[Elecraft] K3: DVR open ground problem

[Matt Zilmer]

K3 #24 was upgraded to include the DVR earlier this year.  It worked
fine while testing just after installation and configuring.

I used the DVR a few times for contesting, but not much recently.  I
noticed recently that any recording I make has the hum of an open mic
(ground or shield?) superimposed on the voice signal.  Seems like
there might be a bad connection, but looking at the schematic this
makes no sense - to have this problem with the DVR only.  The audio
straight  from the mic should have this problem as well.  The mic
audio is fine though.

Anyone have experience with a problem like this?  I will do the usual
- uninstalling, re-installing (reseating the connector), but since the
mic signal at the connector is digital I don't think this will help.

All ideas appreciated.

73,
matt W6NIA
K3 #24
K2 #2810