The laptop screen goes black for no reason. The laptop starts properly and the screen works properly for some time, but later it just goes black. After you restart the laptop, the screen goes black after some time again.
1. Screen inverter failure.
2. Screen backlight failure.
Possible troubleshooting steps and repair solution:
Most likely this problem is related to the screen inverter failure. The inverter board works as a power supply for the backlight lamp. When the inverter fails, the screen goes dark. You still can see a very faint image on the screen but it’s very dark. Try replacing the inverter board first. It’s located inside the display panel below the LCD screen.
If a new inverter doesn’t fix the problem and the screen still goes dark after some time, most likely you have a faulty backlight lamp inside the LCD screen. If that’s the case, you’ll have to replace the screen. It’s possible to replace just the backlight lamp but it’s not easy and should be done only by an experienced technician.
When inverter or backlight lamp fails, you still should be able to use the laptop with video on the external monitor.