TCL TV Backlight Not Working (3-Min Troubleshooting)

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TCL TV backlight problems are particularly common if you have been running your backlight too hot at 100% brightness since purchase.

Backlight problems are usually caused by a single burned-out LED which causes a voltage increase to the remaining LEDs on the strip and makes those pop too, taking your backlight offline.

But there can also be power board issues that mean the backlight isn’t receiving power, or even T-Con issues that make it look like your TCL TV or TCL Roku TV backlight is not working.

I’ll cover the most common TCL backlight problems in this troubleshooting guide and include tips on backlight replacement and repair.

Possible Causes of a TCL TV Backlight Not Working

Backlight Failure Cause
Failed T-Con Board or Connection A poor connection of the LVDS cable connecting the T-Con to the main board or damage to the cable’s pins will result in no picture on your TCL TV.
Power Board Burned Out Component Overvoltage or wear over time can cause component burn out on the power board which can be identified by burn marks on the board itself, or by using a multimeter.
Dim Images Equal LED Failure When the individual LEDs in the backlight fail, you will see very faint images when you shine a light on your TV screen. To fix this, you need to replace the backlight LED strips.
Failed LED Diffusers Diffusers coming loose from the LEDs cause bright patches on your screen that look like backlight failure. You can simply glue these back on to fix your backlight.

3-Minute Troubleshooting for TCL Backlight Problems

TCL TV backlight issues can be fixed by replacing any failed components on your power board or by replacing your backlight strips where any individual LEDs have burned out.

You can watch a quick overview of the fixes in my short video below, with more detail on each in the rest of this guide.

How to Diagnose + Fix Backlight Issues With TCL TVs

1. TCL TV Backlight Issues With No Picture

tv half screen dark

If you are seeing a half dark screen on your TCL TV, or you know that the backlight is working but you have no picture, then this is most likely not a backlight issue, but is instead a problem with the timing control or T-Con board, and specifically is often a sign that there is a failure of the LVDS cable connecting the T-Con board to the display panel itself.

The T-Con board is a small PCB board that drives your TV’s panel, sending the signal to each pixel row of your screen using internal clocks to keep each row in sync.

TCL tv t con board

Either the LVDS cable connectors can come loose or get covered in grime or dust, preventing a clean contact or components on the boards can fail, meaning they don’t power the backlight sufficiently or cannot provide a constant picture signal.

To access the boards, first remove the back panel. If you’re not confident doing this, then now is the time to get an expert. 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 back panel. 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 board for translating the signal into a TV picture, a power board, and a main board.
tv internal boards

It’s a good idea to start your investigation with the T-Con board, as one or more of the internal clocks failing is a regular cause of TV screen problems.

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.

TCL tv t con ribbon cables

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 ribbon-like low voltage differential signaling (LVDS) 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 the LVDS cables out without unlocking them first.

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

After removing the LVDS 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 LVDS cable in good condition

If cleaning and reseating the cables does not fix the picture, then you most likely need a new T-Con.

T-Cons can be bought for around $30 from eBay – just search for your TV’s model number.

See how to replace a T-Con on a TCL Roku TV in the video below.

Read More:

Every possible fix for the half screen dark problem with TCL TVs

2. Look for Burned Out Components

The power board/main board is often the problem if your backlight is flickering or your TCL TV won’t come on at all.

You need to open up your TV as before and identify the main board and power board, which will be in addition to the t-con board that we have already looked at.

The Main Board is a larger PCB where you plug your HDMI and other connectors into. This does a lot of the work of translating the input into signal, which then goes to the T-Con board.

TCL tv main board

The Power Board is where you plug in your power cable, and it converts your home electricity supply into a voltage and current that your TV can use.

TCL tv power board

You will then need to find the ribbon cable that powers your backlight (either via a voltage inverter or directly to the backlight), which will be connected to your power board.

Look for any signs of damage or burning, and check that the connector is firmly in place.

Take a look at the video below for a good look at how to troubleshoot your power board using a multimeter.

If you need to, it’s much easier to replace the entire power board rather than any individual components (unless you happen to have those components lying around).

You can get new power boards for between $30 – $50 from eBay.

You can see how to do this in the video below.

3. Check for LED Failure

Older TV models have a backlight inverter that powers the backlight of your TV by uprating the standard voltage and current of your home supply to the higher levels required by the backlight.

More recent TVs integrate this onto the power board.

An error message relating to a burned-out LED in the backlight, which is sent from the voltage inverter to your main board will often cause your TV to turn on and off repeatedly.

tv inverter board
A typical separate voltage inverter on an older TV.

