There's 4 horizontal white tiny lines appear on screen to make the picture become 4 equal parts from top to bottom with many horizontal lines. My TV is Toshiba Lcd(40RV52U)

You have failure/weakening in the vertical section , the retrace lines appear due to the change in the freq.
Check out small value capacitors in this section. confirm by shorting parallel with the right polarity. Unless you are familiar with electronics please do not attempt unless with help. the fault is not very serious and could be attended with low expense.

Hi again,
I'm not sure why you closed chat session, however, we can sort out problem here as well.
Is it Toshiba 40RV52U lcd tv? Let me know.