LG TV Half Screen Dark: Fix in Minutes

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A few years into owning your LG TV, you might see half of the screen going dark, you might have half screen black and half screen white or the top half of your LG TV might be darker.

These problems are all very common, and all have the same basic causes, but it doesn’t mean that you have to get an expensive new model, as LG support might suggest.

Instead, you can easily fix LG TV half screen dark problems at home, with just a little know-how and some effort.

In this article I’ll guide you through every possible fix to help you get your TV back up and running again.


lg tv half screen dark

LG TV Half Screen Dark

Fix an LG TV half screen dark by either replacing any failed LED backlights or re-soldering any faulty connections between LED strips, or by adding strips of tape to the ribbon cable connecting the T-Con board to the panel to block any faulty clock signals.


Because people mean different things by “LG TV half screen dark”, or “LG TV dark on one side”, the issue can be caused by a couple of different problems, both of which have different solutions.

For example, a dark band across your LG TV is caused by a backlight issue, while either the left or right hand side of the TV screen being totally blank is likely a T-Con issue.

We’ll cover every possible fix below, but make sure you read the description for each carefully so that you can match the correct fix to your exact problem.


1. Power Cycle Your TV

With modern electronics, it’s possible that the half dark screen on your LG TV is caused by something stuck in your TV’s flash memory, which can also be a problem if you are seeing vertical lines on your TV.

Power cycling your TV will clear out any issues with non-permanent memory and reset your main board without losing your personal settings.

This is quick and painless and won’t cause you to lose any of your saved settings.

  1. Switch off and unplug your TV.
  2. Hold down the physical power button on the TV for at least 15 seconds.
  3. Wait for at least 30 minutes for any residual power to drain from the TV’s capacitors (which are capable of storing charge for several minutes).
  4. Plug your TV back in and try switching it on. You should see a red light if you have been successful.
lg tv power button
LG TV power buttons are often on the side of the TV

Make sure you do wait for the full 30 minutes before plugging your TV back in – you would be surpised how long the components within your TV can hold charge, and you want to make sure it has fully reset.

Although this seems a very basic step, don’t overlook it because in the vast majority of cases a simple soft reset fixes most issues.

Most people will now have their TV fixed and back up and running. If this isn’t you, then we’ve got a few more basic fixes to try before getting into the hardware fixes.


2. Unplug Your HDMI Cables

There’s a strong possibility that a poorly seated cable is creating signal noise which is displaying as a half dark screen, and is also a common cause of purple tints on LG TVs.

This comes down to either a:

  • Faulty HDMI cable with a break in it
  • Damaged HDMI port with broken pins
  • Poor HDMI connection where the cable and connector are not fully making contact
tv hdmi cable

To check your HDMI and other cables:

  1. Switch off your TV.
  2. Remove any HDMI or other physical cables connected to the back of your TV.
  3. If you have any compressed air, use that to clean the contacts both of the cable and in the connector on the TV. If you don’t have compressed air, then blow gently on them.
  4. Firmly push the cables back into their slots on the TV.
  5. Switch your TV back on again.

It that hasn’t fixed the problem, then try using a different HDMI input. Most TVs have 3 or 4 HDMI ports.

If you have one that is on a different part of the TV then that would be the best one to try, as it this should have a separate connection to the TV’s main board.

lg tv hdmi port

Plug you HDMI cable into the new port, note the number next to it, then choose this HDMI input on your TV, by using the Input or Source button on your TV remote or the Input or Menu button on your TV itself.

lg tv remote input button

You can also try removing all external devices, including those connected by Bluetooth and any coaxial or signal cables, so that the TV only has a power cable going into it.

When you turn your TV on, this means the screen will be black as it is not receiving any picture, potentially making it tough to see if half the screen is working or not.

Pull up the on-screen menu to see if half the screen is still dark. If it is, this means that your external connections are fine and the problem is located within the hardware of your TV.

If the screen is uniformly bright, then try re-seating your HDMI and other cables one by one, until you find the damaged cable that needs replacing.


