Hi Folks, We've been use one of the linear transformer in our product for a while and suddenly in one lot the transformer has failed the exciting current test limit at higher votage(132V). This is a 120AC/20VAC@750mA linear transformer. Supplier is trying to figure out what went wrong but still find no clue. -What should I investigate? -Is there any measurement I can do to check whether the problem come from the core or the winding? -Can this related to a core saturation? Can we look for problem with core saturation with oscilloscope? Sorry if there seem to be too many newbies question. I was been pretty much in digital domain for so long. Thanks, Kudjung.