I would recommend for any of the suggested methods to get hold of 
some (probably good) samples oft the same type of ballast and to 
check the methods before. Thus you know whether the method damages 
any important parts before you destroy your one and only corpus 
delicti. At the best, the known good sample would be fully functional 
even after encapsulant removal.

Good luck... (been there, done that)
Best wishes
Matthias

On 29 May 2009 at 16:11, Terry L. Munson wrote:

> Lenny 
> I would suggest a different non-chemical approach by freezing the
> ballast  and then chipping or cutting the frozen pitch material to get
> to the surface for  Failure Analysis.  We have found that pitch can be
> contaminated and cause  leakage and corrosion problems. We have also
> found that capacitors can leak and  the electrolyte will dissolve the
> material and cause leakage and corrosion  problems.  If you have
> solder joint problems then this approach works well  to investigate
> the joint quality as well.  If you have an question please  call. 
> Terry Munson 765-457-8095
> 
> 
> In a message dated 5/29/2009 2:01:42 P.M. Eastern Daylight Time, 
> [log in to unmask] writes:
> 
> We have  a lighting ballast in for failure analysis and arent sure how
> to get the  encapsulant "tar" from it? This is a lighting ballast and
> we have the metal  covers removed and are left with a ballast assy
> built on a pcb, and covered in  a thick,  black,  semi-pliable,
> tar-like encapsulant. The  tar-like encapsualant smells just like
> roofing tar.  If you lay it on a  piece of notepaper it stains it just
> like roofing tar.  It can be peeled  away just like a roofing tar.  We
> are afraid of poking too much and  damaging components or circuits. 
> Anybody have experience with it? - and  know what it is?  and how to
> let it soak in a pan of something and rinse  this stuff of instead? 
> Better ideas? Thanks in advance, Lenny  Carter Design Engineer ERG,
> Inc. ph (607) 754-9187  x3063 www.ergpower.com
> 
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-- 
Matthias Mansfeld Elektronik * Leiterplattenlayout
Neithardtstr. 3, 85540 Haar; Tel.: 089/4620 093-7, Fax: -8
Internet: http://www.mansfeld-elektronik.de
GPG http://www.mansfeld-elektronik.de/gnupgkey/mansfeld.asc

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