To check for backlight failure:

  1. Follow your normal process for switching on your TV.
  2. Get right up close to the screen and point the light on your phone or a flashlight directly at the screen.
  3. Try changing channels with your remote, or going into the menu.
  4. If the backlight is the only part not working, you will see very faint images on your TV screen.
shine a flashlight on your tv screen and if you see faint images then you have a failed backlight
Shine a flashlight on your TV screen and look for faint images

If you see faint images, you can be pretty certain that the backlights themselves are the failure point in your TV.

You can see this process in the video below.

Flashlight Test Result Explanation
Faint Images Most likely a backlight failure.
No Faint Images – If the backlight is working (screen is “glowing”), you most likely have a T-Con issue.
– If the backlight is not working, you most likely have a main board issue.

Backlights on modern TCL 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.

TCL tv led backlight

These cold soldered connectors are a notorious failure point on TCL 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 overpowering, which over time causes thermal degradation of the LEDs leading to burnout.

You can replace any failed LEDs by ordering new strips for your TV model from eBay (approx. $30) and switching them over yourself.

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.

standard tv backlight
Standard TV backlights in horizontal strips

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 or TV backlight tester to test the backlight strips to find out where the problem lies.

Assuming you have followed the steps to check the T-Con, Power, and Main Boards, you now need to:

  1. Any wires or ribbons that are near the edge of the TV should be disconnected.
  2. Then remove the screws around the edge that hold the bezel of the TV.
  3. With some care, you should be able to remove the bezel and panel and reveal the TV backlight underneath, which will be in strips of LED lights.
  4. Use a voltmeter or TV backlight tester to check whether they are working, and replace any failures.

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.

4. White Spots Are Failed Diffusers

TCL tv led backlight problems

Bright spots are very common on TCL TVs older than two or three years.

This is because of the design of the LEDs used in the backlight and the fact that the glue holding the reflector over the LED can burn off over time, causing the reflector to fall to the bottom of the panel.

The basic design of these backlight LEDs is that they come in strips of LEDs with a lens over each LED to diffuse the light and make sure there are no hot spots, but just a general glow.

tv led reflector

You can see a set of working LEDs with reflectors in the image below, and you can see the circular reflector covering the LED diffusing the light.

tv backlights

With TCL LEDs specifically, the glue holding the reflector on can fail, usually caused by thermal degradation from the LED itself.

This means that the light from the LED is no longer being spread out, and creates a hot spot of white light on your TV.

You can tell if this is a problem if you can hear something rattling inside the bottom of your TV’s case when you move it.

This rattling is the fallen reflectors.

The easiest way to deal with this is to open your TV up, carefully removing the back panel and internal components until you uncover the backlight LED strips.

You should see one or more LEDs without reflectors which correspond to the position of the white spots on your screen.

tv backlight led without reflector

The reflectors/diffusers themselves should be at the bottom of the TV’s case, and they most likely would fall out when taking your TV apart.

tv led backlight reflector

Most TCL TV backlight diffusers will be connected by three points to the LED strip.

Simply glue the fallen diffuser lenses back over their LEDs using a clear epoxy, and the hot spots on your TV display will be fixed.

  1. Get some toothpicks and clear epoxy. Superglue is not recommended as it is not heat-stable.
  2. Put a small amount of epoxy onto some card or paper if it is pre-mixed, or if not pre-mixed, put each component onto separate parts of your card.
  3. Use the toothpick to pick up some of this epoxy (mixing both components if necessary) and carefully apply it to the three points on the LED strip where the diffuser connects.
  4. Carefully place the diffuser back into place on the LED strip and hold it until the epoxy has set.

TCL TV Support and Warranty

It goes without saying that if your TV is under one year old, then you should contact TCL customer support to get it replaced under warranty.

You can call TCL directly at:

  • 1-877-300-8837 (Mon – Fri, 9am – 12am ET, Sat – Sun, 9am – 6pm ET)

Or contact them via email.

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

TCL TV Backlight Not Working Quick Fixes

  • The main cause of backlight issues with standard TCL or TCL Roku TVs are failed backlights where one LED has burned out and taken the entire LED strip with it.
  • These can be replaced at home by opening up your TV and getting a new set of LED strips from eBay or elsewhere for a few dollars.
  • You should check your T-Con LVDS connection if half your screen has gone black.
  • If a multimeter confirms that your LEDs are working normally but you don’t have any picture, then look for failed components on the power board.
  • Bright patches mean that the LED diffusers have fallen off and need to be glued back on.

To prevent backlight issues in the future, remember the reduce the brightness of your backlight, as high brightness and therefore high LED temperature is a common cause of failure.

If you are still having trouble, then I would suggest contacting TCL support or leaving a comment and I’ll see what I can do to help.

Read More:

TCL TV black screen with sound?

TCL TV half screen dark?

TCL Roku TV black screen?

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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