Solved LG TV conn'd to AMD Mini PC is blinking/crackling

Like I said some posts ago, if you are using a TV as a monitor, the TV must be already connected with the HDMI cable and switched to the respective HDMI input. Then you switch on the computer and you minimize the chances of bad sync. Of course your cables must be at least HDMI version 1.4 to get 1080p or higher. If you have a choice in the graphics settings, try both full range RGB and limited range YCbCr output, but in most cases RGB should give better colors.

A Guy said:

Are you changing to the TV after the PC is already on? If the TV is on when you boot the PC, it can be hard for the TV to lock on to the resolution

Also the wrong cable can cause issues. Make sure it's a quality HDMI 2.1 cable. Monoprice usually has good prices. I also saw (retired a few years now) using the ARC/eARC port can sometimes cause issues. Settings in the video card in the PC can also affect things (VRR, G-SYNC)

A Guy

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To answer you 1st question, yes -- almost always. I typically boot the Mini first to give it time to be ready and then I turn on the TV. Interesting. I will also consider going down that cable path as mentioned.

A little further bug that surfaced this morning was that I changed the resolution to above the recommended, which was also above what the TV could handle. I did so to see if the resolution setting was 'stuck'. It wasn't, but when I tried to switch it back to 'recommended' it wouldn't do it properly. It created black bars instead of nudging the image out to the full screen. Sigh.

When all this crepe-ola started I didn't do a reset to factory but instead the 'replace Windows with a new copy' while keeping all my files. I'm starting to fear this was a mistake and that I should have done a complete reset

By the way, this is being typed by an all new Beelink Mini 12th Gen Intel(R) Core(TM) i5-12450H. It seems like a drastic way to troubleshoot but I was in the market to upgrade my desktop PC anyway. (If that wasn't clear, I can use this Mini to test my TV but then move it to my office PC desk.) Still updating this Mini to current versions of things.

So the new Mini PC. It's... interesting.

There's no flickering. However -- the LG set still does this odd thing. You can be using it for like 25 minutes, everything is good -- and then all of a sudden -- the screen goes black. When it comes back, everything is much BRIGHTER. As if there's a conflict and either the PC refuses to accept the LG screen brightness settings... or the TV rejects the PC's brightness settings.

The new Mini had trouble updating to the recent update, 23H2. It was stuck at 21H2, which is crazy town. So I used the Microsoft Software updater that forces the update to current. There's only one bug I catch and it was there before I updated, namely the drag and drop items into the taskbar was broken.

This has been brutal. Making Macs tempting again, and you have to know how much that hasn't been a thing for me since 2015. But I'm not giving up. Not yet. Have an HDMI 2.1 cable on the way.

The TV must be on before you switch on the PC for better image sync. It is normal for the image to have black bars if the aspect ratio is not set correctly. For example if the TV aspect ratio is 16:10 (1920x1200) and you set it to 16:9, there will be black bars top and bottom. Cycle through the available aspect ratio settings until the image is stretched to fill the screen without cropping or black bars.

If you have trouble upgrading from 21H2 to 23H2 download the new Windows 11 ISO and run Setup.

You people have been so awesome. This morning I got my HDMI 2.1 cable and will give that a try.

Correct me if I'm wrong here, but now that AMD and an INTEL Minis have taken issue with the LG TV, that the TV is likely the culprit? Especially if the new cable doesn't change things?

This would tell me to possibly reset the TV to factory, right?

So the HDMI 2.1 cable is here. Plugged in. Made no difference (still flickering, black outs) and it created a new minor issue --> the boot screen and the desktop are ever so slightly TOO zoomed in. See how the file named 'Untitled' is slightly off the screen?



So at this point I believe it's the TV. I'm about to reset that to factory unless someone screams NOOOOO! lol

The last thing you can try is a custom resolution. Instead of using the default 1920x1080 60Hz with GTF standard timing, you could try creating a custom resolution with CVT-RB timing which is more TV friendly. My laptop's Intel HD 4000 graphics card can do 1920x1080 at 60Hz, but the 4K resolution is not officially supported. I managed to add a custom resolution of 3840x2160 at 24Hz using CVT-RB timing but it is fairly useless as the video stutters in full screen mode.

