What was found
AIRCRAFT WAS GROUNDED. FLIGHT ATTENDANTS REPORTED ACRID AND STRONG PREVALENT ODOR IN CABIN WITH NR 1 ENGINE RUNNING/PACKS ON FOLLOWING HOOK UP TO START CART. AIRCRAFT NOT OK FOR FLIGHT. TROUBLESHOOTING PER TSM 49-00-00-810-846A AND ACCOMPLISHED J/C 26L00021001 DETERMINED APU WAS CAUSE OF CABIN ODOR. ALSO ACCOMPLISHED J/C 26L00021002 DUE TO APU OIL LEAKING. RAN BOTH ENGINES/PACKS WITHOUT APU LOAD CONTROL VALVE OPEN-COULD NOT DUPLICATE. OK FOR SERVICE. REPLACED APU PER J/C 26L31049003. LEAK AND OPERATIONS CHECK GOOD.