[Elecraft] K3 high pitched tone and noise when keying the mic

[Paul Taenzer]

I recently developed a high pitched tone and seemingly random noise when
keying the mic with either PTT or VOX

The K3 has been set up and running brilliantly (as one would expect) for 5
years with no changes to the set up recently.

The noise goes away when the mic gain is set to zero. Changing from the
Yamaha CM500 to a random computer headset made no difference.

The mic is connected via the rear panel connector.

I'd be grateful for troubleshooting ideas.

73s

de Paul
VA3LX

Paul Taenzer
ptaenzer at gmail.com
613-385-1226