Even the 'normal' hum was too much my tastes. My KPA500 is now on the floor, under the desk with a remote digital readout on the desk.
John K7FD > On Oct 19, 2020, at 6:25 PM, Eric Norris <norrislawfi...@gmail.com> wrote: > > 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 macymonk...@charter.net ______________________________________________________________ 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
