LG's flicker article begins with the smartest test: use the remote to open the settings menu and see whether the on-screen menu displays normally. If the menu is steady, the issue is likely the external device, cable or broadcast signal; if the on-screen menu also flickers, the TV itself may be at fault and LG asks you to contact customer support for inspection. LG lists why the screen flickers: a weak input signal can cause flicker, black screens or glitches; an unstable antenna connection or worn cables; a problem between an external device such as a set-top box and the TV; or internal components.
Turn off the TV and devices, remove the HDMI cable from the back of the TV and reconnect it, and if possible reconnect it at the device. Check the antenna cable for damage or loose connections.
The checks in more detail
Check the broadcast signal strength: on webOS 6.0 and later go to All Settings, General, Channels, Channel Tuning, Manual Tuning and select the antenna to see strength and quality for a channel. LG says a signal strength of 50 percent, or strength and quality both below 70 percent, is very weak, and to contact the building maintenance office or service provider. For antenna viewing the internet is unrelated; for IPTV check the internet.
LG also has an OLED article where the screen flickers with a scratchy sound and one for flicker from the Motion feature; try TruMotion off. Update the software. Record the flicker in slow motion on your phone. A steady rate points at dimming or refresh settings, and an irregular one at the signal or cable, which narrows the fault quickly. If flicker appears only with one device, check that device's refresh rate and resolution before blaming the TV.
Differential
Likely causes of “LG TV line screen flickers, flashes or goes black intermittently”, and how to tell them apart
- 1
A weak broadcast signal
What separates it The picture flickers or goes black on antenna channels because the broadcast signal is weak
How to confirm Improve the antenna, or contact the provider if the signal is weak
- 2
A loose or worn cable
What separates it The picture flickers on one source because the cable is loose or worn
How to confirm Reseat the cable at both ends, or replace it with a new one
- 3
An external device
What separates it The picture flickers only from a box because the external device has a fault
How to confirm Test another device on the same input, to see whether the flicker stays
- 4
The Motion feature
What separates it The picture flickers in motion because the Motion feature is switched on
How to confirm Turn the Motion feature off, and see whether the flicker stops
- 5
Internal components
What separates it The menu flickers too, which points to internal components as the cause
How to confirm Contact LG service, since flicker in the menus points to a fault inside the TV
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the on screen menu flickers as well
- The signal strength and the signal quality of the channel
- The source and the cable that you are using
- Whether it happens on all inputs
Try in this order
0 of 6 completedOpen the settings menu
ReversibleOpen the settings menu, and see whether the menu itself flickers on the screen, and then test again to see whether it helped.
Reseat the HDMI cable
ReversibleReseat the HDMI cable at both ends, and make sure that it is pushed in fully.
Check the antenna cable
ReversibleCheck the antenna cable for damage, such as kinks, cuts or a loose connector, and then test again to see whether it helped.
Turn off the Motion feature
ReversibleTurn off the Motion feature as a test, and see whether the flicker goes away.
Test another device
ReversibleTest another device on the same input, to isolate whether the source is the cause.
Update the software
ReversibleUpdate the software on the TV, and then retest whether the picture still flickers, and then test again to see whether it helped.
Model-specific
What is true of this model and not of its siblings
- OLED
- OLED models flicker differently from LCD models and LG has separate guidance.
- Antenna
- Antenna signal checks apply only to models with a tuner.
- Other models this page answers
- These steps also fit models B3, B5, C2, C3, C5, CX OLED TV, G3, G4, G5, M4, QNED85T, QNED90T, UR9000.
Stop boundary
When this stops being a self-service repair
- !If the menu flickers, contact LG for inspection
- !If signal strength is 50 percent or below, contact the provider
- !If it flickers with a scratchy sound on OLED, see LG's article
Evidence ledger
Sources behind this answer
Menu test, HDMI, antenna and signal strength.
OLED flicker with sound.
Screen and Sound Self-Diagnosis by model year.
Software Update menu.
The company and its products.
Exact questions
Common questions
What is a weak signal?+
50 percent, or both below 70 percent.
Does the internet matter?+
The internet does not matter for antenna viewing, since the signal comes from the aerial.
Can Motion cause it?+
Sometimes, the Motion feature can cause flicker, so turn it off to test.
Where do I check signal strength?+
You check the signal strength under Channel Tuning, in Manual Tuning.
Can OLED flicker with sound?+
LG has an article about OLED flicker that comes with sound, so check its support page.
Should I try another device?+
Yes, try another device on the same input, to see whether the source is the cause.
Can updates help?+
Sometimes, an update fixes flicker, so update the TV and check again.