As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT, FMC SCRATCHPAD SHOWED FOLLOWING MESSAGE "CHECK FMC POSITION FMC-FMC." RETURNED TO SEATTLE. ACFT GROUNDED. DIVERSION TIME: 39 MINUTES. CREW DEBRIEF REPORTS RT FMC POS SHIFT PAGE DATA BLANK AND WOULD NOT WORK IN VNAV. WHEN SWITCHED TO BOTH ON LEFT VNAV FUNCTIONED NORMAL. REPLACED RT FMC COMPUTER. RT FMC OPS AND SOFTWARE CONFIGURATION NORMAL. REF MM 34-61-02 AND 34-61-0. GROUND VERIFICATION SUCCESSFUL.