Samsung 26 R74BDX All that is visible on switching on is continuous vertical grid right accross the screen. No proper picture at all. same using dvd or games etc.

Hello,

All Plasma and LCD TV have boards that control vertical and horizontal output to their respective areas. They are connected to the screen by ribbon cables. If one of these boards fails all together, has a failed chip, a bad connection, or a bad ground somewhere it will result in a black line in the area of that board. A bad ribbon cable connection on the bottom will result in a vertical black bar though the screen. Many times resetting the connection will fix it, if the ribbon cable has been nicked there could be a severed connection. They an sometimes be fixed, but it is a pain. An yes I have done it, but the bar is gone. The same will happen if the chip that outputs to that area opens. The connectors are the first place to look paying close attention to the cable, they are extremely delicate so great care must be taken if you decide to tinker with em, the usually have lift locks that release them, but it is very easy to wreck em.
Good luck in solving the problem.