I've fixed them. They're not hard to fix. Yes, it's a switching regulator, but it's a benign one, running off 30V AC from an isolating transformer. That can source enough current to blow transistors apart (see below) but it's a lot nicer than a switcher running off the mains directly. Whatever you do, don't disable the overcurrent trip. If you do, you can bet that murphey's law will cause the corwbar to fire, and then you'll have a lot of silicon blown apart as the current through it goes sky high. Don't ask how I found this out, suffice it to say I had to replace a handful of transistors.... Anyway, start by checking the fuse (yes there is one). Then make sure you're getting a sensible votlage across the large capacitor. This should be about 40-odd votls IIRC (full wave rectified version of the AC input). Then check the chopper transistor, other transistors, etc. The IC -- a good old 723 -- rarely fails unless there are other faults too. Oh yes, make sure the screw terminals (large capactiors, inductor block) are tight and making good contact. I will pretend I didn't read that :-) -tony