What kind of failure mode? On Wed, Oct 30, 2013 at 7:04 PM, Ed Popielarski <[log in to unmask]>wrote: > Good Morning Esteemed Colleagues, > > We have recently been experiencing increasing failure rates of an SMT (5.2 > X 5.2 X 1.2 mm) transformer. The first build in September showed about 6% > fallout. Subsequent builds from the same reel have increased to 25% most > recently. These components have been stored in a normal ambient > environment. I have verified and re-verified reflow conditions are well > within manufacturer's specifications (confirmed by the manufacturer). > > When this problem was first identified, I "dissected" one of the failing > devices and found the wire pair (primary and secondary) in good condition > on the outer windings, but as I continued to unwind down to about 1/3 deep, > the insulation began to stick both side by side and to subsequent layers > which would "fuzz" as it was pulled apart with exposed copper implied. > > I am beginning to suspect "cold flow", a problem that was prevalent in the > days of wire wrapped backplanes. > > Has anyone experienced a similar condition? The manufacturer has been > "working on it" since mid-September and has yet to provide any root cause > and/or solution. > > Any insight would be appreciated. > > > Ed Popielarski > Engineering Manager > > [Description: FullLogo] > 970 NE 21st Ct. > Oak Harbor, Wa. 98277 > > Ph: 360-675-1322 > Fx: 206-624-0965 > Cl: 949-581-6601 > > > https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A > > > ______________________________________________________________________ > This email has been scanned by the Symantec Email Security.cloud service. > For more information please contact helpdesk at x2960 or [log in to unmask] > ______________________________________________________________________ > -- Best Regards, *Reuven Rokah* Mobile: 972-52-6012018 Tel: 972-3-9360688 Fax: 076-5100674 <http://www.rokah-technologies.com/>[log in to unmask] [log in to unmask] www.rokah-technologies.com ** This e-mail message is intended for the recipient only and contains information which is CONFIDENTIAL and which may be proprietary of Rokah Technologies. If you have received this transmission in error, please inform me by e-mail, phone or fax, and then please delete all of the original files and all other copies exist. ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________