[Elecraft] Audio leakage

[John]

When transmitting, there is leakage from the microphone to the speaker 
(e.g., feedback).
This may be operator error (having inadvertantly pushed the wrong button at 
some point during operation) or a problem with the radio and affiliated 
firmware.  I have atempted to read through the asorted notes, digests and 
manual to no avail.  'MIC+LIN' is off
Regardless of cause, how can this feedback between microphone and speaker 
be eliminated?
John Kountz. KE6GFF/T6EE
sn: 03271