Full marks for your investigation, Craig. Sounds like the winding tension was set too high and the core bit through the enamel. That will be covered by the Elecraft guarantee.
David G3UNA ----- Original Message ----- From: "Craig" <[email protected]> To: <[email protected]> Sent: Sunday, July 05, 2009 1:05 AM Subject: [Elecraft] K3 3051 audio buzz in chassis on SSB > > 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:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ 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
