What was found
CREW REPORTS: APU WILL NOT START. PER SAM RESET L41 & L42 CB'S NO HELP, APU S-DOWN REPORT SHOWS NO FLAME IGN UNIT (8030KM) AND FCU (8022KM). INOP'D APU PER MEL4910B, CREW PULLED AND COLLARED 'L41 & L42' ON PANEL 121VU USING DEF ER STICKERS, OPB GUS NOTIFIED. CREW COMPLIED WITH MEL4910B. :NEXT MAINT STATION DEN (FLT 0446-29). REPLACE DEFER STICKER WITH REGULAR CIRCUIT BREAKERS SAFETY COLLARS AT L41 & L42. FROM UNIMATIC (AMIS) PRINT DIS*07170-07171 WHICH CONTAINS MNL REF'S & PCN'S. PERFORM T-S & RPR OR REPLACE AS NEEDED. PLEASE INCLD FNDG'S IN ACP W-U. THX,SFOEPA MAKAIPO UNITEL X42379. :COLLARED BREAKERS, SUSPECT A WEAK FUEL CONTROL. APU STARTED TWO TIMES, & RAN NORMAL FOR 10 MIN WITH LOAD APPLIED (PACKS AND GEN.) REPLACED APU FUEL CONTROL UNIT.