What was found
DURING CRUISE FLIGHT NR 2, DU-870, DISPLAY FLICKERED THEN WENT BLANK. SWITCHED INFORMATION TO NR 3, DU-870 DISPLAY, SHORTLY AFTER THIS NR 3 DISPLAY UNIT FLICKERED THEN WENT BLANK ALSO. AFTER LANDING, TROUBLESHOT BOTH DISPLAYS, BY INSPECTING WIRE HARNESSES, AND CHECKING FOR POWER AND GROUNDS. NO DEFECTS NOTED OF THE WIRING. BOTH DISPLAYS FAILED INTERNALLY. REPLACED BOTH UNITS WITH REPAIRED AND UPGRADED MOD STATUS UNITS.