A laptop's inverter board powers the backlight bulb in your laptop screen. The inverter board converts low voltage DC power supplied by the motherboard to high voltage AC power needed for the backlight lamp inside of the LCD screen. Sometimes these are known to fail.
Basic Symptoms of a Failed Inverter Board:
When you turn on the laptop, the screen lights up for a short period of time and then goes dark. Your laptop turns on but the screen remains dark all the time. You still can see a very dim image outline.
The laptop screen works fine for hours or even days, but sometimes it goes very dark as mentioned above. When you restart the laptop, the screen works fine again.
The issues above don't happen when connected to an external monitor.
Note: if you cannot see an image on the screen at all, mostly likely the issue is not with the inverter.
In some cases you may hear a buzzing noise coming from the area where the inverter board is located (on the bottom part of the display.)
The inverter board can be tested by using a laptop screen backlight.
If the inverter board works, then more than likely the LCD screen has gone bad.
Laptop Screen Replacement
Screens are ordered from Ebay top-sellers that back their screens with warranties