This issue just popped up on here a couple of weeks ago. Here is a copy of that exchange which might address your problem too:
posted by calman71 on Nov 01, 2008
screen lights up white, no picture
posted on Nov 03, 2008
The only thing to try would be to locate the contrast knob next to the screen (near lower right of screen) and turn it to see if the picture gets better. I have the Mk1 which has a green screen, but I find that one is only visible when the contrast knob is pretty much exactly on center.
If that doesn't do it, I would begin to suspect a loose connection behind the LCD screen. You could probably remove the cover and locate the connector yourself, but depending on how old your 2488 is doing so might effect the warranty.
Comment by calman71, posted on Nov 06, 2008
Turns out to be loose wires.Thank you for helping ,