What was found
CLIMBING THROUGH FL380 EXPERIENCED POWER INTERUPTION WITH NO APPARENT CAUSE. LOST BOTH A/P'S AND ATS WITH MAP FAIL ALERT ON BOTH SIDES AND IRS/NAV X'D OUT ON CAPT'S PFD. CAPT'S MCDU DISPLAY REVERTED TO ACARS - APPLICATION MENU. F/O SELECTED STBY OPERATION. INITIALLY F/O MCDU WOULD NOT TUNE A VOR FREQUENCY. LATER IN DESCENT F/O NAV/RAD TUNED OK. AP1 AND AP2 RETURNED TO NORMAL BUT ATS REMAINED INOP IN 1 AND 2 POSITIONS. INTERROGATED DEU'S 1, 2, & 3. FAULT HISTORY SHOWED FMC 1 FAILURE. REMOVED AND REPLACED FMC 1. AUTOTHROTTLES, FCC'S ALL OPS CHECK NORM PER M/M. RETURNED TO SERVICE.