Originally Posted by
218ean
Just for completeness.
We had the same problem on one of our Fanuc 16i controls, intermittent but getting progressively worse.
Our problem was solved by unmounting and then re-seating the 3 daughter boards on the motherboard, inside the yellow box behind the screen. The screen had been messed about with a while ago to replace the backlight and it had never been screwed back up properly, hence there was a degree of flex about the whole assembly which had presumably loosened one of the connections.
The daughter boards are CNC motion, Graphics and main CPU.