3. Confirm Your Wall Socket is Properly Supplying Power

Because flat screen TV’s rely on a constant power supply, when there are fluctuations in voltage these can show up as inconsistencies with the backlight, causing dark areas on your TV.

If your TV is on, then you know that your wall socket is suppplying power, but the question is whether this is constant without fluctuations and is of a sufficient voltage.

The most common cause of low voltage from wall sockets are faulty surge protectors.

unplug your tv

If you don’t have a wall socket testing rig, then just unplug your TV, remove any surge protectors and try another appliance that you know draws a similar current. Check if this works as expected.

You can also plug your TV into another wall socket, preferably one located on the other side of the room from the current socket, again without any surge protectors or consumer extension cords that you might be using.


4. Update Your TV’s Firmware

Software and firmware issues have been known to cause problems with the display on LG TVs.

As with any product, you should ensure that you have updated your TV’s firmware to the latest version, even if it is new.

Smart LG TVs support auto-updating of firmware, but you can’t assume that this is turned on for you.

To check that auto-updating is on for firmware / software on your smart LG TV:

lg tv remote settings button
  1. Press the Settings button on your remote and go to All Settings.
  2. Click Support.
  3. Then Software Update.
  4. Agree to any terms and conditions that may popup, then switch on Auto Update if off.
  5. You can also manually check for updates here.
lg tv auto update screen

For older LG TVs:

  1. Press the Settings button on your remote and go to All Settings.
  2. Go to General.
  3. Then About This TV.
  4. Check Auto Updates are on, and use the Check for Updates button to manually see if you are running the most recent firmware version.
lg tv usb firmware update

For some LG TVs, you’ll need to update the firmware by USB. To do this:

  1. Go to the LG Software Drivers site.
  2. Enter your TV’s model number and find it on the site.
  3. Put a USB stick into your computer and create a folder on it called LG_DTV.
  4. Right-click the firmware ZIP file on LG’s site and Extract All to the folder on your USB stick.
  5. Once complete, eject your USB stick.
  6. Insert the USB stick into your TV’s USB port and switch it on.
  7. The TV will automatically search for the folder you created and should display USB UPDATE READY.
  8. Select Install.
  9. Follow the on-screen instructions, then switch off your TV for 10 seconds and power back on to complete the update.

5. Change Your Picture Settings

Most LG TVs have an option to change the color temperature or other aspects of the picture.

Using your remote control, press the Settings button, then All Settings and go to the Picture menu.

lg tv picture menu

You can try the various picture modes to see if they fix the half screen dark issue, and you should also switch off Energy Saving mode, as well as changing the Panel Brightness and Gamma.


6. LG TV Factory Reset

Returning your TV back to its factory settings is a more extreme step, as it will delete any personalization features, downloaded apps or connected devices, but it’s always worth a shot when other methods haven’t worked.

To factory reset an LG Smart TV:

  1. Press the Home button on your remote and go to All Settings.
  2. Then General.
  3. And System (or skip to the next step on older models).
  4. Choose Reset to inital settings.
  5. Follow the on-screen instructions and hit Confirm.
  6. Enter your PIN, which by default is 0000 (four zeroes) or 1234 for LG.
  7. Then select Restart in the popup.
lg tv factory reset

If you don’t have your remote, then to reset an LG TV:

  1. Hold down the TV’s Power Button for 10 seconds, which will be underneath the screen on on the side.
  2. Use the Vol + or – or Channel + or – to scroll to Menu.
  3. Go to All Settings.
  4. Then General.
  5. And Reset.
  6. Follow the on-screen instructions and hit Confirm.
  7. Enter your PIN, which by default is 0000 (four zeroes) or 1234 for LG.
  8. Then select Restart in the popup.

