The capacitors on ALL Samsung TV's are notorious for burning out the capacitors on the power supply board. These can be replaced for very cheap if you know how to solder and can follow instructions on a youtube video. Replacement boards are about 150.00 IF you can find one depending on how old the unit is. Most repair shops will fix the issue for between 150-200 dollars but be aware that they are not replacing the board for that price nomatter what they tell you, they are simly going to replace the capacitors which you can do yourself or if you know somebody that's decent with electronics soldering they could do it for you.
You might also check with your local community college if they have an electronics program. Often these programs will do the repairs for around 50 bucks.