What was found
TWO HOURS INTO ETOPS FLIGHT, CAPTAIN`S FMC/CDU SCREEN WENT BLANK FOR 10 TO 15 SECONDS FOLLOWED BY A BITE TEST MESSAGE ON THE SCREEN. OTHER INDICATIONS WERE ILLUMINATION OF ALL CAPTAINS FMC/CDU ALERT LIGHTS (CALL ECT). NO OTHER ANOMALIES NOTED. NO MAP OR VTK FLAGS, LNAV, VNAV REMAINED ENGAGED. ACFT GROUNDED. PERFORMED CDU BITE CHECK ON CAPTAINS FMC/CDU IAW AMM TASK 34-61/801. NO INFLIGHT FAULTS. PERFORMED FMC CDU INSTALLATION TEST IAW AMM 34-61-01-400-802. TEST OPS CK OK. NO HISTORY PAST 30 DAYS. ACFT OK FOR SVC.