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

[LCDeez]

Yeah, it happens in other games but FIFA is the benchmark. It’s the one that shows the issue most clearly. Also, I have to ask, why are you even here if you don’t have the issue? This is a support thread for those of us looking to get the issue fixed. You don’t have skin in the game so to speak.

[cod]

Well, Call of Duty is ridiculously bright in most maps. I'll have to test out some other games while keeping an eye out for the issue. Although, maybe it's cos I've got the 85" Q95T, and that has the One Connect box? Or maybe the 85" has a different panel? I'm trying to think of a reason why it wouldn't have happened on my set (not that I'm complaining - if I'd paid north of 5K for a set that did as described I'd be fuming)

[cod]

"Also, I have to ask, why are you even here if you don’t have the issue?"

Because, perhaps the fact that it's not happening with every set carries some useful information

[LCDeez]

Maybe, could be a combination of zone count and utilizing a slightly different algorithm for those zones. The problem I see with this panel variation theory is that people who own a Q80 get the dimming and people with a Q900 also have it. Those panels are totally different leading most of us to understand it’s a software issue. Why it’s not happening on the 85”? We might never know because why trouble shoot something with no issues. 

[LoreCannon]

Q90T owner here, in the us on 1301.5. Also having this issue. Samsung support wasn’t much help. They just want to send a tech out. 

[LCDeez]

Elevate to tier 2 and see if they can remotely fix through service menu.

[LoreCannon]

Not sure if it’s different here in the US but they told me there was no T2 and the closest thing they had was sending out a tech. Though with covid as bad as it is here, I am hesitant to allow that. 

[Suriya]

FIFA looks fully brighter areas not random like last of us2 (ex: entering some dark room and forest areas) so display brightness is adjusting according to the scenes so You missed the dimming bug because of it. Just keep some static image like last of us 2 main screen before entering the game set timer for 7min keep watching the tv you'll definitely see the bug what we're talking about.

[KindOldRaven]

I can confirm that my Q90T has a similar issue. It just seems a bit less extreme here from what i've seen for some reason, perhaps due to the different zone count/agressiveness of the local dimming between the 80t and 90t, but it's definitely still there. It's just easy to miss in dynamic content due to the dynamic brightness, just like you said. 

[cod]

I had it sitting on the lobby screen on Call of Duty for about 20 minutes, brightness never changed.

Going to try with some other games later on, see if it happens with them.