RoHS nonsense, was: Desoldering Chips, was Re: Can someone,

Curtis H. Wilbar Jr. rescue at hawkmountain.net
Fri Apr 9 18:21:15 CDT 2010


I haven't done a lot or research on this... so I may be wrong... but I 
think I've
experienced the woes of (at least first generation) laptops built to 
RoHS standards.

We have a number of Dell laptops at work... we started out 
(unfortunately) with
Inspiron 5100s, and when I came on board, I standardized on Latitudes (D500,
a couple of D505, and D600).  When those were no longer available we 
moved to
D610s.  Then onto D520s, then D530s.  We don't have a current standard 
now....

As best as I know (which is the "I may be wrong" part above), the D500, 
D505, and
D610 used regular lead solder.  The D610 is RoHS (again, I may be wrong, but
this is what I recall from back when we purchased these eons ago).

The failure rate in the Inspirons was't to be proud of.... but that was 
due to a
chassis with too much flex and screws would come loose and short out the
mainboard.

The failure rate in the Latitude D500s was zero, as with the D505s.  We had
one D600 that I retired to being flaky that seemed to originate with the
mainboard or CPU, that at the time it was old enough not to merit more
investment of time.  Other than that, no D600s have failed (and I still 
use one
daily at work).

The D610s however.... I've got 2-3 flaky units, another unit that I 
retired due to
broken solder joints on a connector on the mainboard, and one dead one that
I don't recall what went wrong now.  That is like 5 dead machines.... around
500% more than the D500/505/D600 series units ...

The D520s/D530s haven't failed yet... but they aren't as old as the 
D610s yet
so we'll see in another year or so.....

W/o researching to verify, I attributed this to the lead free solder.  
It being
more brittle I think has lead to breaking of connections due to mechanical
and thermal stresses over time.

I only hope they improved over time, as I have many systems and a laptop
that I personally own that I don't want to die due to brittle solder 
joints or
tin wiskers.... grrr....

Anyone feel free to correct me if I'm wrong on the lead/lead free solder
changover at the D500/505/600 to D610 line in the Latitudes.... I have not
researched it to verify the hypothesis and am simply going by memory.
(which I've learned sometimes can be hazardous :-) )

-- Curt


dwight elvey wrote:
> Hi
>  The tin whisker problem may change the RoHS thinking.
> The problem is that for some applications, they can't allow
> the possibility of a tin whisker killing the device.
>  Military and medical used come to mind. The difficulty
> seems to in locating non-RoHS parts. Many manufactures
> have moved to RoHS only. It is difficult to even make
> things without one or two parts being RoHS.
>  Some claim to have solved the problems with various
> methods. None of these methods have the 10 year history
> to prove them.
>  It seems that it is stresses in the tin that cause these.
> Other metals do this as well ( zinc and cadmium are mentioned ).
>  From a collectors perspective, these systems will be
> soon considered in the 10 year rule ( or 15, 20 etc ).
> We'll be fighting these whisker ghost. We may be doing things
> like acid dips to flush these out. I may be fighting it
> today with an intermittent in a G4 apple.
>  Just my thoughts
> Dwight
>
>  
>  		 	   		  
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