What was found
EQUIPMENT COOLING EICAS CAUTION F270 ON CLIMB. CAPT ND BLANK FOR 30", FO PFD FLICKERED ON CLIMB. MESSAGE BLANKED THEN LOST CAPT ND AND FO ND WAS INTERMITTENT. R & R PRINTED CIRCUIT ASSY IAW AMM 21-58-05/401 & IPC 21-58-55-01B. OPS CHK OK; SCREENS ARE NO LONGER FLICKERING ON CAPT & FO, ND. R & R FAN CHECK VALVE SLEEVES PER AMM 21-58-03/401 & IPC 21-58-03-05. OPS CHKD OK. NO LEAKS NOTED. R & R FAN CHECK VALVE ASSY IAW AMM 21-58-03/401 & IPC 21-58-03-05. OPS CHKD OK. NO LEAKS NOTED.