As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BURNING ODOR NOTICED IN CABIN BY CREW. TROUBLE SHOOTING IDENTIFIED PROBLEM AS OVERHEATING OF FWD E & E COMPARTMENT COOLING FAN. REPLACED FWD EXHAUST FAN AS PER MM 21-58-06. TESTED OKAY. SUSPECT DIRT BUILD-UP CAUSED FAN TO DRAG & REQUIRED MORE CURRENT TO OVERCOME FRICTION. LED TO OVERHEATED MOTOR.