There is no such thing as a dumb question! I suggest you check out two 
     areas: 1) the sockets; 2) the assembly process. Check out the sockets 
     to make sure that the proper plating thicknesses are being supplied. 
     Thin or bad plating will result in copper corrosion. I would also 
     examine the assembly process to see if you are leaving any moisture or 
     flux residue in the sockets that would lead to corrosion. Don't write 
     off the testing portion of assembly - condensation during thermal 
     cycling can be a "hidden" moisture source.
     
     
     
     Dave Hillman
     Rockwell Collins
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______________________________ Reply Separator _________________________________
Subject: FAB:  Green rust
Author:  [log in to unmask] at ccmgw1
Date:    5/16/96 11:13 AM


     
          I'm almost embarrassed to ask this one.
     
          Green Cu oxide shows up on socket pins after about three 
          months in the field.  Very little shows up before assembly, 
          or shipment.
     
          Is this as simple as the wash not being monitored properly?
     
          I'll listen to anything as technical as anyone wants to get 
          from proper p.c. fab methods to the chemistry behind it.
     
          Thanks in advance.