What was found
AIRCRAFT WAS GROUNDED: F/A REPORT A STRONG JET FUEL ODOR IN MID CABIN MOVING AFT THEN MOVING FORWARD. MAINTENANCE TROUBLESHOT CABIN ODOR IAW J/C 26L00021001 AND COULD NOT DUPLICATE FUEL ODOR IN CABIN DURING BLEED SYS ISOLATION DID DETECT AN ELECTRICAL ODOR IN MID CABIN, DETERMINED TO BE A BAD BALLAST AT ROW 22. REPLACED BALLAST IAW AMM 33-21-11. OPS CHECKED NORMAL. EXTERIOR INSPECTION OF ACFT REVEALED NO LEAKS FROM FUSELAGE, ENGINE OR APU. ACFT RETURNED TO SERVICE.