Television has sound can change channels....but has no picture just a thin horizontal line in middle of screen

Hello
The vertical sweep section of your TV is faulty. It may be either to a loose solder points at somewhere in that section of to the fault with the vertical output IC. Check all the solder points on the vertical output section of your TV. It is best to resolder most of the suspected soldering points, by applying a little more solder, without making any solder bridge short in between adjecent solder terminals. If this does not help you, replace the vertical output IC with same type and number. OK.