Resolved 2020 M1 MBA screen brightness fluctuating

[ixxx69]

My 11 month old 2020 M1 MBA screen brightness is fluctuating even though I have the preference "automatically adjust brightness" turned off. It happens very randomly and intermittently.

Sometimes a week will go by and it's fine, and then it will happen a number of times over the course of 15 minutes where the screen brightness goes up and down a step. Then it's fine for a few days, and then it pops up again.

Does this sound like a failing screen that I have to get to an Apple store ASAP, or has this behavior been noticed before and maybe it's a macOS issue?

If it's a failing display, I don't know how I get Apple to acknowledge that without seeing the screen issue themselves, which is unlikely in the course of normal diagnostics, as days can go by without it showing itself.

 

[JPack]

Maybe it's something you can record? But I'd run the issue by the Apple Store first. Maybe it's an ambient sensor diagnostics will identify the failure.

 

[ghanwani]

Do you also have true tone disabled?

 

[Macak]

Maybe you will find and answet here:

MacBook Automatically Lowering Brightness on Battery? Here’s How to Fix it

Is your MacBook Pro or MacBook Air automatically lowering the brightness of its display whenever it’s on battery? This may be happening for several different reasons, but it’s nothing y…

osxdaily.com

 

[ixxx69]

Do you also have true tone disabled?

I do! However, the lighting conditions were consistent during the fluctuations. Is true tone known to do this even in consistent lighting?

 

[ixxx69]

Maybe you will find and answet here:

MacBook Automatically Lowering Brightness on Battery? Here’s How to Fix it

Is your MacBook Pro or MacBook Air automatically lowering the brightness of its display whenever it’s on battery? This may be happening for several different reasons, but it’s nothing y…

osxdaily.com

Thanks, but that doesn't mention anything about fluctuations that I saw.

What's happening is the screen lowers a step in brightness, and then 5 seconds later, it raises a step in brightness, and then 10 seconds later it lowers, and then 5 seconds later it raises, and then it's fine for 10 minutes, and then similar happens again, and then it goes away for a week before reappearing. I haven't noticed it since my OP, but this has been happening for at least a couple months.

I believe it's happened both when I'm plugged in and unplugged, but I'll have to pay more attention as I'm not sure.

BTW I'm on Big Sur 11.6.

 

[ghanwani]

I do! However, the lighting conditions were consistent during the fluctuations. Is true tone known to do this even in consistent lighting?

I don't think it's supposed to, but there could be a sensor not performing to spec.

 

[ixxx69]

just an update that I turned off True Tone and it still happened today just briefly a couple times during a few hours apart.

Next is to see if it happens while on battery. It's definitely happened while on the charger.

 

[ixxx69]

Just an update for anyone who comes across this thread with a similar issue.

Issue seemed to get progressively worse, but also noticed it never happened while on battery.

Turns out it was my third-party charger. I feel dumb that didn't occur to me to check into that earlier. I just never suspected it, as it's a 65W charger and had no issues keeping the MBA fully charged. However, there must be something going on with it. I have the macOS preference settings set to dim the display while on battery power, and the intermittent flickering seemed to be caused by the MBA rapidly changing between states of charging and on battery.

Switching over to the Apple supplied charger fixed the issue. I suppose I could also set the preferences to not dim the display while on battery power, but I'd be a little concerned that the constant switching of charging states might put strain on some component, so probably better for me to just stick with the Apple charger.

 

[StoneJack]

Ok probably it was a cheap shtty charger for 10 bucks on sale and maybe not even for a notebook