What causes the TV backlight to fail? (2023)

Backlight failure is a fairly common problem, especially on cheap LED/LCD TVs.

Backlights are the light sources that illuminate the screen to allow images to be seen. Unfortunately, when this fails, the screen goes black and there is no image. Also, with uneven light distribution, you are likely to experience flickering screens, dark and bright sections, and light leakage at the edges of the screen.

Fortunately, troubleshooting a backlight is easy. All you have to do is check and test the backlight system to make sure it really is the cause of the problem. Occasionally, the problem can come from the power supply, motherboard, or power board. Therefore, you should also test and verify them.

Signs that your TV backlight has failed

Before concluding that the backlight has failed, you need to diagnose it. Turn on your TV. Take a flashlight and shine it very close to the TV to see if you can see any pictures. If you see a dark image, it means the backlight has failed.

Below are signs that your TV backlight has failed and needs repair or replacement.

1. Black screen

If you turn on your TV and there is no picture but the sound is on, there is a big chance that the backlight has failed.

Please note that a black screen is different from a blank screen. A black screen indicates that one or more LEDs are defective.

2. Screen-Outfit

If the screen appears unusually dark even after increasing the screen brightness, the backlight has probably failed.

A dark screen is hardly noticeable, especially during the day. Natural light from outside or light from incandescent bulbs will mask the screen's faint light and make viewing impossible. Instead, you are forced to stare into a dark room.

3. Screen flickers

A flickering screen is an indication of a dying backlight strip. In some cases, the screen may work fine and then suddenly turn off after a few minutes or start flickering out of the blue.

4. Dim screen

This is when half of the screen is dark while the other half is working fine.

This often happens when the LEDs on one side of the backlight strip are working properly while the LEDs on the other side are faulty. Half screen can mean the left or right side is dark, or the top or bottom half of the screen is dark.

5. Dark spots

Sometimes you will find that areas on the TV screen are dark.

This usually happens when some LEDs don't light up even though they still conduct electricity, while others are working fine. Areas with defective LEDs appear dark, while areas with working LEDs are bright.

6. Blue screen

A blue screen is the rarest form of backlight failure. In this case, the LEDs emit a blue light instead of the usual white light, which makes the screen appear blue.

7. Bright spots

This often occurs when the lens detaches from the backlight LED strip.

If you try to move the TV, you'll even hear the lens moving in the panel. If you look closely you can even see the lens on the bottom of the TV.

What causes the TV backlight to fail?

Sudden power surges, physical damage, moisture/water, and defective backlight bulbs are some of the possible reasons for backlight failure. In many cases, the most common culprits are burned out LEDs or faulty backlight controller boards.

Let's take a closer look at these causes to understand exactly how they lead to backlight failure.

1. Sudden surge/high voltage

A surge is a sudden increase in voltage. It occurs when a high electrical current (exceeding the recommended rating) flows through a circuit.

When this happens to a TV, the circuits associated with the electrical components are destroyed. Unfortunately, this includes the backlight.

Voltage spikes can cause LEDs to burn out and short out the LED driver circuitry, preventing current from reaching the LCD panel.

A power surge, no matter how small, can damage the backlight, especially if it occurs frequently.

Surges can be caused by household appliances such as power tools, washing machines, and ovens. It can also be caused by external factors such as lightning.

To avoid damage to your TV from surges, I advise you to invest in a good deviceHigh-quality surge protection for televisions. a powervoltage protectionIt protects your TV from high voltages coming from internal or external sources.

2. Poor LED backlight

LED lamps in a backlight strip are designed to have a finite lifespan, especially with continued use.

So at some point you will have to replace them. However, this may still be more than 10 years later.

LED lamps can also fail due to high voltage or extremely high brightness, resulting in high temperatures. If LEDs generate too much heat, they can burn out.

Once the LED backlight bulbs are damaged, they must be replaced in order for the TV to function properly again. Luckily, LEDs are inexpensive and don't require much expertise to replace.

However, since the LED bulbs are connected in series, you will have to replace the entire strip. So if one becomes defective, it affects the rest. Bad light bulbs make the screen very dim or have dark spots.

Check out this tutorial video below from Repo Apps. Sample for diagnosing and repairing defective LED lamps.

3. Defective LED driver board

You should also fix the LED driver circuit.

There is a possibility that the LEDs are not receiving enough voltage and current. In this case, the LEDs can be damaged.

4. Faulty inverter

Another possible reason your TV backlight system has failed is a faulty or faulty inverter or capacitor. The solution to this is to replace the inverter.

Watch this video for instructions on how to replace the inverter.

5. Defective power board

Sometimes the electrical traces on the board can be faulty. This prevents enough power from being directed to the backlight system, resulting in a dim display.

6. Physical Damage

Physical damage such as B. Fall damage can cause LED strips to slip. This results in uneven light distribution across the panel, hence the dark and light spots. Drop damage can also cause the lens to slip.

7. Water damage

Water is one of the biggest enemies of any TV.

If the TV comes into contact with even a little water, it seeps right through the hardware and into the electrical components.

Two things can happen: you could short out the circuit board and/or corrode the metal vias. All this leads to a failure of the backlight.

Can TV backlights be replaced?

Yes, the TV backlight can be replaced.

However, I wouldn't recommend trying it yourself unless you really know what you're doing.

We recommend that you leave the replacement to the TV technicians if you are inexperienced in this type of work.

Otherwise it is not a complex process. You will need a soldering iron, a screwdriver, wires and flexible LED strips. Just make sure you buy a backlight replacement that is compatible with your TV model.