What was found
LEVEL 1, TR 3 FAIL ALERT. AT FLIGHT LVL 310, LEVEL 1 FIRE DET 2 FAULT. DISPLAYED 4,5,6 AND MCDU 2 ON F/O SIDE FAILING MULTIPLE TIMES ACFT POSITION INVALID IN FLIGHT DISPLAYED ON MCDU. DISPLAY 4 SHOWED INTERMITTENT RED X. MCDU 2 FAIL. R & R BAT CHARGER TRANSFORMER RELAY (R2-18) AND CKS NORMAL IAW FIM 24-31-01 AND AMM 24-25-03, PB201. RECYCLED C/BS AND TEST PASSED ON FIRE DET 2 FAULT. ALL OTHER CONDITIONS BACK TO NORMAL. ACFT OK FOR SERVICE.