There is something short circuit occurs inside the PWBs. To make it sure which one is troublesome, a through check should be done. If you're sound in electronics, check this site.http://electronicshelponline.blogspot.com/
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This is a comon problem with the Samsung LCD HDTV on the Power Board.
You can repair or replace faulty parts on PS board.
When checking the capacitors, If they are slightly rounded on the top where the X is, the cap is defective. See the Youtube below.
Because the Samsung LNS4051D would not turn on and the power LED would blink 4 times and the relay would click and this would repeat again and again. I replaced power supply board parts CM806, 811, 812 & 817, all 1000 uf 10v capacitors, three had their tops bulged up slightly that I missed on initial visual inspection. After seeing the reports of problems with these caps on http://www.fixya.com/support/t1336881-will_not_turn_or_off , I replaced them with Radio Shack part 272-1032, 1000 uf, 35v. They are slightly bigger, but fit OK. TV is working fine now. Cost was 4 x $1.59 = $6.36 plus the time. I saved between $100 to 300 in the process of either replacing the board or getting the unit serviced. If you are not comfortable replacing components which means using a soldering iron, you can replace the power circuit board, available from www.Samsung.PartStore.com.
The t con board or the LCD panels is faulty. Can confirm only by replacing the Tcon board.
If you wish to know more about Tcon board problems and troubleshooting then check the following link.
http://electro-medical.blogspot.com/
Please check the flat cable connections between TCON board and the LCD panel. If this is ok, then it is either the TCON board or the LCD panel itself. Good luck.
