Hardware'problem with screen brightness

[commm]

Hi!

Laptop : Acer Extensa 5620z, 4 years old

Problem : occasionally while using the laptop the brightness of the screen is getting lower, so that I see a picture but all in dark. Almost in every case I can restore the brightness by pressing Fn+F6. Sometimes it happens because of a light hit. I suspect that is somehow connected to keyboard.

Resolving : it seems like there is nothing to do with Windows, because in Dos I have the same problem

Your suggestions?

Thanks!

 

[WR2]

Hello commm;

Do you have any power saving mode set that might be dimming the screen?
Does the 'getting dim' process look pretty much the same if you use the reverse of the Fn+F6? might be Fn+F5 for dimmer?
That could be somewhat keyboard related.

It could be the backlight tube going bad, but that doesn't seem as likely.