2020 QLED T models (Q80T, Q90T, Q800T, Q900T) HDR game mode brightness / local dimming bug

[Rauttis]

I bought a Q80T a couple of days ago and have noticed a really annoying issue when using the tv with the combination of HDR and game mode.

I'm fairly certain this is a software bug in the TV since I can reproduce this issue with 100% accuracy, and it happens on the dot at the same moment every time. It's basically on a timer.

Basically when the game is displaying a HDR signal and game mode is enabled, exactly after 6 minutes the brightness of the TV suddenly drops by around 20 (50 -> 30). The value of brightness setting doesn't actually change however. Messing with the brightness setting does not restore the brightness to it's original state, but changing the local dimming setting from standard to low and then back to standard does. Switching game mode off and then back on also fixes the issue, but then it happens again EXACTLY after 6 minutes (I've timed this with a stopwatch).

Has anyone else experienced this issue? Or can someone maybe test this on their TV to see if you can reproduce it?

Exact repro steps on how I can reproduce this 100% of the time on the PS4 Pro:

1. Set brightness to max (50)
2. Set local dimming to standard (bug happens on high as well)
3. Enable game mode
4. Turn off game motion plus
5. Turn off intelligent mode and all the brightness related settings in eco settings, as these can influence the brightness level of the tv.
6. Launch a game that runs in HDR
7. Start your stopwatch
8. Do whatever you want in the game or you can also go back to PS4 menus, find a bright scene where you can notice a brightness drop easily
9. When the stopwatch hits 6 minutes, you should see the TVs brightness suddenly drop by a large amount. By eye the brightness drop seems about equal to dropping the brightness from 50 -> 30 by hand.
10. Go to picture settings and set local dimming to low (brightness does not change)
11. Set local dimming back to standard (brightness suddenly jumps to the original level. Brightness can be restored by switching input away and back as well, or by disabling and re-enabling game mode)
12. And again after EXACTLY 6 minutes the bug again repeats and the brightness drops down again

Some other notes: The PS4 has a screensaver that basically dims the screen if it is idle for a while. This is not the cause of this, this happens even when the console is in active use and the brightness can be restored temporarily by changing the local dimming setting like described above. I have not managed to reproduce this issue with game mode off, so it seems to be related to game mode.

Software version: 1304

[CarlH]

Hi @Rauttis. Can you confirm the software version you're currently running on your TV? This can be found by pressing Settings on the remote and going to Support > About this TV. 

[Rauttis]

The version is 1112. According to the TV there are no newer versions available.

The more specific version under about this tv is: T-NKMDEUC-1112.9, B0040700/B30200, BT - S

I've also managed to reproduce this issue on a Nvidia Shield now just to confirm this is not a PS4 specific issue. The steps are basically the same. Enable game mode and watch something with HDR. After exactly 6 minutes the brightness of the TV drops by a large amount and does not return back to the original level by itself.

[moejeremiah]

Having the exact same issue with the xbox one x.

[RouDeR]

I have similar issue with the brightness on my 75 inch Q800T even without GameMode or HDR.

It is 100% related to the Local dimming algorithm.

When my picture gets dimm > I need to change my LD settings to Low, then back to High or Standard to get the brightness again.

Workaround for this issue is to access the Service Menu and there is an option to disable Local Dimming support for PC MODE.  I did that and I no longer have brightness fluctuation! However the cost of not having Local Dimming is too high, SAMSUNG MUST FIX THIS WITH SOFTWARE UPDATE!

Software version 1115.5

[funkybananas]

Noticed this on my Q95T too in game mode. No fluctuations out of that mode thankfully! 

Any word on a fix for this?

[Luke_H]

I'm also experiencing the same issue. Currently running between Sky Q and a Xbox one X. 
It's noticeable across all content. Sky, Xbox, Netflix via Xbox app. As I type this it's happened once, and twice since researching this a little. 

currently running the latest firmware. Surely there's some support here for this issue?? Clearly somethings going on and this fix on entering the service menu seems a huge inconvience!!! 

Help please Samsung!!!!

[jayh89]

Did you ever fix this? I am having a similar issue.

[Luke_H]

Unfortunatley not. Having the same issue consistantly. Happens daily and is incredibly frustrating given the cost of the TV.

Any help from someone in support???????

[SexChromo]

OK so not 100% sure  This will solve the issue you guys are having with HDR and game mode but I am having the same issue with watching Blu-Ray disks on my xbox. The screen would automatically dim after about a minute of resetting the brightness to a higher level.   The fix that I found is to adjust the Eco solution setting which to save energy automatically dims the screen when ambient light in the Room is detected below a certain level. 

Go to: menu/settings/general/Eco solution and you should be able to adjust those settings accordingly.

This has worked for me but  I haven't tested while actually playing a game.