Ken Once coated, I believe the only test likely to be revealing in the relatively short term is the pressure cooker test. Put some water in an autoclave or a domestic pressure cooker and suspend the circuit to be tested well above the water level. Seal and bring to the boil (~120 deg C). Leave for 24-48 hours, making sure the water never boils dry. Take out the circuit and check under 10 x magnification for vesication, blistering or mealing. Any hygroscopic and potentially dangerous residues trapped under the coating will be revealed. A very simple and revealing test. Brian Bloomquist, Ken wrote: > I have a question regarding a test for flux contamination on conformally > coated boards. > > I know all about testing uncoated boards but was wondering if there are any > tests for type UR coated boards? > > Does a temperature soak do any good at bringing problems to the surface? > > Does baking cause any remaining flux to become conductive? > > Does a humidity/temperature soak do any good? > > What were looking for is a parallel electrical path that might reduce the > value of a small SMT resistor. > > Thanks in advance, > > KennyB > > --------------------------------------------------- > Technet Mail List provided as a free 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/html/forum.htm for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > ----------------------------------------------------- > > > --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------