Question Can't stop LG C8 from auto dimming

kurtdh

Member
I watch a lot of Twitch on my LG C8 using an Nvidia Shield Pro 2019. I noticed after watching a stream for a couple of minutes, that the brightness of the panel decreases dramatically. When I first noticed this, I did some research, and found out how to turn ASBL off in the service menu, from this link:


However, even after turning ASBL off with the above instructions, the screen STILL dims a couple of minutes after watching a streamer on Twitch. I watch twitch using the s0und TV app from the Android TV app store. Thinking it could be an app issue, I also tested with the official Twitch app, and it does the same exact thing. I don't seem to have this issue when watching regular TV or movies on the shield, only when I watch Twitch. To me, this seems that maybe the TV is detecting a static image on the screen (such as the streamers face cam on the screen), and dimming the panel. I also tried changing the HDMI 1 input (the one the shield is connected to), to a PC input, and that didn't fix the issue either.

I posted this on reddit as well with no luck. This issue is driving me NUTS, and I can't imagine I'm the only person this is happening to. Can anybody please help me, or advise what the issue could be, and how to potentially fix it? Any help would be GREATLY appreciated. Thank you!
 

Sledgestone

Active Member
It sounds like the same problem I have on my C9. I believe that the problem has to do with the logo luminance setting. Turning it off helps a little, but the dimming is still present.

Not sure yet if it’s my TV that is malfunctioning or that every set has the same issue.
 

kurtdh

Member
It sounds like the same problem I have on my C9. I believe that the problem has to do with the logo luminance setting. Turning it off helps a little, but the dimming is still present.

Not sure yet if it’s my TV that is malfunctioning or that every set has the same issue.

Can confirm turning off logo luminance setting does not fix the issue. I’m having a hard time believing nobody has ever been able to answer this question for me.
 

j82k

Member
It's been discussed a few times here and also on avsforum. You can't disable this new dimming algorithm. It will trigger when part of the picture is static for two minutes. I measured it here:

 

Sledgestone

Active Member
It's been discussed a few times here and also on avsforum. You can't disable this new dimming algorithm. It will trigger when part of the picture is static for two minutes. I measured it here:


Can you confirm that this is present on the C9 also? And that it will trigger during football games with scoreboard and logo?
 

j82k

Member
I don't watch football and I don't have a C9 but on the german hifi-forum there is a 7 page thread about this, many complaints about dimming when watching football including C9 owners....
 

Sledgestone

Active Member
I’ll check it out. Your test result is pretty similar to mine. Mine dims, and it dims a lot. Don’t really get how this is not discussed more.

However I’m more at ease now that I know that it’s not my panel that’s malfunctioning.
 

kurtdh

Member
It's been discussed a few times here and also on avsforum. You can't disable this new dimming algorithm. It will trigger when part of the picture is static for two minutes. I measured it here:


Thank you so much! It seems as part of that thread, people are trying to find an easy way to replicate this behavior without having to superimpose a box onto the screen. The solution is simple, just watch a Twitch stream of a streamer that has a face cam. I use an nvidia shield to watch Twitch, and it auto dims every time, and is super easy to replicate.

Can you please tell me if there's an OLED TV out there that does not have this problem/feature? This is extremely detrimental to my viewing experience, and if I can convince LG/the retailer to give me a refund, I would be in the market for a TV that does not experience this behavior.
 

lgans316

Distinguished Member
ABL drove me nuts on my C8 whilst watching some films even on low APL dark scenes.
 

kurtdh

Member
It's been discussed a few times here and also on avsforum. You can't disable this new dimming algorithm. It will trigger when part of the picture is static for two minutes. I measured it here:


in your test you state if the static box is 50% white or below, the dimming never occurs. What do you mean by 50% white? Is this how bright the box is, or how white it is compared to black? I’m trying to figure out what this means so I can tweak my display settings in such a way that it never triggers. Do you think this is possible?
 

j82k

Member
I used greyscale calibration pattern to simulate the static logo. 50% being the stimulus level, meaning a darker white or rather grey.

You can't influence this dimming with TV settings from what I can tell, lowering contrast or oled-light had no effect.
 

abb13

Member
I have a C9 and was noticing the same dimming problem and how it doesn't relate to any setting that's on. When I started searching for it I found info about turning off a setting in the service menu, but I wasn't able to figure out any ways of accessing that I looked for online. This thread seems to be suggesting that setting doesn't even fix this, so I'm not sure if I still need to be trying to solve how to access that menu or if I should just get used to how this happens.
 

Sledgestone

Active Member
I have a C9 and was noticing the same dimming problem and how it doesn't relate to any setting that's on. When I started searching for it I found info about turning off a setting in the service menu, but I wasn't able to figure out any ways of accessing that I looked for online. This thread seems to be suggesting that setting doesn't even fix this, so I'm not sure if I still need to be trying to solve how to access that menu or if I should just get used to how this happens.

What are you watching when it starts dimming? If it occurs during sports then you seem to be out of luck. I’ve tried everything without success.

You can try setting logo luminance in the settings to off and see if that helps. Also turn off all eco and AI settings.

If it dims during long dark scenes you can turn off ASBL in the service menu. You can access it with a lg service remote, harmony remote or an android app.
 

