005. Here is a 
>> quote from that last source 
>> http://nepp.nasa.gov/whisker/reference/tech_papers/2005-dadonna-nuclear-reactor-shutdown.pdf
>>
>> "The tin whisker is a phenomenon the National Aeronautics and Space 
>> Administration
>> (NASA) has been tracking since the 1940s."
>>
>> Shannon, I may be the bearer of bad news, as the Drake TR4 having been 
>> around since the mid-60's, I think it may also potentially suffer from 
>> the same "fate"... :-(
>>
>>     * 73 de K9CHP Amir Findling, Member ARRL, ARRL/ W5YI VE, WAC
>>     * www.K9CHP.net <http://www.k9chp.net>
>>     * Senior K9 Handler
>>     * K9 Certification Tester, NYS Federation of SAR Teams
>>     * 1st Special Response Group (1SRG)
>>
>>
>>
>> Shanon KA8SPW wrote:
>>> My fellow hams:
>>>
>>> Don't be so fast to replace what works.  Another case of a law to 
>>> replace or reduce something before the technology is there to provide 
>>> a solution.
>>>
>>> Take a read about growing "tin whiskers" and lead free solder.  Big 
>>> problem in RoHS circuits.  And it don't take long to show up.
>>>
>>> "There is electrical risk posed by the other major component of 
>>> solder, tin. For reasons that remain somewhat obscure, tin used in 
>>> electronic devices can form what are called "tin whiskers 
>>> <http://nepp.nasa.gov/whisker/>," thin filaments of the metal up to 
>>> 10mm long that sprout from surfaces covered in the metal. Although 
>>> the causes of the whiskers are obscure, the consequences aren't: 
>>> whiskers that bridge two conducting areas can cause short circuits, 
>>> causing erratic behavior or ultimately destroying the equipment. NASA 
>>> maintains a list <http://nepp.nasa.gov/whisker/failures/index.htm> of 
>>> various military, orbital, and medical failures that have been 
>>> attributed to tin whiskers. Presumably, many failures in equipment 
>>> that is not significant enough to warrant a post-failure analysis are 
>>> also the product of tin whiskers."
>>>
>>>
>>>   Notice how manufacturers are keeping quiet about this problem.  In 
>>> some electronics it will take a while and then one day, smoke.  Won't 
>>> be any rigs of today working say in 30 years like an old Drake TR4 
>>> does today.  I won't be buying anything lead free until the problem 
>>> has been solved for some time. 
>>>
>>> Your millage may vary.
>>>
>>> Shanon KA8SPW
>>>
>>>
>>> Sites from the text above:
>>>
>>> "Tin Whiskers"  http://nepp.nasa.gov/whisker/
>>>
>>> "NASA Maintains a list"  http://nepp.nasa.gov/whisker/failures/index.htm
>>>
>>> The article bellow has pictures with time taken to grow the whiskers 
>>> in different enviroments.
>>>  
>>>
>>> *July 2008* - Tin whiskers on _/*Sn-3.8Ag-0.7Cu-1.0Ce/Er/Y 
>>> */*/S/**/older /*/*J*/*/oints/*_
>>>
>>> 	
>>>
>>> *"* 
>>> <http://nepp.nasa.gov/whisker/other_whisker/SAC/2008-Hao-whiskers-SAC-Ce-Er-Y-solder.pdf>*Tin 
>>> Whiskers with Special Morphology **"* 
>>> <http://nepp.nasa.gov/whisker/other_whisker/SAC/index.htm>, H. Hao, 
>>> Y. Shi, Beijing University of Technology, July 2008
>>>
>>>   http://nepp.nasa.gov/whisker/other_whisker/SAC/index.htm
>>>
>>>
>>>
>>> Bernard Tyers wrote:
>>>>
>>>> On 13 Oct 2008, at 07:29, Arno Verhoeven (PE1ICQ) wrote:
>>>>
>>>>>
>>>>> and believe it or not... China has come up with their own set of RoHS
>>>>> requirements.
>>>>>
>>>>> http://www.chinarohs.com/
>>>>
>>>>
>>>> "It's not Just Another RoHS. It's CHINA RoHS!"
>>>>
>>>> This is a joke? Yes? I wonder if they will have a RoHS rating for 
>>>> Bindeez beads..
>>>>
>>>> I, for one, am glad that the EU (one of the good things they have 
>>>> done recently) are removing Pb from solder. The one time I had to 
>>>> get myself near a large scale soldering/manufacturing station it 
>>>> wasn't pleasant. And I was there only for a few weeks.
>>>>
>>>> Now, if we can make some head way on other poisonous chemicals 
>>>> (mercury, PVCs, flame retardents) it would be even better.
>>>>
>>>> regards and 73,
>>>> bernard/ei8fdb
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