Hi all, We recently ran across a whitish spotty/hazy laminate condition first spotted after a couple of boards had gone thru assembly (see attached PWB.jpg picture showing condition on laminate between connector fingers on assembly). The condition was brought into question and after some investigation, we learned that such condition is a pre-existing one at the bare laminate level that normally occurs with Arlon's 33N polyimide laminates due to a micro-disperse second phase of the flame retardant brominated sytem. And apparently, this condition is seen to varying degrees within the 33N (see attached pictures: 113_1335a.jpg - more so, 113_1352a.jpg - less so). Also attached is Arlon's letter that explains this laminate appearance, concluding that it's not a laminate defect. How have other end-users of this 33N laminates dealt with this laminate appearance at the assembly level? Has it caused any grief and how had the assemblies been dispositioned? Of course this condition, when it exists, can only be seen under magnification, but even then, the whitish spotty/hazy appearance can be confused with other possible laminate imperfections/defects when seen by the inexperienced, like we were. I'm not even sure if we're able to automatically say this is the condition we have when similar appearances are seen on future finished assemblies. Any feedback you have is greatly appreciated. Thank you, Dung Q. Tiet Lockheed Martin Space Systems Co. Sunnyvale, CA Tel: 408-756-2365 Email: [log in to unmask]