Sounds like that backlight drops out. Take a flashlight and look for a picture, it may be there without backlight. Its hard to see but look for letters or a menu (push menu) .
Many products have bad capacitors, if you lose backlight this can be the cause. Open it up and look for bulged caps, they look like this:
let me know if I can be of further assitance

Hello,

you can get this fix by you

- TURN THE TV OFF AT THE MAINS. This will reset it to default. Wait 1 minute at least.

- TURN TV ON. Ensure you have sound so you know the video/audio feed is OK.

- PRESS THE TIMER BUTTON ON THE REMOTE
you should now have picture or at least response from the screen indicating what channel it is on.

if that do not work
More than likely this will be down to your Y Sustain board has gone faulty, when the back is off your TV it is on the left hand side and will probably have a fuse that has blown, replacing the fuse will not solve the problem as it is the IMP under the heatsink that has gone faulty.
You should get the part number of the board and Google or Ebay for a replacement.
Hope this helps