As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, THE CREW REPORTED A LAV SMOKE MESSAGE ON EICAS WHILE CLIMBING THROUGH 500FT. THERE WERE NO VISIBLE SIGNS OF SMOKE AND NO ODOR REPORTED. THE AIRCRAFT RETURNED TO RDU AND LANDED WITHOUT INCIDENT. MAINTENANCE RAN EACH ENGINE AND PACK INDIVIDUALLY AND REPORTED NO SIGNS OF SMOKE AND THE LAVATORY SMOKE DETECTION SYSTEM WAS PLACED ON MEL. THE LAVATORY SMOKE DETECTION MEL WAS CLEARED IN SDF ON 7/2/2010. DURING TROUBLESHOOTING THE SMOKE DETECTOR CONTROL PANEL FAILED STEP 3 OF FIM TASK 26-14-00-810-802-A AND WAS REPLACED.