As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A PASSENGER REPORTED A LOUD POP IN ROW 12C WITH A BURNING SMELL SOON AFTER. FLT DIVERTED TO RIC AND LANDED WITHOUT INCIDENT. RIC MX INSPECTED ACFT AND SUSPECTED NR 2 ACM TO BE THE SOURCE OF BURNING SMELL AND SMOKE. RIC MX PLACED NR2 PACK ON MEL (DEFERED) AND ACFT CONTINUED TO EWR WITHOUT ANY OTHER ISSUE. EWR MX R & R NR 2 ACM IAW AMM 21-51-03 WITH OPS SUCCESSFUL. ACFT WAS APPROVED FOR RETURN TO SERVICE.