I had a similar problem with my Samsung LE40A856S1MXXU it would switch itself off and on at random. I called Samsung and they arranged to have it collected and repaired free of charge, that was November 2012. Now April 2013 the problem has returned. This time around Samsung are saying the TV is out of warranty and that I would have to organise and pay for any repairs out of my own pocket.

Terry, April 2013

not exactly sure, but thats what happened to mines. first the tv would make cracking and popping sounds. then the tv would take forever to tur on and then finally it stopped turning on. i fixed it myself cause the repair man said it would cost over 400 bucks to fix it when in reality i fixed it for under $25. i used a video on youtube to help me fix it. if your tv is not under warranty, try doing it yourself and save some money. heres the link to the youtube video: http://www.youtube.com/watch?v=EbGiXqBAvvo
If you need a technician service , you can visit this website http://tvrepairjax.com

neil, April 2013