Hi Technetters,
An assembly shop here got a very puzzling result.
They received in 1995 a shippment of bare boards: simple multilayer boards, made of glass reinforced polyimide. The finishing was reflowed Sn/Pb and soldermask.
The shippment was 100% visualy examined and then assembled with the exeption of a few boards that remained in stock.
This month, the remaining boards were examined again and showed severe signs of measling and delamination. They are sure none of this existed two years ago (because then the lot would have been scrapped). 

Has anybody ran into such phenomena or can offer any explanation ?  I must add that they are now worried about the quailty of the boards they have supplied two years ago.

    ************************************* 
    *          Yehuda E. Weisz              
    *  e-mail: [log in to unmask]
    *  Tel: 972-3-5240362                    
    ************************************

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