Hi Paul I had a similar problem which drove me nuts.
I pulled the K3 apart to try and find this problem and tightening every screw in the re-assembly process. The problem persisted however. This buzz was following my SSB modulation with perfect timing. I used a stethoscope and found that the buzz was coming from a small area where the SWR/power meter directional coupler was situated. The problem turned out to be one of the directional couplers transformers which was arcing to the ferrite core. At first sight the transformer looked perfect, however I could clearly hear the buzz in the stethoscope. I replaced the ferrite transformer and the buzz went away. When I examined this transformer, the arcing signs were very obvious under the enamel wire facing the core. The directional coupler transformers are very small and its a tricky job getting it back in place. Ideally this transformer should have better insulation, however there is not much room on the core for extra insulation. 73 Craig ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html