Why Is My TV Screen Flickering? Causes and Fixes

A flickering TV screen almost always comes down to one of three places: the source (a streaming box, console or antenna), the connection between it and the TV (HDMI cable, port, or a soundbar in the middle), or the TV itself (a picture setting, software, or a failing backlight). The quickest way to find out which is to open the TV's own menu. If the menu is steady while the picture behind it flickers, the TV is probably fine and the problem is upstream. If the menu flickers too, the problem is inside the TV.

Why is my TV screen flickering?

"Flickering" covers a few different symptoms, and the pattern tells you a lot:

• The whole picture pulses or shimmers all the time. Often a backlight setting, an energy-saving feature, or a backlight that is starting to fail.
• The screen blinks black for a second, then comes back. Usually the HDMI connection dropping and reconnecting: a loose or underpowered cable, a port setting, or the source changing its output mode.
• Only part of the screen flickers, or there are flickering lines. Typically hardware, such as a backlight strip or the board that drives the panel.
• It only happens on one input or in one app. The TV is doing its job. Look at that source.

Before you change anything, it is worth separating flicker from two things that look similar. Stutter or judder (motion that jerks along, especially in slow camera pans) is a frame rate issue, covered in our guide to the soap opera effect and motion smoothing. Freezing and loading circles while streaming are buffering, which is a network problem, not a display problem.

First test: is it the TV or the source?

LG's support page for continuous flickering starts with this check:

1. While the flicker is happening, press the Settings or volume button on the TV remote so the TV draws its own menu or volume bar on screen.
2. Watch the menu itself, not the picture behind it.
3. If the menu is stable, the TV's panel and backlight are working. The cause is the cable, the port or the device feeding the TV.
4. If the menu flickers along with everything else, the TV is the place to look.

Samsung TVs have a built-in version of this test. On 2022 and later models, go to All Settings > Support > Device Care > Self Diagnosis > Picture Test. On earlier models it is Settings > Support > Self Diagnosis > Picture Test. The test image is generated inside the TV, so if it flickers, no cable or streaming box is involved.

A second quick check: switch to a built-in app on the TV (or play a video from a USB stick) instead of the HDMI input. Steady picture in the built-in app plus flicker on HDMI points straight at the connection or the box.

Fixes when the source or cable is to blame

Try these in order, cheapest first.

Reseat and swap the HDMI cable

Turn the TV and the device off, unplug the HDMI cable at both ends, and plug it back in firmly. LG and Vizio both list this as a first step. If that does not help, try a different cable. 4K and HDR signals need far more bandwidth than 1080p, and an older cable that worked fine for HD can drop out once the signal gets heavier. Vizio's advice is to use a certified high-speed cable that supports the resolution, refresh rate and HDR format you are sending.

Try another HDMI port

Ports are not always identical. Some TVs only accept full 4K HDR on certain ports, and a damaged port can cause dropouts that a new cable will not fix. Samsung TVs can test the connection for you: on 2022 and later models go to All Settings > Support > Device Care > Self Diagnosis > HDMI Troubleshooting, and on older models Settings > Support > Self Diagnosis > Signal Information > HDMI Cable Test.

Check the enhanced HDMI setting for that port

Many TVs ship with full-bandwidth HDMI switched off per port. Samsung calls it Input Signal Plus and LG calls it HDMI Ultra HD Deep Colour. If a 4K HDR source is plugged into a port where it is off, the result can be a blank or unstable picture. If it is on and your cable is not up to it, you can also get dropouts. Try it both ways, and remember the setting belongs to one port, so check the one you are actually using.

Take the soundbar or receiver out of the chain

If your box goes into a soundbar or AV receiver and that passes the video on to the TV, you have two HDMI links and two devices negotiating the signal. Plug the box straight into the TV for a test. If the flicker stops, the middle device or its second cable is the weak link. Our guide to HDMI ARC explains how to keep sound going to a soundbar while the video goes straight to the TV.

Change the source's output settings

On the streaming box, console or cable box, check the video output settings. Set the resolution to match the TV, or drop it to 1080p for a test. Vizio also suggests turning HDR off temporarily to see whether it is part of the problem. If 1080p SDR is rock steady and 4K HDR flickers, you have a bandwidth problem in the cable, port or port setting above. Our HDR vs SDR guide covers what each link in the chain has to support for HDR to work.

Flicker that only happens with a streaming box

A short black blink when a video starts or ends is often normal. Many boxes can switch their output to match the frame rate or dynamic range of what you are watching (Apple TV calls this Match Content, other boxes use names like match frame rate). Each switch makes the TV re-sync with the box, and the screen goes black for a moment while it does. If that blink only happens when playback starts or stops, it is the feature working as designed. If it bothers you, turn the matching option off and the box will stay in one output mode.

