As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW OF FLT 1906 MKE-SDF, FOUND THEY HAD A STUCK CAPTAINS MIC-SWITCH IN THE 'ON' POSITION. THEY DECIDED TO TURNBACK TO MKE AND HAVE MX LOOK AT IT. THEY DEFERRED THE SWITCH BY DISABLING IT PER MEL GUIDELINES. THE SWITCH WAS LATER REPLACED. (M)