Thanks Don & Mark, That's what I suspected, but I wondered about U5 & 6 too, whether they may may have been stung further down the schematic. I'll replace the diodes tomorrow when it's light. I have a small supply of 1N5711's here in my junk box. Then it'll be clear if there's more than just the diodes that've turned to toast.
Mark, looking at the dismantling involved to get to the fiddly location of D16 and 17, I think it'll be just as easy to replace the diodes and be done with it. Lifting one end to check would be a good idea though, if they were in a less awkward location. This is an interesting failure. I wonder if the high voltage you'd expect on the capacitor of this small loop antenna might have caused this diode-frying?? I did disconnect the coax from the back of the loop tuner (de-energised of course) at one stage to connect my antenna analyser to retune it to another band. The problem manifest after reconnecting the coax to the K2. The SWR was low throughout, but I guess that's not related to high charge on the variable cap, which would be several kV. I won't be using the K2 on this loop antenna again, just in case. Pity, because it's great to get a 57 reports working into Austria and Russia and 59 into Florida, running 50W into a diminutive 1m diameter loop sitting on my picnic table :) I'll report on the patient after the surgery... 73, John VK7JB -- View this message in context: http://elecraft.365791.n2.nabble.com/K2-100-Hi-Curr-and-loss-of-power-control-help-de-VK7JB-tp6485865p6486856.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
