[Elecraft] microphone issue on K3

[sp5apw]

Today, during mobile operation on battery powered K3 I experienced a
modulation problem. When I started to transmit my signal became over
modulated (even mic gain was low) and I didn't hear my voice in headphones
(I have switched on voice monitoring) but heard noise. Even in case when I
stopped to talk (but PTT was pushed) the signal was still over modulated by
noise. Only in case when PTT was pushed by I didn't started to talk the
transmission wasn't modulated. But as soon as I started to talk it started
to be transmit noise. On the beginning I taught that my mic was
out-of-order but I tried to use computer mic connected to rear mic socket
(of course I changed configuration :) to rear mic) but the problem appeared
again. So, it means that this is not a mic issue but a damage of the rig.
May somebody advise what to do? Sorry for my poor English.
Jacek SP5APW