Outbound delay for no GW (Gross Weight) - no CG (Center of Gavity) computation for display on the #4 DU "Configuration" page, and no take-off "V" speeds on either ADI.
Problem appeared when power was changed from GPU to APU.
Had the crew try a FMC dump (power down) and reload...... same problem present. Maintenance joined crew at that point. Swapping display sources did not help. Placing the FMC's both on "1" or both on "2" was also a no-go.
After a call to MOCC and avionics line, the request was made to reset the fuel quantity breakers. After the fuel quantity C/B's were reset, all FMC computations and displays were present.
Apparently, fuel quantity values were not reaching the FMC's even though all quantities were present on the "Fuel" page.
Possibly a brain-fart of a databus transmitter in the Fuel Quantity Computer???? Just a guess at this point, but the aircraft went gear up and that's always a "good" thing.
It's similar to that one. Works much better than with the floppy disks. We are constantly loading different databases, especially on the 757 and A300. The 767, 747, and MD11s have worldwide storage capacity. For a while, folks were loading the wrong databases, like UP5-xxxx-xxx instead of UP1-xxxx-xxx, then they made us use Task Cards which forced you to read and review...not rocket science.