Backlight dims to half when unplugging

I recently reformatted my 1705 with XP again and now whenever i unplug it the backlight automatically reduces itself to half. It did not do that before. I'm using forceware 78.59 provided by dell with powermizer set at balanced. Anyone know whats causing this?

 

Control Panel > Mobile PC > Power Options > Change Plan Settings > On Battery > Adjust Display Brightness > Move slider all the way to the right.

 

Or hit Fn+F ?...where ? is the F1-F12 key that has a picture of the sun and an arrow up.

 

Dell normally has the up arrow as brightness up so hit fn+up arrow

 

Oops...they must have changed it from my last Dell machine then.

 

ya they are definately good for changing stuff up but my E1705 and Vostro 1700 have it with the arrows

 

You can set the brightness at different levels for battery mode and AC mode. Whenever you switch the power, it will switch to the default brightness level of that mode. Also when it is recover from sleep, it will return to the default brightness level of that power mode too. Check your BIOS for settings.

 

BUT... IN ORDER FOR YOU TO be able to set it over half brightness there is a bios setting that needs adjusting one for the max allowed brightness while on battery and one for the max allowed brightness while plugged in.. if this is set for half way even if you adjust it in windows it will only go up to as far as that bios setting allows for.. hold f2 while booting to get to your bios

 

That setting in BIOS is not for "max allowed brightness" but for "default brightness". I set the battery mode brightness to half and AC mode to max in BIOS. When I turn the brightness in battery mode using Fn-up to max then plug the AC adapter in, there is no change in brightness and it is indeed at the max level for AC mode too.

 

weird on my vostro i had i could not in vista adjust any higher then half brightness as long as that was set to 4...

 

Thanks for all the info. I don't have any options in control panel, must be in the BIOS. I"ll have to check it next time i reboot (about once or twice a month usually )