Maybe a little anorak, but here goes...Probably the backlight not coming on, the inverter gets fed with 24v dc from the power supply, it generates a stupidly high ac voltage for the cfl back lights, the back lights are switched on via a 5v coming from the main processor. So going onto the inverter you should have 24v (or 12v) dc and the "on" 5v from the processor. Usually the board will have printing near the plug that tells you the voltage.. You can put 5v on the pin to fire the screen up (you'll probably see a dark stripe across it as one of the back lights is probably gone) that's if you have the supply voltage coming from the psu...(at your own risk! I have done this) Look for capacitors bulging on top, that's quite a common one. The inverter in LCD TV knows how much current is being drawn by the back lights, it then knows if there's a cfl out.. You can hang a scope near the inverter output and pick up the kv ac waveform. Its at about 30khz If you see it come up then go (or the 5v come up and go) then your backlight is faulty only way to fix this is new/replacement screen (eBay)
Or probably time for a new tv!
If its led backlit, then who knows..???
Some of the newer samsungs have one board for the psu and inverter, you'd need a circuit diagram, if you could find one!
(older ones had psu, signals and inverter boards.)
you could search eBay for the inverter board (part number is on the board bn.....) and give it a go, it might be the inverter faulty.
imo. Screen
hope this helps.