What was found
LAX - FLAP POWER CAUTION LIGHT ILLUMINATED DURING APPROACH WHEN FLAPS FIRST SELECTED. STOPPED AT 1 DEGREE. WOULD NOT RESET PER E+A CHECKLIST. REMOVED AND REPLACED FCU IAW Q400 AMM TASK 27-51-01-000-801 AND INSTALLED IAW Q400 AMM TASK 27-51-01-400-801. REMOVED FPU IAW Q400 AMM TASK 27-52-01-000-801 AND INSTALLED IAW Q400 AMM TASK 27-52-01-400-801. PERFORMED FUNCTIONAL TEST OF THE FLAP CONTROL SYSTEM IAW Q400 AMM TASK 27-51-00-720-801. FPU AND FCU CHECKS OUT GOOD. NO FLAP POWER CAUTION ILLUMINATED. FPU REMOVED AND REPLACED PER MTX CONTROL.