Samsung UN46F5000AF WON'T TURN ON.iF i LEAVE IT UNPLGGED FOR AN HOUR PLUG IT IN IT WILL SOME TIMES COME ON

The backlight is most likely failing on this set.

The main board would be susoect next if the power supply has already been replaced.

Are there lights that come on but nothing showing up on the screen? More info needed.
Can you hear the laptop running?
Take out battery but leave the power supply plugged in and then try to startup.
If the lights come on and still no image on screen hold the power button down for 1 minute not letting up with the battery out, the power unplgged from the laptop. After that minute plug in the power cable and try to start.

Switch off the TV from remote, then switch off the on/off button on the TV, remove the plug pin from the power outlet. Cool off for 48 hours and then retry. If nothing works, better refer it to a qualified service technician.

Try turning it off and on or pull the plug out and leave it an hour

Take the battery off. Leave the cover off. Put the phone in a bag of rice. Make sure it's completely surrounded by rice. Leave for at least a day. Two would be better. Clean the phone off, reinsert the battery, plug it in to power, and try it. If it still won't power on, getting it wet with the battery in has shorted out components and blown them. If it does work, all's well.

Good luck!

It sounds well flooded, remove the spark plug, with the kill switch to off, crank the engine five or six times to evacuate any excess fuel in the cylinder, leave the machine for an hour or so, re fit the plug and attempt starting with no choke.

Hello,
Please try to power cycle your Samsung BlackJack. Please remove the backlid and remove the battery. Now plug in the charger and after that the battery. Now leave this phone for approx 1 hour. Now try to turn it on.
I hope this helps but if does not even help you need to contact Samsung for a repair.
Please do rate my solution.
Regards, Rashid.

try pressing the menu button and the play button at the same time

Pull out the plug for the TV and leave it out for one hour at least.  Plug it back in and it should be ok.  It will re set itself.