No picture or just one line across scr...

Could be a loose connection on the printed circuit board in the Vertical deflection circuit.
You would have to have a qualified technician to repair this problem.
A intermittent connection in the circuit described can cause a horizonal line across the screen.
You have to be careful and not leave the TV on for a period of time with a bright line, as it can actually burn a line on the CRT screens, which is permanent.