Dick, The KPA500 has a power supply switch on the rear panel adjacent to the socket for the power cord. When you press the OFF button on the front panel the control circuitry is still active. This permits software to remotely power up the amp. If you turn off that rear switch all power is removed from the amp; the same as pulling the plug from the wall socket.
Ken WA2LBI On Wed, Jun 27, 2018 at 13:38 Richard Wade <dickwade...@gmail.com> wrote: > Yesterday I heard a faint "hum" in my shack but all of my gear was off. It > sounded like possibly a fan running or power supply noise. I did a very > scientific test of the sound source by putting my ear to each piece of > equipment in my shack and soon found that the noise was coming from my > KPA500! The amplifier was off but was still connected to the shack ac > power. I then removed the power cord from the KPA500 and the noise > disappeared. Does anyone have any idea how this could happen? > > By way of further background, I have been dealing with QRN from a recently > installed solar system. I have traced the source of that noise to the > solar system by confirming that the QRN goes away when the solar system is > turned off while running my K3s on battery power. > > If I had to venture a guess, I would say that somehow the unpowered KPA500 > was picking up noise on the shack wiring. Very strange. Is that possible?? > > Dick, WM6G > -- Ken WA2LBI Sent from one of my mobile devices ______________________________________________________________ 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
