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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