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Original topic:

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

(Topic created on: 24/02/21 14:52)
Rauttis
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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

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PeterHu
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No workarounds as far I know, only hope for update. Someone commented below a video (Produces by KG, he owns a Q90T) 2020 QLED will have an update in March.

Otherwise meanwhile I returned my 65Q90T (they admitted the vertical banding) and asked full refund. I'm waiting for the new NEO QLED QN85A and QN90A availability. Reviews started to appear and the QN90A seems impressive and worth to wait. If not, I might go for an LG CX or new C1.

QN90A unbiased great review:
https://hdguru.com/review-samsung-65qn90a-neo-qled-pushes-lcd-needle/

With good comments:
https://www.avsforum.com/threads/samsung-neo-qled-qn90a-4k-tv-hands-on.3183800/

Galaxy_Echo
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The Samsung TV usually has nice spec on paper but terrible user experience and lots of annoying issues. I suggest you don't give their MINI LED TV too much expectation before using by yourself.

Take 2020's Q90T for example :

  • It has HDMI 2.1. Sounds good? Their HDMI 2.1 can't afford 4K + 120fps + HDR while pairing with PS5.
  • It has eARC. Sounds good? Its eARC can't passthrough DTS and multichannel LPCM.
  • It has 120 dimming zones. Sounds good? Its terrible local dimming algorithm makes brightness of subtitle fluctuated and looks worse than X900H which only has 32 zones.
  • It's "QUANTUM" LED. Sounds good? Its color gamut can't even catch up the standard level of other LED TV.
  • It has the lowest input lag in TVs. Sounds good? It sacrifices almost all local dimming capability so that its Game mode looks like a low end TV with only global dimming.
  • It has high peak brightness. Sounds good? It has also the brightness auto-dim issue that dims your brightness in period time for unknown reason.
  • It supports VRR. Sounds good? You won't like to use its terrible VRR function again since it makes color and contrast washed out.
  • Its PWM frequency is 960Hz. Sounds good? It only happens in limited situation "Movie mode with MEMC turned off" and "Game mode with VRR turned on", in most modes you still have to endure terrible 120Hz PWM.
  • Their firmware changlog never honestly tell you what they fixed or messed up, they just give you an encrypted description and test you if you can find the answer.

I was ever charmed by its great spec. After spending money to buy such a TV which only offer me angry and disappointment instead of entertainment, now I become a Samsung TV hater.

PeterHu
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I hear you and I understand. I've been there, I had Q90T and the problems you pointed out are valid. That's why I believe Samsung has to proove this year as their sales in 2020 probably dropped and not only because of the pandemic. It's well known 2020 TVs were more like a facelift after the R-series and even downgrades on many fields. They knew Mini Led is on the way so the T-series was designed to fill the gap. (I am sure next year will be a minor upgrade as well with more dimming zone and more HDMI 2.1) Because of the new backlight now they had to rewrite the firmware and optimalize for the new technology, that's why I give them one more chance. And I'm afraid they won't fix the 2020 series fully as they will focus on the next generation. One HDMI 2.1 is enough for me (for a future PS5 maybe).

Otherwise if they fail, I go for a CX/C1 and that's all (I have a very bright living room with nice view so I wanted to avoid to place curtains but I will if I have to) Let's see.

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Usernewx213
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Hello everybody

Just wanted to share a quick follow up.

Subscribers might remember the video I posted. For my dimming problems I found some work-arounds for subtitles using kodi. Far from satisfactory, but with all the horror stories here, I didn‘t want to risk a warranty substitute with even more problems. The problems got worse though, so I started a warranty case.

BUT

You will not believe this!!

Literally the first time I powered up the TV after I let the email out, ALL my problems were gone! Perfectly working TV, no crazy dimming, no f**** up endtitles, blooming test video from youtube that was horrendous before looking brilliant.... 

Been 3 weeks since, all good. Can‘t explain it... unfortunately I can’t say it is a secret mix of commands, but there you go... I‘m happy.

 

 

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peterQ95T
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Samsung have release 24 of Feb  new firmware for Q90T in the US.

Ver 1462.1    

I hope samsung will release it soon i n Europe.

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GD_UK_2020
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Not available in the UK yet for my TV. The change log is generic:

- Model : Q950T, Q900T, Q850T, Q800T, Q90T, Q80T, Q8DT, Q70T, Q7DT, LS03T, LS01T
- Version : 1462.1
- Improved usability 1. Improved picture quality 2. Improved browser performance 3. Improved app performance 4. Improved stability 5. Improved usability of input devices

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Mdsmarques
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I'm experiencing this bug on Q80T on Prime Video with HDR10+, anyone else?

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RouDeR
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  • 1497.0 is now available in Europe
slx
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anyone tested that yet ?

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RouDeR
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As expected, HDMI 2.1 compatibility issues are still NOT fixed, my RTX 3070 gives black screen when turning on Game Mode and have to replug the cable several times / restart the PC / restart the TV, till the freaking Game Mode starts to work.

What a Joke of a company has Samsung become..