As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 FMC SCREEN STROBING BRIGHT TO DIM WHEN DISPLAY IS DIMMED. ACFT GROUNDED. PERFORMED FIM 34-61, TASK 803 WITH VARYING DIMMING RHEOSTAT SETTINGS, VARYING LIGHT INTENSITY ON CDU LIGHT SENSORS PRODUCED NO DISCREPANCIES. INTERMITTENT FAULT. NO HISTORY LAST 90 DAYS. GROUND VERIFIICATION TESTED GOOD.