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. [log in to unmask]