Steve: Good to see your name in print--- duPont Pyralux acrylic adhesive has poor insulation resistance particularly at elevated ie above 75C temps. It is also notoriously susceptible to moisture absorption which adds to its conductivity. I believe your problems will be significantly reduced if you avoid Pyralux acrylic. The problem could also be traceable to poor inprocess rinsing or cleaning. There are several standard methods for measuring IR in adhesive structures, most involving an etched interdigitated grid. If you produce such patterns and start a history of the measured values you will be able to track your cleanliness. Be sure to run the t est at elevated temperatures because this is where the trouble starts. You could have an undercured structure. Any ionic contamination will give trouble, particularly at this high voltages. Is this necessary? Most equipment today runs at very low voltages which partly explains the wide use of duPont Acrylic. Is there any tin or silver plating on the circuitry? Tom Stearns 3 Brander Court Nashua NH 03063 603 889 2522 --------------------------------------------------- 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 -----------------------------------------------------