What was found
CLIMBING THROUGH FL220 WE HAD RT FMC FAIL FOLLOWED BY THE LEFT. AUTOPILOT AS THE ONLY EICAS MESSAGE. A/C REVERTED TO V/S WITH AN AMBER LINE THROUGH V/S. ACCOMPLISHED FIM 34-61-813 AND SUSPECT RT FMC FAILURE. ACCOMPLISHED FMC BITE PER FIM 34-61-822 AND LEFT FMC, OK FOR SERVICE. ALSO ACCOMPLISHED FMC OPS OF LT FMC OPEN AMM 34-61-00 AND OK. NAV LOADED DEFER AT FMC INOP PER MEL 34-61-01-01A CAT C MDDR 133879. CLEANED CDU INLET SCREEN, ACTIVATED PREVIOUS DATABASE, PERFORMED SYSTEM TEST IAW AMM 34-61-00-715-001-003, NO DEFECTS NOTED. THIS CLEARS MDDR 133879.