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

[Tv52]

Thanks for sharing your findings! If this turns out to be true then we could be able to rule out the software issue and focus on hardware issue which can be easier to claim on warranty. It would be great if we found someone else with smaller TV and without this issue.

[jayh89]

This is almost certainly a software issue. Not hardware. 

[Luke_H]

I always notice it during game play. 

[cod]

Could potentially be a combination of both though

[jayh89]

We have people in this thread saying they have Q90T with this issue. Also, the panels used in Q80T and Q90T are the same (along with Q800T and Q950TS). I have the Q85T (EU exclusive and same panel with anti-ref coating) and it has the issue. This is almost certainly a software issue. If it was hardware, you'd really expect it to dim on all modes. It *only* happens in game mode for me, no other mode. It doesn't make sense being a hardware issue. Either way, I'm assured by a mod that Samsung are aware of this and are investigating.

[cod]

Well, the reason I was saying potentially a mix of both is that it hasn't happened once so far on my 85" Q95T. If it was just a straight software issue then it would presumably happen on every TV, every model, every size, no exceptions.

[cod]

Hopefully, whatever the case, it's sorted sooner rather than later, since there appear to be a fair number affected, and nobody likes to have their new toys spoiled, particularly expensive new toys.

[jayh89]

Samsung had best hope it’s software! If it’s hardware then they have a LOT of explaining and replacing to do at large expense! 

[LCDeez]

I mean, if tier 2 was able to fix it through service menu, it’s undoubtedly software. 

[Tv52]

Not really. For example if your can have faulty engine that causes oil lekage during rapid acceleration then service could fix it by changing software to prohibid rapid acceleration. This could be small diference but still.

Sometimes hardware bugs are fixed in software way as this is way cheeper.