['LIVEWIRE?']

Attached is a photo of the PSU used in the Dr. Dre Beatbox. It's similar in principle to most other SMPSUs, though instead of an optoisolator, the rectified HT o/p, smoothed by two 220uf/200v. Electrolytics in series, is coupled to the primary of the bigger of two transformers via a 2uf 250v Metalized poly. capacitor. To reply to your post, Refugee, I didn't think about that when testing the FET, but thanks for reminding me. I've since discovered that the 2uf capacitor is faulty - it reads much lower in value than that.