Hey, I have an Asus K555L notebook. The screen is not turning on, I use it with an external monitor through HDMI. It seem like windows recognises the screen but it's not working and it's not the back light. When I connect the 40 pin cable the board under the screen is getting hot on a spot. Is the cable dead, or is it the GPU? (btw sorry for my bad english 😃)
First, let me ask something to clear things up a bit, you say you don't use the attached display, instead you use an external monitor. Does the attached display itself not work? Or are you just using the external by choice?
I ask because if the attached display works (and just using the external monitor by choice) then you should be able to try using just the attached display to see if it works or not. This would tell you if the problem was the GPU or the external monitor/cable.
If the attached display was the reason why you use the external monitor, then I would try a different cable and different monitor to test it and see if it is one of those or the GPU. There is no way to tell without trying. Or you can take it to a local tech and they can do all the trials and work, but that would cost.
I use external monitor because the screen does not work. This laptop was my classmate's and I bought it. He said that the screen doesn't work. I ordered a new screen, but it does not work either, so that's why I use it with an external monitor.
I see. That is rather odd that even a new display won't work. Then I would suggest you try another external monitor, and another cable, to see if it is one of those. Those would be the cheapest to replace.
If neither of them resolves it, then you are looking at the GPU or even the motherboard.