Fanuc 0i TD lathe control, LCD screen going blank.

Hi

I have two CNC lathes with the Fanuc 0i TD lathe control. I have a problem with the LCD screen on the control going blank. This is not the screen saver blanking the screen after 10 minutes of non use, this is when we are programming the machine or making offset changes with the keypad when the machine is running.

Nothing we do with key presses on the keypad will bring the screen back to life. The machine will continue to run, we can stop the program and re-start, but the screen is completely dead. The only way to get the screen back on again is to power cycle the NC.

Any one seen this and have a solution?

Thanks.