If you have changed your LG TV’s PIN and can’t remember what it is:

  1. Press the Home button on your remote and go to All Settings.
  2. Then Support.
  3. Go to Advanced Settings.
  4. Then Safety.
  5. And Reset Password.
  6. On your remote, press Channel Up twice, then Channel Down once, followed by Channel Up once.
  7. Put 0313 in the box.
  8. Then 0000.
  9. Then choose a new PIN that you can remember.

That should solve most dark screen issues without you having to delve into hardware problems, but just in case you still have a problem then this will be caused by the backlights, which will need replacing.


7. Check Backlight for Dark Areas On Screen

lg tv screen darker than normal

If you are seeing dark areas on screen, or either the top half, bottom half, left side or right side is darker than its counterpart, or your LG TV screen is darker than normal, then you have a backlight issue.

Backlights on modern LG TVs come in LED strips of varying lengths. Older models used lengths that spanned the entire frame of the TV, but due to cost savings, more recent TVs use a set 16″ LED strip which is connected in series for each row to span your TV.

These cold soldered connectors are a notorious failure point on LG TVs, but can be easily fixed if you are willing to re-solder a joint yourself.

Equally commonly, the LED backlights themselves can fail. This is due to repeated current over powering, which over time causes thermal degradation of the LEDs leading to burnout. You can replace any failed LEDs by just removing the entire strip and replacing it.

The problem with fixing the LEDs is that they are located in the most difficult to access part of your TV. So if you are not comfortable with a larger repair job, then now is a good time to seek help from a professional.

You need to remove the back panel, remove all of the circuit boards and connectors, then another layer of screws for the front panel, and only when you have fully removed the LCD panel can you get to the backlights.

You will also need a multimeter to test the backlight strips to find out where the problem lies.

tv led lights
Replacement LED backlight strips

To fix a failed backlight:

  1. Unplug your TV, hold down the power button and wait for at least 30 minutes. There are large capacitors in the power board for the backlight and these can hold charge for an extended period of time.
  2. Place your TV face down on a large table or workbench. Make sure there is nothing that can scratch the screen on your work surface.
  3. Ground yourself.
  4. Open your TV by unscrewing the screws in the backpanel. It should come apart in two pieces: front and back.
  5. Put the back panel somewhere out of the way and take a look at the circuit boards that have been revealed.
  6. You will see a T-Con panel for translating the signal into a TV picture, a power board and a main board. Any wires or ribbons that are near the edge of the TV should be disconnected.
  7. Then remove the screws around the edge that hold the bezel of the TV.
  8. With some care, you should be able to remove the bezel, panel and reveal the TV backlight underneath, which will be in strips of LED lights.
  9. Use a voltmeter or TV backlight tester to check whether they are working, and replace any failures.

The video below covers checking and replacing the LED backlights, with some additional tips on when you should seek to replace your backlight driver board instead.

It’s also possible that one of the connectors linking the LED strips as they span the width of your TV has failed. This can be fixed by checking the connectors with a multimeter and re-soldering and broken connections. This article has a good study on this.

Rarely, the backlight issue can be caused by a faulty main board. You can follow the next step to identify it, clean the contacts going into it and replace it if necessary.


8. For Half Your Screen Being Black, Check Your T-Con Board

If either the left or right hand side of your LG TV screen is totally black, extending from the edge to the center or your screen, then there is a problem with your T-Con board or the cabling connecting it to your screen.

The Timing Control (T-Con) board is a small PCB board that drives your TV’s panel, translating the signal into a picture on your screen.

It’s hidden away under the back panel, behind the screen, and is the cause of a half black TV screen because it connects to the LCD / OLED panel with ribbon connectors which can come loose or get covered in grime or dust, impeding their contact.

vizio tv t con ribbon cables

To access the T-Con board, you need to remove the back panel. If you’re not confident doing this, then now is the time to get an expert in. Otherwise:

  1. Unplug your TV, hold down the power button and wait for at least 30 minutes. There are large capacitors in the power board for the backlight and these can hold charge for an extended period of time.
  2. Place your TV face down on a large table or workbench. Make sure there is nothing that can scratch the screen on your work surface.
  3. Ground yourself.
  4. Open your TV by unscrewing the screws in the backpanel. It should come apart in two pieces: front and back.
  5. Put the back panel somewhere out of the way and take a look at the circuit boards that have been revealed.
  6. You will see a T-Con panel for translating the signal into a TV picture, a power board and a main board.

