What was found
CAPTAIN REPORTED THAT DURING CRUISE BOTH PFD AND FIRST OFFICER ND WITHOUT INFORMATION AND ON BOTH SIDES FMA´S, ILS, HEADING, AND MONITOR LIGHTS FLASHED ALL THE TIME. CIRCUIT BREAKER B10-377 WAS RESET IAW MM 20-50-06 AND FAIL CONTINUE. THE SYMBOL GENERATORS WERE INTERCHANGED AND FAIL WAS DETECTED ON LT SIDE. THE SYMBOL GENERATORS WERE RETURNED TO THE ORIGINAL POSITION AND RT SYMBOL GENERATOR WAS COOLED WITH THE AIR CONDITIONING SYSTEM. DURING OVERNIGHT SERVICE EFIS SYSTEM WAS TESTED IAW MM 34-22-00, 34-22-06, 34-23-06 AND 34-22-10, ALL CORRECT.