Thank you for posting your question on Just Answer! I will be happy to help you with this problem.
Normally this is the signal board but go through check list below.
(Please click on high lighted words)
First push the menu button with the set s remote and if nothing comes up then
Friend this is a very common problem with LCD and also DLP within the power supply the capacitors
Start to fail and the way you can tell is to check them visually for swelling or expanding of the top.
It will be easy to see the bad caps will not be as flat on the top as the good ones, this is the problem,
Exchange them and you will be ok, Well good luck friend. And if it doesn't work make sure the power supply is sending 24v to the inverters when you turn the set on your meter should climb but won't reach 24v because unit will shut down and if so we ruled out the inverters or backlight I seen this problem also caused by the signal board it has a power on command missing and it looks like the power supply is bad but actually it's the signal board, it may be labeled on the board a active high or low 5v which sends the command to the power supply.
Good luck friend, and if unit works fine, feedback and a bonus will be appreciated
Capacitor pictures inverter pictures
Ok, if the caps are not swollen then it is the signal board, even look at caps on the signal bd
Good luck friend