Samsung Galaxy Tab 8 +

[userkfvD43NpPf]

I have Samsung Galaxy S8 + Tablet. I want to know if anyone is having this problem or if it's just me. I don't know if this has anything to do with the latest software update to 5.1.1. I am able to increase the brightness but once it reaches up to the the red bar, the beginning until the end of it, there is absolutely no increase in the brightness. It wasn't like this when I first bought it and I had it for over a year. This problem might have started when I did an update to the software. I am not sure. I want to know if anyone else is experiencing this? I send the tablet for repair and they said they found nothing wrong. Is anyone else experiencing this same exact problem? My Samsung Galaxy S6 tablet has an older version and there is no problem with this. I put it side by side and see the extra brightness on the S6 tablet compared to the S8+ tablet.

[bill-e]

What I noticed on my Tab S8U is that the screen does increase in brightness but one really has to look as it doesn't seem to be a linear increase... meaning more adjustment below the red and less of an increase above it. 

[userkfvD43NpPf]

I did a factory reset a few times and for the first 10-15 minutes the brightness is good and it let's me increase to the maximum. Then while using it, it randomly dims off by itself. Adaptive brightness and eye comfort are turned off. I called Samsung technical support and they checked all the settings and it still does the same thing. Once it dims, I have noticed that once it reaches the beginning of the red bar below that there is a message saying something like to prevent overheating the device the brightness cannot be increased any further so when I increase the beginning of the red bar and up it doesn't increase the brightness at all. Then while I am using it the extra brightness increases by itself randomly and then dims off again by itself every now and then. What can be causing this? Can this be the battery, screen, proximity sensor (whatever that is), the newest operating system, or something else?  Here is a video I uploaded showing what the problem is. On the video the maximum brightness was dimmed, then later one while using it, the screen went back to maximum brightness on its own, then later it dimmed again by itself.

https://www.youtube.com/watch?v=PuE1pL99OxA

[bill-e]

That is very similar to how mine operates.  I have to move the slider slowly and look closely to see any brightness  change in the red part but I believe that it is there, albeit barely noticeable on my tablet. 

You mention that it works for a short time after Factory Reset.  That says to me that something, an app, is affecting it. You also mentioned, then deleted in one of your edits, that you were getting a warning message, again something that suggests something is affecting it. 

First try it again after you boot to Safe Mode. if it is an app it should work. 

Next thing to try is a Factory Reset without restoring any backup so we can see how it operates in a Factory new condition. 

If the issue is still there I guess we can't rule out an update causing it and all you can do in that case is wait and submit an error report. 

[userkfvD43NpPf]

No the extra brightness isn't there. I can easily see if it is or not. I also did a comparison with the S6 and it looks dim on the S8+ compared to it. When both of them are at maximum brightness they look the same for the brightness. It doesn't matter if I increase it slow or fast. The problem is that the brightness keeps dimming and it turns on by itself and then off. The only app I installed are the ones that come with the tablet. 

[bill-e]

Still, try it in Safe Mode. 

1. Pull down the top menu and press the Power icon so that the Power Off and Restart icons appear

2. Press and Hold the Power Off icon until the green Safe Mode icon appears

3. Tap the Safe Mode icon and the phone will reboot into Safe Mode

4.  To exit Safe Mode,  just reboot. (you may have to take it off airplane mode when it restarts) 

[userkfvD43NpPf]

The warning message was the message I posted about overheating. I don't know why I have to use the tablet in safe mode if that's not how I will use it. I never backup any information when I do factory reset so that can't be it. 

[bill-e]

The Safe Mode is used to troubleshoot problems.  It puts the tablet into the as delivered configuration.  If it works in the Safe Mode and not in the normal boot mode it tells you that something, an app, is installed that is causing the issue. 

From there you go back to normal boot mode and try to determine, usually by process of elimination, what the problem app is. 

Sometimes it's easier to just Factory Reset the device and not restore the app backups, and install the apps that you are currently using manually watching to see if the behavior returns. 

Your comment "I never backup any information when I do factory reset so that can't be it." I assume means that you don't restore the backup and if that is indeed the case and it works better in Safe Mode, then one of the apps that you are installing after the reset is the issue, which sometimes happens after a system update when a developer is slow to update his app. 

[userkfvD43NpPf]

They did a fenrir update because technical support suggested it so that's what they put on the ticket. That's the only thing the repair center did. Should this fix the problem? If it doesn't then what can it be if I don't install any apps and only the ones that come with it that cannot be deleted? Thanks.

[userkfvD43NpPf]

I got the tablet back from repair and it's doing the same thing. I went to safe mode and the brightness is dimming on and off by itself again. What does this mean? Also I got the tablet back with several cosmetic scratches on it that weren't there before. The repair center is useless. I just did factory reset and it automatically has the same problem with the brightness. This time It's worse because it stops increasing the brightness around the middle of the bar, before it was when I got to the beginning to the end of the bar.