Inferno

Distinguished Member
What are you watching when it starts dimming? If it occurs during sports then you seem to be out of luck. I’ve tried everything without success.

You can try setting logo luminance in the settings to off and see if that helps. Also turn off all eco and AI settings.

If it dims during long dark scenes you can turn off ASBL in the service menu. You can access it with a lg service remote, harmony remote or an android app.

It can be stopped in the In Start Menu, or Service Menu, if you want to stop it, it's not for the faint hearted and I am sure this could cause problems but I bought it, and I was fed up with the Dimming.

20200110_120814.jpg


20200110_120841.jpg
 

Inferno

Distinguished Member
What happens when you turn the dimming off? I’ve read that it stops the dimming but force locks the Oled light to 100?
No it doesn't do that, my oled light is at 30 on Techinicolour Expert and on the Calibrated ISF Night it's on 60, not 100, who told you that, their not correct.

EDIT : Well that is what mine is reading?

And iirc it was Professionaly Calibrated with the Dimming OFF.
 

Sledgestone

Active Member
No it doesn't do that, my oled light is at 30 on Techinicolour Expert and on the Calibrated ISF Night it's on 60, not 100, who told you that, their not correct.

EDIT : Well that is what mine is reading?

And iirc it was Professionaly Calibrated with the Dimming OFF.

Ok. There was a few people on the C8 general thread that said that. Will have a go and see what happens.
 

Inferno

Distinguished Member
It may well do on a C8, mine is a B9 and I have just lowered and upped the oled light and it was making the screen darker and lighter so on my set it works, maybe it's different on the C8, IDK.
 

Sledgestone

Active Member
Do you know if the dimming option is actually ABL? Or is it something else?

How long have you had it disabled? No issues with screen burn?
 

kurtdh

Member
It may well do on a C8, mine is a B9 and I have just lowered and upped the oled light and it was making the screen darker and lighter so on my set it works, maybe it's different on the C8, IDK.

On c8 it definitely locks the oled backlight to 100 when you set dimming off. I know because I tried it myself on my c8. Wish I had a b9 now instead so I could solve this issue by turning that off. I can’t watch twitch for longer than 2 minutes without it auto dimming. Sigh.
 

abb13

Member
What are you watching when it starts dimming? If it occurs during sports then you seem to be out of luck. I’ve tried everything without success.

You can try setting logo luminance in the settings to off and see if that helps. Also turn off all eco and AI settings.

If it dims during long dark scenes you can turn off ASBL in the service menu. You can access it with a lg service remote, harmony remote or an android app.
It brightens or dims both times when it's bright or dark for an extended time, but there are times it seems to be dark and gets darker for some time and it's like I have to wait it out to brighten again. So it seems exactly like an auto brightness setting, but I have all of those options off.

I think my android phone doesn't have IR that's why none of those apps will work even though it can do the WiFi connection. There's a product on amazon called "New MKJ39170828 Replace Factory SVC Remocon Service Remote Control Compatible with LG LCD LED TV DU-27FB32C DU27FB32C" Do you know if this the correct lg service remote that would work?
 

Sledgestone

Active Member
It brightens or dims both times when it's bright or dark for an extended time, but there are times it seems to be dark and gets darker for some time and it's like I have to wait it out to brighten again. So it seems exactly like an auto brightness setting, but I have all of those options off.

I think my android phone doesn't have IR that's why none of those apps will work even though it can do the WiFi connection. There's a product on amazon called "New MKJ39170828 Replace Factory SVC Remocon Service Remote Control Compatible with LG LCD LED TV DU-27FB32C DU27FB32C" Do you know if this the correct lg service remote that would work?

You can't do much about the dimming in bright scenes, but the dark scenes getting darker will stop once you disable ASBL.

Is this the one you mean? If so, yes that should work according to the reviews.
 

abb13

Member
You can't do much about the dimming in bright scenes, but the dark scenes getting darker will stop once you disable ASBL.

Is this the one you mean? If so, yes that should work according to the reviews.
Actually, I don't know what order it happens to cause what, but similar to the dark situation it's more like it gets brighter on a bright screen, but changing it for the dark part is enough for me to be worth it.
I was looking at another one but it has that same main number so it should be right. Thanks
 

kurtdh

Member
I used greyscale calibration pattern to simulate the static logo. 50% being the stimulus level, meaning a darker white or rather grey.

You can't influence this dimming with TV settings from what I can tell, lowering contrast or oled-light had no effect.

I am considering asking LG to replace my C8 with a different model. I can’t watch content without my set auto dimming, and nobody warned me of this ahead of time. I know the likelihood of them doing this is slim, but my question to you is this. Are there any other LG OLED’s out there that don’t suffer from this issue?
 

Roohster

Distinguished Member
I am considering asking LG to replace my C8 with a different model. I can’t watch content without my set auto dimming, and nobody warned me of this ahead of time. I know the likelihood of them doing this is slim, but my question to you is this. Are there any other LG OLED’s out there that don’t suffer from this issue?

Even if they agree to do it, a replacement will do exactly the same, they're set up to do that. LG class it as a feature, not an issue.

It was driving me nuts too so I got into the service menu as described above and disabled TPC.
*WARNING* You do this at your own risk.
Follow the instructions carefully if you decide to try it!

I have no idea what the long term effects might be but it's better than putting up with the dimming as far as I'm concerned
 

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