Chosen Solution
What is controlling the power sensor of the LCD screen? Watch the video: https://youtu.be/Au-ejshx3PQ
Hi @pjenssen , There seems to be a problem with the backlight power to the display panel. Not sure but looking at the ifixit Toshiba Satellite L55t-B5271 Screen Replacement guide, there seems to be only one cable (LVDS cable) going to the screen from the motherboard so the backlight power supply must be in it as well as the video information. It may be that the cable is damaged as it passes through the hinge to get from the motherboard to the screen. If the cable is OK it may be a loose cable connection on the back of the screen panel. Here’s a link to a supplier of the part if it is damaged and needs to be replaced. It is shown only to give you an idea of the cost of the part. There are other suppliers online that may suit you better. Just search for Toshiba Satellite L55t-B5271 video cable to get results
