Jim, You definitely need to contact Elecraft support. I had exactly the same problem with a K3S I built recently and the KPA3A was bad. Elecraft replaced it and all is well now. Lou W2ROW -- View this message in context: http://elecraft.365791.n2.nabble.com/RF-in-Microphone-tp7628511p7628542.html Sent from the Elecraft mailing list archive at Nabble.com.