PS: To make the picture fill the screen without cropping toggle between the available aspect ratio settings. Are you sure the refresh rate is 60Hz? Try 50Hz or 75Hz, if supported, and see if the flicker is gone.

spapakons said:

The last thing you can try is a custom resolution. Instead of using the default 1920x1080 60Hz with GTF standard timing, you could try creating a custom resolution with CVT-RB timing which is more TV friendly. My laptop's Intel HD 4000 graphics card can do 1920x1080 at 60Hz, but the 4K resolution is not officially supported. I managed to add a custom resolution of 3840x2160 at 24Hz using CVT-RB timing but it is fairly useless as the video stutters in full screen mode.

PS: To make the picture fill the screen without cropping toggle between the available aspect ratio settings. Are you sure the refresh rate is 60Hz? Try 50Hz or 75Hz, if supported, and see if the flicker is gone.

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Your help has been awesome. I saw some of this advice elsewhere on the net and will get back to you if needed.

A TV refresh has occurred and that (at the moment) fixed the "cut off slightly" resolution issue. I'm now holding my breath to see if it also fixes flickering and blackouts.

UPDATES --

Theory #1. Not long ago I turned off the auto dimming and auto-care modes on the TV. It may have not liked that much.
Theory #2. I wonder if a person compounds brightness and night light settings between a TV and a PC that the TV becomes confused.

Kind of like you attach a USB cable from your phone to an older car stereo system with an Aux in. What happens is you have two volume knobs: the car knob and the phone buttons. You know how sometimes you can't figure out why you don't have volume and you learn, oh, the car volume itself is kinda low to begin with.

When connecting an audio playback device via analogue cable, such as a cassette player in the computer's line in audio port for recording, I usually set the device volume to max (unless there is distortion) and control the audio level from the computer by adjusting the line in volume. Unless there is distortion, this gives the maximum dynamic range, so the audio level is neither too low, nor clipping. Obviously if I hear any distortion I turn down the volume from the device until there isn't any and then control the level from the computer. If the end result is slightly lower (but not too low as to compress the dynamic range too much), I can then use Adobe Audition or similar application to normalize the sound (maximize the dynamic range without distortion).

So the jury is in. The verdict: the LG TV had to be reset to factory. It never had anything to do with the Mini PC (take that Apple!) or the HDMI cable. All blackouts and flickers are gone.

The question is what went wrong? I don't really know.

1. There's a possibility that the TV software went buggy. Unfortunately there's no way to determine if that's true.

2. There's a possibility that playing with the TV settings may have confused the set. For instance, and a long time, I ran the set in a mode where it handled the OLED brightness automatically. Recently (perhaps the cause of issues) I manually took over the OLED Pixel brightness and lowered them to 40%. This, in conjunction with Filmmaker mode (already a dimming tech) in conjunction with the PCs Night Light settings may have confused the set. And so from this point forward I'm going to be very cautious about playing with LG's settings. If I accidentally re-create the issue again at least this time I'll know what's what and come back here and report it.

I want to thank everyone who tried to help me during this miserable two week plus process. I used to find such things a kind of fun challenge but this was horrible. (Cause I was/we were trying to fix something that wasn't broke, lol.)

The Pool Man said:

There's a possibility that the TV software went buggy. Unfortunately there's no way to determine if that's true.

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That is a very good guess. I know mine has had more than a few updates since I got it 2 years ago, but I only use it for Live TV and Google TV / YT TV via my ChromeCast with Google TV. And I've not had a single issue with the CC, in terms of picture quality degradation.

The Pool Man said:

There's a possibility that playing with the TV settings may have confused the set. For instance, and a long time, I ran the set in a mode where it handled the OLED brightness automatically. Recently (perhaps the cause of issues) I manually took over the OLED Pixel brightness and lowered them to 40%. This, in conjunction with Filmmaker mode (already a dimming tech) in conjunction with the PCs Night Light settings may have confused the set. And so from this point forward I'm going to be very cautious about playing with LG's settings. If I accidentally re-create the issue again at least this time I'll know what's what and come back here and report it.

