What was found
CLIMBING THROUGH 10,000 FT, A STRONG ODOR OF SMOKE IN THE CABIN AND COCKPIT. RETURNED TO DEPARTURE. AFTER LANDING THE NR 1 PACK OVERHEAT EICAS MESSAGE PRESENTED. REMOVED AND REPLACED THE NR 1 ACM IAW AMM 21-51-03. OPS AND LEAK CHECKED GOOD. COMPLIED WITH ETN-EM-72-034. REMOVED AND REPLACED THE LT DUAL HEAT EXCHANGER IAW AMM 21-51-02. OPS AND LEAK CHECKED GOOD. REMOVED AND REPLACED THE CONDENSER-MIXER IAW AMM 21-51-04. OPS CHECK AND LEAK CHECKED GOOD. WHILE PERFORMING ETN-EM-72-034 FOR THE ODOR EVENT, AT STEP 2, ITEM 10 - MAX POWER, LOUD GRINDING NOISE COULD BE HEARD FROM THE NR PACK FOR ABOUT 3-5 SECONDS, FOLLOWED BY THE ODOR IN THE COCKPIT FOR APROXIMATELY 30 SECONDS. PERFORMED INSPECTION OF THE RT PACK IAW AMM 21-51-00-200-801-A. NO DAMAGE FOUND. PERFORMED ETN-EM-72-034 AGAIN AND FOUND NO DISCREPANCIES. THE RT PACK IS OPERATING NORMALLY.