Resolved Screen dims and brightens on its own while in use

res.ipsa

macrumors newbie
Original poster
Jul 12, 2015
26
7
San Diego, CA
Screen on my MacBook is adjusting the screen brightness while it is in use.

This is NOT the screen auto-dimming because it hasn't been touched. This is my screen getting brighter or dimming as I type this post. I can't seem to identify a pattern of when this is happening and it's driving me bananas!

I did a search but just found half lit screens. This is the whole screen dimming/brightening while in use.
 

motrek

macrumors 68020
Sep 14, 2012
2,437
162
Screen on my MacBook is adjusting the screen brightness while it is in use.

This is NOT the screen auto-dimming because it hasn't been touched. This is my screen getting brighter or dimming as I type this post. I can't seem to identify a pattern of when this is happening and it's driving me bananas!

I did a search but just found half lit screens. This is the whole screen dimming/brightening while in use.
Sounds like the power electronics for the screen backlight are on the fritz. I would record a video of the problem and then take it to an Apple Store (in case you can't reproduce the problem at the store).
 
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Significant1

macrumors 6502a
Dec 20, 2014
887
307
Is it with power-adapter connected?

There is a setting under power saving, whether it should dim the screen on batteri. So your power-adapter setup might have a loose connection and then your typing is causing it to momentarily run on batteri, due to vibration.

Try un plucking the power and see if it stops changing brightness while on batteri.
 

res.ipsa

macrumors newbie
Original poster
Jul 12, 2015
26
7
San Diego, CA
Is it with power-adapter connected?

There is a setting under power saving, whether it should dim the screen on batteri. So your power-adapter setup might have a loose connection and then your typing is causing it to momentarily run on batteri, due to vibration.

Try un plucking the power and see if it stops changing brightness while on batteri.
Significant1, thank you for the reply. It seems to be happening when I am on battery. It doesn't dim then go black (like it does when it is idle). It dims on and off sort of like an ebb and flow. It is so strange! I am waiting for it to happen again. Yesterday, I was working on it from about noon until 10pm, plugged in toward the end and it was fine. I didn't have it plugged in when I was home and it was dimming randomly while I was working on it. At first I thought it was because I was reading a long pdf but then it kept doing it even when I was actively clicking and typing. It's only 10 months old but it seems as though I may have to take it in... Ugh.
 

res.ipsa

macrumors newbie
Original poster
Jul 12, 2015
26
7
San Diego, CA
Is it with power-adapter connected?

There is a setting under power saving, whether it should dim the screen on batteri. So your power-adapter setup might have a loose connection and then your typing is causing it to momentarily run on batteri, due to vibration.

Try un plucking the power and see if it stops changing brightness while on batteri.
FIXED! I looked around the settings some more, found the problem and verified it when I found others with a similar issue. (I was searching "dimming" when I should have been searching "brightness" LOL) Apparently it automatically adjusts to light. So when I was in the library all day it was the same light and everything was fine. In my room it was adjusting to the pockets of light and shadow as I was moving around.

:apple: > System Preferences > Displays > Automatically adjust brightness

Thanks for the help guys!
 

adrianmach

macrumors newbie
Jul 3, 2017
1
0
FIXED! I looked around the settings some more, found the problem and verified it when I found others with a similar issue. (I was searching "dimming" when I should have been searching "brightness" LOL) Apparently it automatically adjusts to light. So when I was in the library all day it was the same light and everything was fine. In my room it was adjusting to the pockets of light and shadow as I was moving around.

:apple: > System Preferences > Displays > Automatically adjust brightness

Thanks for the help guys!
[doublepost=1499130935][/doublepost]this worked for me. Stopped the auto adjusting.

Thanks
 

WillNN

macrumors member
Feb 26, 2016
45
31
Thanks everyone for this. My MacBook just started doing this. I went to Apple Discussions, turned off Automatically Dim Screen option, and reset the SMC: No change. Apple apparently doesn't want me to post the question. I just get the spinning 'get lost' thingie. Then I found this. USB-C power plug. Thanks following it down.... I found out it was plugged into an Anker adapter-- I've got two USB-Cs in the dongleghetti (reminds me of the lady in the old peoples' home who used plug a lamp into an extension cord, then run the extension around a chair and plug it back into itself...) The Anker brick is rated high enough for the 15"2017 MBP, but it's not the big white one.
 
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