To the forum: Currently, I am testing a printed-circuit-board-mount transformer. There is one primary winding and three secondary windings. There are two powdered-iron 'E' cores that are epoxied together around the bobbin to provide the core for the transformer. I have a problem where the inductance and the Q of the primary coil drop way below normal past 1500 Hz with a signal of 100millivolts AC applied. I suspect that there is a shorted turn of wire that may be causing this. Generally, there is maybe 1000+ turns of wire on the transformer, and the chances of finding a marginal short-circuit with merely a microscope and the eyes is a 'needle-in-a-haystack' type of chance. Is there some method that would incorporate an electrical signal that would enable me to find a short-circuit in the primary winding? Any and all ideas are welcome. Questions are also welcome. Regards, Kelly Schauf SIGNATURE: For my webpage containing links to Quality and Electrical Engineering as well as Failure Analysis (Electronic, primarily) and ISO9000, go to http://web.gmtcom.com/~k3jsch ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com ############################################################ #### TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ############################################################ #### To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ############################################################ #### Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ############################################################ ####