Refluxing the board, lightly brushing the effected areas and rewashing 
should remove the lead oxide.
     Has voltage been applied to these boards yet or are you finding the 
lead oxide before any electrical testing?  Are the locations consistant?  Is 
it only on the pads or can it be seen between pads, on the board surface?

     Norm Dill
 ----------
From: TechNet-request
To: IPC
Subject: White residue/lead oxide
Date: Tuesday, May 07, 1996 10:16AM

We have a white residue problem at another division that has been analyzed
using FTIR and SEM EDAX that has shown it to be lead oxide.  The white 
residue
is located on pads/solder fillets.  The following process is used:

a.  Yokota flow solder (preheat 220F topside, 495F solder pot (less than 3
seconds), conveyor speed 3.5 ft/min)
b.  Kester 197 foam fluxer (rma)
c.  Cleaner is Bioact EC7R in a Ney spray under immersion or ECD batch
diswasher.  Temperature of EC7R 90-95F, Rinse waters 130F.

The white residue is observed after cleaning and is insoluble in alcohol
water/EC7R.

Any input on things to look for would be greatly appreciated.  We are 
running
tests at other divisions with different flux chemistries/board 
design/process
parameters.

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