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. [log in to unmask]