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[aprssig] Kenwood TH-D7A(G) Retired

Amir Findling K9CHP sarlabs at gmail.com
Mon Oct 13 15:11:37 UTC 2008


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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