hi i have a acer 5755 the usb3 connector was shorted i and pcb board few was burned but i correct this problem and device turned on (before was not truned on) now when i power on the laptop light come for lcd but no character on it
i tried change lcd but not help
i programed bios and ec
i change i/o
i replace the flat cabe with new one
i heated the gpu
when i plug the external monitor display is fine

but not help and now led only light and now character


what signal or voltage must come who lcd show character ?////////???