Strange Issue - Super Dim Display In Bios and All OS's

CF31 - Windows 10/Linux/Bios

My screen is a little bright at night, even with the brightness is turned town all the way.

I went into my bios and changed the "LCD Brightness Mode" from "High Brightness" to normal brightness. I rebooted into W10 and Linux and noticed no change in the screen brightness.

The next day I went to use the computer and it was so dim that I could barely see it. I have to go into a dark room to use it at all.

I went back to bios and changed "Normal Brightness" back to "High Brightness". I've rebooted several times into Linux and W10, turned brightness up to 100% in both (I know it wasn't likely to work but I'm trying everything) and rebooted some more. Still really dim.

When first booting the system, the screen comes on very dim and stays that way no matter what.

I don't think its burned out because its mostly visible in a dark room but not really viewable in any brighter light condition.

The output to an external monitor works fine with normal brightness.

Any ideas?

Update: Booting with F9 to the battery re-calibration screen takes me to a normal brightness screen after I tell it to calibrate. Everything else is still super dim.

Thanks!

 

You can hold the power switch on for 10 sec to clear cmos. Hold it on until computer sharts up and shuts down

 

Unfortunately it didn't work. I did a battery re-calibration and several reboots. I held the switch for 10+ seconds many times but no improvement.

I've also reset the bios which by default comes with "High Brightness" as the default.

It's probably something dumb, but I can't find a reason that it boots very dim in bios and multiple OS's but regular/normal brightness when booting with F9?

 

Pop the memory cover and disconnect the cmos battery for 30 seconds. Be sure main battery is removed along with no external power.

 

That worked, thanks!