Display brightness changes going from AC adapter unplugged to plugged in on Gateway NE51006u

Laserman

I have restored my Gateway NE51006u.
Battery was dead, bought new adapter, new battery.
Updated Bios to V2.14
Installed Windows 8.1 64 bit and upgraded to Windows 10 Home 64 bit.
Initial difficulty was that the system would BEEP when transitioning from plugged in to unplugged and back again once maximum charge was reached on the battery.
The fix for this ended up being installing Realtek R2.82 drivers and making it impossible for windows to update it. That made the annoying beep go away.
The screen though was also going off and on from plugged in to unplugged transition. fixed that by turning off adaptive screen brightness and setting screen brightness to 100% in both modes, using balanced power.

So. this is all good, but......
I notice a subtle change in brightness (darker) just prior to going to plugged in.
It doesn't seem to change when going to unplugged.
It's weird, my son can see it also.

Does anyone have any ideas for this?

Laserman

I seem to have found the fix for this.

The Gateway NE51006u uses on board Intel HD graphics.
The drivers from Acer/Gateway included Intel HD graphics for it.
There's an icon for it in the system tray.

Open properties to get the control panel.

Select Power.

Go to the On battery,
and set the Power Saving Technology to OFF!

Apply settings and the display will no longer change brightness when going from unplugged to plugged in or vice versa.