Flicker on one channel or one app, but not others, usually means that particular stream or app. Close the app fully, check for an app update and try again before changing anything on the TV.

If you are not sure what your box is doing in the chain, our explainer on what a set-top box is covers how it connects and what it outputs.

Fixes when the problem is the TV itself

Turn off energy saving and light sensor features

Energy-saving modes and ambient light sensors change the backlight level on the fly, and on some sets that shows up as pulsing brightness. Look in the picture or general settings for an eco or energy-saving mode and any automatic brightness or light detection option, and turn them off as a test. On Vizio TVs, the company's support article names Ambient Lighting, Backlight Control and Advanced Adaptive Luma as features to switch off temporarily.

Raise the backlight

Many LCD TVs dim the backlight by switching it on and off very quickly. Most people never notice, but some viewers see it as flicker or get eye strain at very low backlight levels. If the flicker is worst in a dim room with the backlight turned down, try a higher backlight with slightly lower brightness or contrast instead.

Power cycle properly

Unplug the TV from the wall (not just standby), leave it for a minute or two, then plug it back in. This clears a temporary software state that a remote power-off does not.

Rule out the power outlet

Samsung suggests a grounding check: unplug the other devices on the same electrical circuit, then play something from a built-in app or USB stick and see whether the flicker stops. TCL gives similar advice to plug the TV into an outlet by itself.

Update the software, then reset picture settings

Check for a TV software update in the support or system menu. If one is available, install it and test again. After that, reset the picture settings to their defaults. A factory reset is the last software step, because it wipes your apps and sign-ins. TCL's support page lists Home > Settings > Device Preferences > Factory Reset for its models with that menu; other brands put it under support or general settings.

Antenna channels only

If the flicker happens only on over-the-air channels, the signal may be weak. LG TVs show signal strength under Settings > All Settings > General > Channels > Channel Tuning > Manual Tuning on 2022 and later models (on 2021 and earlier sets, Channels sits directly under All Settings). LG says a signal strength of 50%, or strength and quality both under 70%, counts as very weak. The LG flickering troubleshooting page has the full path for each model year.

Quick diagnosis table

What you see	Most likely cause	First thing to try
TV menu or picture test flickers too	Inside the TV	Energy saving off, power cycle, update, then service
Menu is steady, HDMI picture flickers	Cable, port or source	Reseat or swap cable, try another port
Black blink when a video starts or stops	Box switching frame rate or HDR mode	Normal, or turn off match content on the box
Flicker only in 4K HDR, fine in 1080p	Not enough HDMI bandwidth	Better cable, enhanced HDMI setting on that port
Flicker only through the soundbar	Middle device in the chain	Plug the box straight into the TV
Flicker only on antenna channels	Weak signal	Check signal strength, reseat antenna cable
Part of the screen or lines flicker	Backlight or panel hardware	Warranty or repair

When flickering means a hardware fault

If the TV's own menu or picture test flickers after you have reset the settings and updated the software, the cause is almost certainly inside the set. The usual suspects are a failing LED backlight strip, the power board, or the board and ribbon cables that drive the panel. Flicker in only one section of the screen, or flicker that gets worse as the TV warms up, fits this pattern.

Check the warranty before anything else, and contact the manufacturer with your model number and what the picture test showed. Do not open the TV yourself unless you know what you are doing: power boards can hold a dangerous charge even after the TV is unplugged.

Frequently asked questions

Why does my TV look like it is flickering?

The most common causes are a loose or underpowered HDMI cable, an energy-saving or light sensor setting changing the backlight, the source switching output modes, or a failing backlight. Open the TV's own menu while it flickers: a steady menu points to the source or cable, a flickering menu points to the TV.

Can a bad HDMI cable cause screen flickering?

Yes. A loose, damaged or older cable can drop the signal briefly, which shows up as flicker or black blinks, especially with 4K and HDR content. Reseat it at both ends, then try a certified high-speed cable.

Does unplugging a TV reset it?

Unplugging it for a minute or two clears temporary software glitches, which is why it is worth trying. It does not change your settings or remove apps. A factory reset, done from the settings menu, is what returns the TV to its original state.

How do you tell if a TV is going bad?

Signs of a hardware fault include flicker that also appears in the TV's own menu or picture test, flicker or dark patches in one part of the screen, lines on the panel, and problems that get worse as the TV warms up. If settings changes and a software update do not help, it is time for the warranty or a repair service.

Why does my TV flicker only when I use my streaming box?

Either the connection to the box is unstable (cable, port or the enhanced HDMI setting) or the box is changing its output. A quick black blink when a video starts is often the box matching the frame rate or HDR mode of the content, which is normal. Constant flicker is worth testing with a different cable, a different port and a 1080p output setting.

If the flicker stops but the picture goes completely black while the sound keeps playing, that is a different problem, covered in our guide to a TV with sound but no picture.