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Why does my LG TV have blue lines?

As an frustrated LG TV owner, I recently experienced an issue with my television where a blue line appeared on the screen. After some research and testing, I’m here to share how I solved the problem as well as other solutions I discovered.

The most common causes of the blue lines issue on LG TVs are loose or blocked cable connections, visual screen or component damage, or a faulty t-con board. 


  • Blue lines on LG TVs can be caused by loose cables, material or debris cable disruption, damage, or a faulty t-con board.
  • To fix the blue lines, first check the cables, then check for damage, try changing the TV settings, tap the back of the TV, run a picture test, and reset the TV to factory defaults.
  • If the blue lines still appear, the t-con board could be to blame and will need to be replaced.
TopicBlue Lines on LG TVs
Common causes of blue linesLoose or blocked cable connections, visual screen or component damage, faulty t-con board
How to fix blue linesCheck cables, look for damage, change TV settings, tap the back of the TV, run a picture test, reset TV to factory defaults, replace t-con board if necessary
Loose cablesPoor connection to TV from another device; less likely if blue lines appear while streaming content online
Material or debris cable disruptionDebris, dust, or other material interrupting connection; clean connector piece before reconnecting
DamageDamage to screen or unit due to impact from object or floor; backlighting component or screen could be damaged
Faulty t-con boardGenerates vertical and horizontal timing panel signals; could cause blue lines to appear
How to fix loose cablesCheck both ends of video cables for looseness or material blocking connection
How to fix damageConduct visual search for damage; damaged component will need to be replaced
How to change TV settingsSwitch TV input to different HDMI port; rule out different ports
How to tap the back of the TVSometimes causes internal componentry to reconnect if loose; if it briefly works but lines reappear, t-con board may be faulty
How to run a picture testCheck if display is corrupted; find in settings menu along with support or troubleshooting option
How to reset to factory defaultsTry testing TV settings to their factory defaults

Why does my LG TV have blue lines?

Below are likely reasons why your LG TV has been experiencing blue lines.

Loose cables

A common reason for blue lines is that there are loose cables connected to the TV. Loose cables can result in a poor connection to the television from another device. If you’ve shifted around your TV, this could be the reason you’re experiencing blue lines.

Loose cables are less likely to be the cause if there are blue lines when you are streaming content online.

Material or debris cable disruption

Another common reason is debris resulting in an interruption to the connection.

Debris, dust, or other material can interrupt the connection, so it’s also important to clean out the connector piece before reconnecting the cable and television.

Don’t forget to check the other end of the cable as well.


Another possible cause is that the TV is actually faulty.

Damage to the screen or unit due to impact from an object or the floor is one of the leading causes of anomalies.

The backlighting component inside your set provides the screen with light, so if it gets damaged or blocked, the light will only shine through on certain lines.

Another part that could be damaged is the screen. If it absorbs some sort of impact, it can cause a variety of line colors to appear, including blue.

Faulty t-con board

An LG T-con board generates the vertical and horizontal timing panel signals while enabling signals and providing panel boas.

This component looks like a computer motherboard and controls the logic gate signal and serves as the source for propelling the thin-film transistor (TFT) LCD.

Since this component directly controls the vertical and horizontal signals, it could cause blue lines to appear.

Read more: Why is my LG TV blurry?

How to fix the blue lines on an LG TV

The blue lines could be a simple or complicated fix, depending on if there’s damage to any part of the television.

However, below are the options you have when getting rid of them.

Check the cables

The first step you should take is to check both ends of all video cables.

As mentioned earlier, the connections could be loose, especially if you recently shifted around the television, or could have material blocking the connection between the cable and the LG TV input or set-top box output and cable.


Next, conduct a visual search for any damage that could be present. If the LG TV has recently fallen on the ground or sustained some form of impact, then you want to

Television settings

If the root cause isn’t damage or loose cables, try changing or resetting your LG TV’s video settings.

Start by switching the TV input to a different HDMI port since the one you’re using could be defective or damaged.

This may also help rule out different ports. Remember to switch the input on the television as well so you don’t receive a “no signal” error.

T-con board

While this might seem like an outdated gesture from the analog antenna days to get the picture to show but give the back of your LG TV a tap.

This sometimes causes the internal componentry to reconnect if loose. If it briefly works but lines reappear, then you may have problems with your T-Con board.

Once the T-con board is damaged, faulty, or has an issue, it will need to be replaced to ensure a properly functioning television.

Picture test

Many modern LG TVs have an integrated feature that allows you to see if your display is corrupted.

Different LG TV models have different interfaces that display this information, but you can usually find this function in the settings menu along with a support or troubleshooting option.

Some models just have a picture test option that provides the results. This is a crucial step if you’re planning to contact technical support.

Reset to factory defaults

It would also help. to try testing the settings of your TV to their factory defaults.

Read more: Why is my LG TV overheating?