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I didn't even consider PC Night Light as a possible cause, because the few times I've used Cast to cast my phone, even if Night Light is on on the phone, the image on the TV is without Night Light. But, I'm displaying via Wi-Fi by casting to aforementioned ChromeCast, so that probably works a lot different than using the TV as a second monitor via HDMI.

Good sleuthing on your part, and great job @spapakons stepping in when I was not here due to illness in recent days in keeping the troubleshooting alive.

johnlgalt said:

I know mine has had more than a few updates since I got it 2 years ago, but I only use it for Live TV and Google TV / YT TV via my ChromeCast with Google TV. And I've not had a single issue with the CC, in terms of picture quality degradation.

Good sleuthing on your part, and great job @spapakons stepping in when I was not here due to illness in recent days in keeping the troubleshooting alive.

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I was wondering what happened to you. I fear I made you sick with all my issues.

Lol - if only!

No, I was bed ridden for 4-5 days, it was pretty bad/

Make notes (or take pictures) of your settings so you can return to them if changing them causes any issues (or you do a reset again).


A Guy

An advice for using a TV as a monitor. Avoid configuring your TV to handle brightness and motion artifacts. Most likely will make the picture unnaturally smooth, almost blur, and with weird colors that are hard to fix. I would completely disable any processing from the TV or at least put it to the lower setting. I would select the normal color profile, no games or sports or whatever. Once the image on the TV is as neutral as it gets, open Control Panel in Windows and go at color preferences (or similar). At the last tab there is a button to calibrate the display. First make sure you have reset your TV image settings to default, and then click on the button to do the calibration. You will be surprised how better the image will look. After that you will be prompted to do cleartype calibration as well. Do it for clean easy to read text.

I also noticed that when playing old games in standard resolutions, such as 640x480, 800x600, 1024x768, they are not always look good due to the TVs not-ideal scaling. To improve this you can go at graphics control panel and change scaling from display to GPU. You can set the resolution to 1920x1080, for example, and scale all lower resolutions with GPU to fill the screen. Some games, such as arcade emulator MAME, even let you specify the display resolution and scale the game at that without depending on the monitor to do a lousy job.

A Guy said:

Make notes (or take pictures) of your settings so you can return to them if changing them causes any issues (or you do a reset again).

LG C1 OLED Calibration Settings

We used the following calibration settings to review the LG 55 inch C1 (OLED55C1), and we expect them to be valid for the 48 inch model (OLED48C1), 65 inch model (OLED65C1), the 77 inch model (OLED77C1), and the 83 inch model (OLED83C1).

www.rtings.com

A Guy

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The recommendations are interesting but a bit involved. I'm scared to try too much. What I did do was regain control of pixel brightness (it's just too dang bright!) and set the TV a lot less bright for the time being.

An interesting thing occurred to me to try while doing. Ladies and Gentleman: day mode and night mode.

I've noticed that no matter how I set things up that at night time the set feels brighter. That's because there's no more daylight and most of the lights in the room are off for cinema effect. This results in me needing to adjust the set all the time for day and night.

But today I'm trying setting up two custom picture modes. I've adjusted CINEMA for day and FILMMAKER for night. So when night rolls along I just flip one switch and my custom mode is waiting.

Thanks for the help friends. I'll keep ya posted.

As far as I know the night mode makes the overall picture yellow to avoid eye strain. It doesn't reduce the brightness. I prefer normal colors. If I need to dim the picture I can reduce gamma value from graphics control panel. However when viewing from normal distance the screen is OK, even with the lights off. It is not extremely bright as to need to dim it.

It reduces blue light. Hence the yellowish / amber coloration.

And some people have greater sensitivity to brightness in darkened areas.

In some devices night mode is a little yellowish and you could adapt, but in others it is ridiculously more, like the whole image is in shades of yellow. I prefer cool colors over warm anyway, so I never use night mode. Even if only slightly yellow, I don't like the look of it, I prefer natural colors when watching movies.