About a year ago I started getting a distorted screen on my laptop. I figured it was probably the video card, so I hooked up an external monitor and the artifacts still appeared, confirming it was the video card. The laptop had a dead battery and the screen cable was wearing out (the screen would distort when moving the hinges) so I decided to leave it alone for the time being.
Recently, I powered up the laptop to see if it was still running, but instead of getting artifacts the screen was simply blank, however I could tell it was booting fine. I replaced the motherboard and display cable, and it fixed the artifacts, but now the screen still appears black. At first I thought it was a blank screen, but if I shine a flashlight on it i can see that there is a picture. I did not have a chance to test this before replacing the motherboard, so I don't know if the screen was dim or blank before. My first thought was its the inverter, but this laptop appears to either not have one, or its built into the motherboard or screen. I even attempted to replace the screen, but the new screen had the exact same issue.
My other Idea is that the display cable could be faulty, since I purchased it used, but the picture doesn't look distorted at all with a flashlight. These cables are cheap so I may try another one to test it. I'd like to try flashing the BIOS, but it won't work without a functioning battery.
Any help I can get is greatly appreciated. Also I should add that the laptop works fine with an external screen, which is how I've been using using it for the past month.