That's what happened to my samsung LE40B530P7 tv- twice. First time under 1 year warranty so got it free, second after 2 years. Samsung didn't want to know the second time so they put me onto an outside contractor who wanted £60 just to come out to tell me the pcb needed replacing. Went on ebay and got one for £30. Fitted myself and now as good as new. Good luck but don't waste your time with Samsung help line as help line is a contradiction in terms.
Michael
October 2011