[Elecraft] [K3] front mic not working after subRx install

[Mike Scott]

I installed the second receiver in my K3 and at the same time made the
prescribed audio and line out modifications.

After checking out the receiver my microphone is now dead using the front
panel. Rear connection works okay. I have been using the front panel
microphone connector without a hitch up until the time I went off line to
make the above modifications. 

So has this happened to anyone else and is there something obvious before I
start taking covers off? 

One thing to note, I did have a problem with the SubRx install. The Sub-In
and Sub-Out board connections to the SubRx are very difficult to tell when
they are mated correctly as most of the pins are not visible. I apparently
ended up with an improper mating and smoked the sub-out board. A quick call
to Elecraft identified the problem and a new sub-out board put me on the air
after a very careful inspection of the connectors this time. I am wondering
if the sub-out is the only thing that I smoked now. The microphone-audio
path seems quite remote from all this activity but I don't know what sneak
paths I might have created with a misconnected sub-out connection.

I checked microphone gain (it is set at 30 with front panel-high, no bias),
just as it was before this problem arose. Those mic settings work well for
the rear connector using the same microphone. I use one of those Kenwood
adapters to audio plugs that came with a microphone and the microphone has a
dynamic element.

Mike Scott - AE6WA
Tarzana, CA (DM04 / near LA)
K3-100 #508/ KX1  #1311