I'd have the pins themselves checked by XRF for proper Au/Ni platings.
     I had this happen one time and found that the Ni plating on the pin 
     was down as low as 20-50 u inches and the copper migrated up thru to
     the gold. It also turned Green!
     
     Groovy
______________________________ Reply Separator _________________________________
Subject: FAB:  Green rust
Author:  [log in to unmask] at SMTPLINK-HADCO
Date:    5/16/96 12:02 PM


     
          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.