Juan T. Marugán a écrit :

>Hello teachers,
>
>we have the following problem in some class 3 units: we have detected a
>white stuff inside the contacts of female connectors. It could be the main
>cause of the failures found during testing. Our thought is this substance
>could be due to a reaction between the rosin flux used when soldered the
>connectors whit the cleaning solvent (IPA)
>
>Two questions:
>
>1) Could you recommend a solvent to remove these residues. We have tried
>with 141-b, but it could damage some parts of the unit.
>
>2) We would like to send a contaminated connector to a lab for analisys.
>Could you recommend a technique to determine these substances?
>
>Thank you for your help.
>
>Juan T. Marugán
>Indra Sistemas SA
>España
>
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>
Juan,

In such a case, I would recommend to make a FT-IR analysis. This 
analysis is even more efficient when made in comparison with other 
substances.
We have an internal lab which does this kind of analysis for years.

Best regards,

Arnaud Grivon

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