troublshoot to component level,it's cheaper!
Todd Hill posted an answer for this Samsung 46" Full Hd Led Lcd Slim 1080p Smart Internet Built-in Wifi Un46es6150:
"try lan first if connects wi fi module. have replaced many on these sets."
Todd Hill posted an answer for this Samsung Pn50a450 Pn50a450p1dxza 50" 720p Hd Plasma For Repair Or Parts:
"bad pdp panel"