As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DUURING CLIMB AROUND 9000FT LOUD POP HEARD THEN CABIN STARTED TO DEPRESSURIZE...NOTE PACK 1 CURRENTLY ON MEL. REF LP 289288 SEQ 1 FOUND BLOWN DUCT ON #2 HEAT EXCHANGER. R&R'D DUCT A/C PRESSURIZED CHECK GOOD. #2 PACK OPS CHECK GOOD. OK FOR SERVICE.