What was found
SUPPLEMENTAL PACK #2 HAS A VERY UNUSUAL NOISE AND WAS FILLING THE CABIN WITH A BURNING TYPE ODOR-C/A-VERIFIED NOISE COMING FROM PACK #2 PERFORMED ENGINE RUN WITH CREW INDICATING PACK #1 NO SMELL NOTED. DEFERRED PACK #2 SYSTEM AUTH 030559D-C REF 21-30. COMPLIED WITH EO EM-2100-048. REMOVED AND REPLACED RH ACM AND RH DUAL HEAT EXCHANGER. PERFORMED OPERATIONAL TEST OF COOLING PACK SYSTEM IAW EMB 145 AMM 21-51-00. OPS/LEAK TEST GOOD. NO DEFECTS NOTED. MEL ITEM RESTORED.