What was found
APU FIRE INDICATION ON TAKEOFF AT 2000FT APU NOT RUNNING FOLLOW ED QRC APU FIRE BOTTLE WAS DISCHARGED. NO EVIDENCE OF A FIRE. SEE L/P 6705511 FOR REPLACEMENT OF APU FIRE BOTTLE. PERFORMED DETAILED INSPECTION AND WIRING CHKS OF APU FIRE DETECTION SYSTEM IAW 26-15-11 & 26-15-12. FOUND FAULT WITH APU CARGO FIRE CONTROL PANEL. REMOVED AND REPLACED FIRE APU CONTROL PANEL & RELAY K10374 IAW MM 26-22-03 AND WDM 26-15-11. OPS CHECK GOOD. ROTABLE PARTS CHANGE WAS INDICATED - TT # 1017399 SN OFF 1454 PANEL, APU/CARG OFF 19-3111-9-0018 1454 ON 19-3111-9-0018 1622