As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JUST AFTER DEPARTURE THE CREW REPORTED THAT THE CWP AVIONICS SMOKE WARNING ACTIVATED INTERMITTENTLY. THERE WAS NO OBSERVATION OF SMOKE OR SMELL OF FUMES. FA REPORTED A BURNING SMELL. THE FLIGHT RETURNED TO DTW AND LANDED WITHOUT FURTHER INCIDENT. AN EMERGENCY WAS DECLARED. REMOVED AND REPLACED AVIONICS SMOKE DETECTOR IAW AMM 26-13-05 NO BURNING SMELL NOTED. ALL CHECKS GOOD, P/N ON OFF 72-111211-00 S/N ON A5305 S/N OFF B5488.