As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK / DECLARED EMERGENCY. PASSING 10,000 MSL CREW REPORTED STRONG BURNING SMELL IN CABIN. SMELL INTENSIFIED AND REMAINED UNTIL AFTER LANDING AND SHUT DOWN. FOUND CABIN PRESSURE CONTROLLER OVERHEATING. REMOVED AND REPLACED PRESSURE CONTROLLER PER MM.