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

[Kaveh S]

The problem still occurs for me. I have firmware 2101.1 Samsung Q800T 75" 2020.

[SidL]

Is the contrast issue in white images still in the new update then? I don't think this will be fixed anyway! The best thing is to migrate to an OLED from LG!

[peterQ95T]

@Pathfinder..no need oled choose Sony they know how to make good Tvs. My cheaper sony A89J is better then my Q95T…i will never go back to Samsung.

[Peto Pedro]

I don't have any issues 

Running PC RiG and 

Contrast is fine.

I don't even use HDR

It will be even darker

Set brightness to 30

Contrast to 30 

Sharpness 10 

LD on low 

Color tone cool 

Gamma BT. 1886

Shadow dwtail zero 

And picture is perfect 

[Doog]

I have a Q82T with the latest 2101 firmware and have found this thread because of the strange dimming issues I'm experiencing, although they have nothing to do with gaming mode.

Basically I have turned all energy saving features, adaptive brightness etc off, and set the TV as bright as I can. When the TV turns on it is perfect and really bright with a stunning picture, but after around 10 seconds the image suddenly dims around 30%-40% completely ruining the picture and making it almost unwatchable. I have tried changing every setting I can find and think of, but nothing makes a difference. It does this every single time I turn on the TV, and nothing I do or change makes it go brighter again like it was when the TV first turned on.

Bizarrely, it is most obvious when I access Ambient Mode, as the screen goes so dark I am almost not able to read what is being said on the screen.

I take it by the fact that this thread is 199 pages long that no fix has been found? I'm wondering now if my 11 month old TV cannot be fixed will I be able to get a refund?

[Peto Pedro]

U need to go to eco settings and turn dat sht off

[Doog]

Thanks but that was the first thing I mentioned in my post, all eco modes, energy saving, adaptive brightness etc is turned off. The TV first turns on completely bright and then after a few seconds it dims really noticeably by itself, and no amount of adjustment makes it bright again

[Peto Pedro]

Erase tv to factory reset if not solved then warranty or try cover ambient sensor

[Doog]

Thanks again for your response. I tried 2 factory resets but that didn't work. Where is the ambient sensor? Obviously that is not something I should have to do, but I guess if it works..

The TV is under warranty, but I thought this was a fault with all of these TVs? If not then I guess there is hope

[Peto Pedro]

Check bottom of the panel for sensor