When the KPA500 first came out, there were lots of complaints about hum. This made it difficult for Elecraft Support to differentiate between normal hum, which I can barely hear, to the obnoxiously loud hum of a misaligned transformer. I finally called support so they could hear the hum of my KPA500, which was in the obnoxious category.
Take a breath, you can fix this. Tweaking the bolt torque, and slightly moving the transformer, requires only removing the cover. If you don't own and can't borrow a torque wrench, given your investment--buy one. A small, inexpensive one will do the trick as the torque is quite low. 73 Eric WD6DBM On Mon, Oct 19, 2020, 5:00 PM Jim Spikes N4KH <jimn...@gmail.com> wrote: > Looking for details from anyone who resolved issues with excessive > transformer hum during transmit on a KPA-500. > > > > I have a hum mitigation application note sent from Elecraft tech support. > But the procedure recommended is pretty involved - removing front/side > panels, un-plugging connections, removing the transformer, changing > positions of the rubber discs, and putting it back together. Possibly more > than once, depending on the results. > > > > There is a risk of breaking something, and I'm not sure its going to solve > the problem if I'm successful. This is a new out of the box KPA500 kit. > > > > If anybody has any lessons learned I would appreciate hearing them. > > > > Jim, N4KH > > ______________________________________________________________ > 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 > Message delivered to norrislawfi...@gmail.com > ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
