Question Laptop backlight turns off when charger unplugged - tuns back on when plugged in again


Mar 26, 2018
I have searched for this already on here and seen many posts with fixes by webworkings but none of them have worked for me so here goes...

Asus X555YA laptop running Windows 10 - belongs to a friend and they asked me to have a look a the screen issue - which is that the screen backlight turns off when power cable is unplugged, but comes back on when it is plugged in again. The laptop doesn't turn off and when I plug it in again I can see the notification saying the laptop is charging as the screen comes back on. I can also see the screen contents if I shine a torch on the screen when the backlight is off so I know it's there. Also happens in the BIOS.

So far I have tried all these with no change in behaviour:
  • Install latest windows updates
  • Installed latest AMD Radeon R5 GPU driver
  • Uninstall and reinstall graphics driver
  • Set power settings to default
  • Used keyboard shortcut to make screen brighter when unplugged (I can see it is on max. using my torch)
  • Create a new power setting profile to never turn of screens
  • Updated BIOS
  • Checked the Refresh rate - it's fixed to 60Hz as that's the only frequency that graphics card supports
  • There's no Intel HD chipset so I can't modify settings for that which was a common fix for others

Are there and other software fixes I can try before checking cables/potentially replacing the LCD unit? It seems like a power shortage or something?

Thanks in advance!