My screen close down from top to bottom and lives a horizontal line rite @ the center of the screen,,,,, Which component is mostly faulty in here ? and what kind a component is this ..?
It may be due to an Integrated Circuit [IC] fault. Your TV has lost its vertical sweep, and the is why you see a norizontal bright line across the center of the screen. All TVs has bot Hotizontal and Vertical Sweep to spread picture on the screen. When Vertical sweep fails, you will see a horizontal line, and when horizontal sweep fails you will see a vertical line at the middle of the screen.
n your TV, most likley the vertical Ic is faulty. This is a common phenomena in almopst all telivisions. The said IC is diretly soldered into the circuit board inside your TV. To replace it you have to open your TV. Take all precautions before opening the back cover of your TV. You are going to work with an electrical equipment, and keep it in mind always. After opening the back cover, just locate where the Vertical Output Ic is. It will be normally screwed to a heatsink plate, inorder to radiate heat from it while working. You can locate it by the following method. Different TV circuits has different positions to this Ic. Just look on the Deflection Yoke [the coil fitted on the neck of picture tube]. From there four wires will go to the main printed circuit board. Out of which two of them will be thick, and other two will be thin. The two thin wires are the carriers of vertical sweep from main board to deflection yoke. Follow the the two thin wires. You will see it to be pluged into one point at the printed circuit board. Just upside down the printed circuit board, after pulling it outwards, not disturbing any of the wirings, and look through the circuit track, to which point the tracks goes to. Somewhere near to it you can locate the above said IC.
Just take the main input votage to that IC. It will be normally 18v to 35VDC. You must have multimeter to measure this voltage. If the voltage is there, look for any loose solderings over there to the legs of that IC. If there is any soldering loose, the IC will not work properly, and vertical sweep loss will be the result. If there is proper voltage check the voltage at the output pin of that Ic. It should be almost half the voltage of the supply voltage. If it is not there, make sure that the IC has damaged.
Resolder it out from the board, and go for a same type and number. Replacing it will solve the problem. Normally vertical output ICs are not very cosltly. Here in India, all types of vertical Ics will have a price rate between 80 to150 Indian rupees, that is upto four American Dollars. Ok.