Or see this in action in the video below.

The position of the boards will vary by model, but the T-Con board can be identified by the ribbon cables connecting it to the TV’s panel. Identify the main three boards you will see in the images below.

tv main board
tv power board
tv t con board

Start by giving everything a good clean, preferably with compressed air or a non-static brush. It’s possible that dust in the connections can block the signal.

Then, you should be able to remove the cables on the T-Con board by pushing the locking cover down and they will then easily come away from the board. Don’t try to force them out without unlocking them first.

removing t con cable
Push the locking bar to remove the T-Con ribbon cables

After removing the ribbon cable, take a look at the individual connectors on the ends of the cables, and the connectors in the socket. You are looking for any signs of corrosion, damage or dust.

The contacts should be a shiny gold or silver color. If they are dull and appear to have a rough, copper-like layer over them, this would indicate oxidation and therefore a new cable is recommended.

t con cable
A T Con cable in good condition

Give the cable and socket a good clean with compressed air, then put the cable back in, put the back panel back on your TV and fire it up.

If half the screen is still black, there’s a good chance that there is a fault somewhere on the T-Con board itself. These can be replaced for around $30 from eBay.

To get the correct board, note the T-Con model number written on the label on the board, and put this into eBay.

But before you replace the T-Con Board, try the final step which can fix faulty boards without you needing to replace them.


9. Block the T-Con Signal with Tape

This might seem like a bit of a hacky approach, but it is possible to use small pieces of non-conductive tape to block the indiviual contacts on the T-Con cable.

This blocks the “bad” signal getting sent through that contact, and can actually clear up the image.

This works because the T-Con cable sends a clock signal through a handful of the pins (usually 8 pins per cable) which is implicated in the most common issues of half your screen going black.

And with two cables, one for each side of the TV, you can use the signal from the working side of the T-Con board to fill in for the faulty clock signals on the other side.

This method can also work well for fixing horizontal lines on an LG TV.

It can take some trial and error to get this right, so I recommend you check out the video below for a good demonstration of how to follow this approach.


LG TV Support and Warranty

You can check your warranty information direct with LG.

Unfortunately, warranties typically only last a year unless you have already paid to extend it.

Although you are unlikely to see a half black screen on an LG TV under one year old, this can happen. If so, return your TV under warranty and get it fixed.

You can use the LG support site to help diagnose your problem, but if you are at this stage, then you are better off calling them direct on:

  • 850-999-4934 or 843-243-0000 (Mon. – Sun., 8am – 9pm EST)

You can also email them directly, or even email the president of LG customer care!

Even if LG won’t fix your TV, they might still offer you a discount off a future model if you pester them hard enough! This is always worth a try in my experience.


Final Thoughts on How to Fix an LG TV With a Half Dark Screen

There are a couple of main causes for a half dark screen on your LG TV, but these can be fixed by following the steps below.

  1. Power cycle your LG TV.
  2. Unplug your HDMI cables.
  3. Confirm your wall socket is supplying consistent power.
  4. Update your firmware.
  5. Change your picture settings.
  6. Factory reset your TV.
  7. Replace any burned out LEDs in the backlight, and re-solder any poor connections in the backlight strips.
  8. Clean and replace the T-Con board if half the screen is totally black.
  9. Block the T-Con signal with tape.

Let me know if this helped in the comments, and let me know if there’s anything else you need help with!


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Follow Tim Daniels:

Hi, I'm Tim Daniels, photographer and photo trainer, founder of Lapse of the Shutter and creator of the totally free Lightroom Develop System. I've travelled to (probably) 30 countries over the last few years, taking photos and licensing them around the world, and creating lots of free photography learning resources. Read More ...

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