screen dimming issue

OK, so i know there are a lot of these posts all over the internet and I've searched and searched to no avail, and I'm starting to get frustrated. So I have a Samsung 470R and I can plug it in and turn the power on and i have a bright screen and working adjustment, and if I unplug it, it is still bright and i can still adjust it. Not a big problem when, I'm home and or near a power source, but I'm usually not, so the real issue begins. If I have it unplugged and just using battery power when i power it on, it starts with a dim screen, and I can't adjust the brightness at all with any method i have read. If I plug my power cord back in while it is still on the screen stays dim until i power it off and power it back on with the power cord attached. Weird right? So, since I really don't want the same methods I have already tried I will list a few of them for you: power options, changing plugged and unplugged default settings, graphics settings to maximum performance, disabling and uninstalling display driver, which is the Intel HD 4000 v. 10.17.10.4229, and as far as I can tell there is no easy way to swap and test a battery, so I never tried that, but the battery does run good and for a long time. Nobody else seems to have posted this exact same problem and it has been very difficult, and very frustrating, so please, if you have any input that may help, it would be very much appreciated.

Just a couple of thoughts...

Whatever the issue is, it will not be the battery. That can ruled out. This sounds like a software/driver issue to me. Have you tried a restart when on battery to see if the rebooted state has the brightness working ?

I'm not familiar with your laptop but have you looked in 'Control Panel' and looked under 'Intel'. Change control panel view to icons to see this (top right of screen). Have a look at what options are available, these are the settings I use... you may have similar. When you mentioned 'Power Options' I'm not sure if you meant the Windows options from the system tray (battery icon) or these.

Ok, so I have tried turning my laptop on and off in all manners of plugged and unplugged, restarting, sleeping, screen saver, and shut off and turn on, if I turn it off and i try to turn it back on with it unplugged i get a dim screen and my Fn key dimming doesn't even show up i have to physically go to the icon tray, right click the battery, and click change screen brightness where I can slide the bar from that power options screen but it does not change my brightness at all. It's always in the same position as default setting should be, but the screen just won't get bright. I have looked at the intel graphics properties settings too and everything seems to be set up fine and to maximum performance. No matter which driver I install I get the same issue so unless there is a different driver I need to locate and change, I think we can safely rule out a driver issue. Like I said I have tried most of the simple and common user error issues and driver issues, but that doesn't seem to be the case with this one. I don't know what other information I can post to make this any easier too so if you ask me a question I will try to get you the best answer I can. And thanks in advance for your help.

I can't really think of anything more specific you could try on this.

Has this worked OK in the past and suddenly just stopped working ?
Also, is the installed operating system and so on all as it came from Samsung or have you reinstalled W8.1 in some way ?

Both my Dell laptop and an old Acer laptop have a small manufacturer specific application that is installed to enable various functions such as volume/brightness etc. I'm wondering if you are missing something like that if you have reinstalled the operating system.

Did it ever work as you expected?

I agree, it is not the battery but I note it is typical for notebooks to decrease display brightness when on battery to increase battery runtime. And I note in your manual on page 58, it says,

The screen brightness is automatically set to the brightest
level when AC power is connected and the brightness is
automatically set dimmer when the computer runs on battery
power to extend the battery use time.

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