I don't claim to be an expert but I do not believe it is CAF. The following is some information that helps define CAF for some of the members that are not familiar with the topic. What is CAF? CAF is an acronym for Conductive Anodonic Filament growth. Bell Labs first identified CAF in 1976. Field failures were later identified in 1980. CAF is formed as a result of several events. As an epoxy resin system is heated there is the possibility that the resin shall separate from the fiberglass reinforcement. The separation forms an open channel at the resin to fiberglass interface along the length of the fiberglass strand. This separation is random and next to impossible to find by X-section. When an assembled board is exposed to high humidity the CAF channel fills with water. The copper corrodes and an electrochemical pathway develops. The water acts as an electrolyte, the copper circuitry becomes the anode and cathode and the operating voltages act as the driving potential. Basically a filament containing copper grows along the channel formed at the epoxy resin and glass interface. The growing filament ultimately forms a short between two unlike conductors resulting in a field failure. I don't see how CAF can form in a freshly assembled board. From the information I have read on the subject it seems to take time (months not days) for the copper filament to grow. However, nothing is impossible. I would like to know what the laminate system is. FR4 is too generic a term now. Nelco -6, Isola FR406, IS410... The reason why I ask is that the phenolic resin systems have a lower bonding strength when compared to traditional dicey-cured resin systems, IE FR4. Mechanical force can cause damage to the phenolic resin systems. --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------