...Help and ideas, really... from someone who has something similar.

Some time ago I got an ASUS Zenbook 15" HD Touchscreen, Core I7, WIN8.1, two SSDs, goes like the clappers and everything nce...
- except...

I cannot get a constant brightness on the screen. It sometimes goes to a dimly lit display - as if you were running on battery save mode or something.
It has settings that I have adjusted to supposedly show the same brightness all the time, but it still changes. It does a few minutes bright, and then
half a minute or so dim.

An on-line search of the "problem" told me nothing I could put my finger on. Does anybody get the same happening? Have you found a solution?

Model: ASUS U500VZ

Ta, Am.