What was found
CAPT REPORTED AT 29K FT, GOT A LOUD SOUND AND FA SAID IT WAS COMING FROM SERVICE DOOR. CABIN PRESSURE BEGAN TO CLIMB AT 400 FPM. SOUND WENT AWAY AT 17K FT. AND PRESSURIZATION STARTED WORKING AGAIN. (FLIGHT 5321) CLEANED AND INSPECTED SERVICE DOOR SEAL IAW AMM 52-41-07-210-801 AND FOUND NO DEFECTS. LUBED SEAL AND PERFORMED LEAK CHECK IAW AMM 21-32-00-863-801 NO LEAKS NOTED AT DELTA-P 4.0