10540
Practically you will take a heading and wait for the thing to come in then rectify the course but we were given a direct to the VOR which was 200 NM away after explaining the black screen problem.
It must have been about 170 NM from memory when the thing started coming alive.
I cannot remember precisely as I was throttling the first officer at the time who had caused the problem
not fun at night loosing the screens especially with all the STARS into Gatwick ahead.
Pace