What was found
AFTER APPROX 4.5 HOURS OF FLIGHT, THE RIGHT FMC DISPLAYED VTK, A/P WENT TO CWR. ALT HOLD. F/O'S NAV DISPLAY LOST TRACK INFO. WHEN WE WERE STARTING THE QRH PROCEDURES THE VTK WENT AWAY. AFCT GROUNDED. PERFORMED FIM 22-11 TASK 811, HAD FAULT MESSAGES 22-11071 AND 22-11822 FOR LEFT FMC. REMOVED NR 1 FMC COMPUTER IAW AMM 34-61-02-000-801. INSTALLED LT FMC COMPUTER IAW AMM 34-61-02-400-801. PERFORMED SOFTWARE LOAD IAW AMM 34-61-00-470-806 AND 34-61-00-800-801. PERFORMED FMC OPERATIONAL TEST IAW AMM 34-61-00-210-801. OPS TESTED GOOD AND DFCS REPLACEMENT TEST IAW AMM 22-11-00-740-815, DFCS TEST PASSED, GROUND VERIFICATION TEST PASSED.