Is the green light on (still indicationg power? Ist put your ear to it and switch on - hear any buzzing? Most like the HV Fluro Inverter for the lamps has an issue. For some the 2SC5707 may have gone - common.

I have had the same issue with my 700P, After tearing it apart, the culprit was found. the Inverter board (board model # 860-ALZ-M713-F / BF4250201G) tested poorly under load. The cause? The IC (U101) SEEMS to have overheated as the IC itself is scorched, and the board itself has darkened. What to do now? Unless you can find a replacement Inverter, I suggest you learn the pin-outs to the video converter, and place your screen on the pc case. You can use the correct voltage from your power supply to run the monitor. And then you will have a portable computer! Best of Luck!

I have MAG LT717s, it powers up and displays picture, but after couple seconds going black and no picture. What is wrong with it ?
This trouble maybe power supply or inverter boards is defective.
first you can test the voltage of the multr,and then check which part is defective.From Wisiny.com can find those parts
if you have any question,please let us know email:[email protected],we sincerely hope we can help you!
you can also check this boards whether suit you:
AI 0100B Lien Chang 860 ALZ GJ712D EH Power Supply Backlight Inverter

U could have a trojan or a worm or it broke srry man need more help tell me at [email protected]