Thick Black Line On Samsung TV Screen [5 Easy Solution]

TV’s mainboard failure, integrated circuit malfunction, faulty bottom buffer board, defective screen and, processing board, and TV panel’s poor connection are mainly responsible for the thick black line on the Samsung TV screen. The thick black line may appear in a different format on your TV screens, such as vertical or horizontal lines, or single or multiple lines.

So, we conducted in-depth research in this article and found out all the major factors responsible for creating these issues. We also described the effective step-by-step solutions for each trouble.

So, by going through this article, you will undoubtedly learn how to fix your Samsung TV screen’s thick black line problems by yourself.

Thick Black Line on Samsung TV Screen [5 Easy Solution]

The vertical or horizontal thick black line on your Samsung smart TV screen is quite annoying. The main factors responsible for creating problems and their solutions are the following:

Note: You can also read how to fix Rolling horizontal lines on TV screen TCL problem.

1. TV’s Main Board Failure

The failed mainboard is one of the main reasons for the black line on the left side of the Samsung TV. The mainboard acts as a power supply source for the TV.

Thus if there is anything wrong with the power board, you may experience a single vertical line on the TV screen. The main reasons for it are:

  • The power supply board’s electrolytic capacitors failed
  • Dry joints within the board
  • Loose connection
  • The damaged mainboard itself
  • Voltage fluctuation or electrical surges or spikes
  • Dust and debris build up with the board
  • Swollen, warped, or burned areas within the board


Repairing the malfunctioning power board is the prime solution to this issue. But before that, remove the TV’s backset and check the main panel to see whether it is the culprit or not. The other fixing ways are:

  • Replace the damaged electrolytic capacitors on your TV’s power supply board
  • Tighten the loose connection and check for the dry joints
  • Replace the defective main board
  • Repair the circuit board and make sure your home’s electricity is stable and there is no voltage fluctuations issue
  • Properly clean the dust, dirt, and debris from the board
  • Check for the burned or warped areas and replace the burnt board

2. Faulty Integrated Circuit

So are you wondering “why is there a thick black line on my TV screen?” Don’t wonder! The defective IC (Integrated Circuit) is the major culprit for this trouble.

IC is a small chip made of silicon or semi-conductor material, but it is one of the main essential parts of the TV. The accountable factors for its failure are:

  • IC exposed to excessive current levels and voltage due to electrical overstress
  • Physical damage
  • Power supply faults
  • IC’s incorrect placement
  • Overheating within the TV
  • Manufacturing defects


If you find that a defective IC is the main culprit for a single vertical line on the TV screen, then you should follow the solutions below:

  • Check the power supply board or circuit board and resolve the electrical overstress issue by replacing the faulty board
  • Replace the physically damaged or manufacturing defective IC
  • Make sure the ICs are correctly placed in the TV’s mainboard
  • Ensure your TV is not overheating due to excessive voltage or electrical surges

3. Defective Bottom Buffer Board

The thin board within your TV uses ribbon cables running across its bottom. And the wires are connected to the bottom panel.

Now you may experience the thick black horizontal line on the Samsung TV screen because the bottom panel or buffer board is faulty. The causes of it are:

  • Misplacement of ribbon cables
  • Damaged or corroded ribbon cables
  • Broken or damaged bottom buffer board


Attempt to fix the above issues carefully following the solutions below. While attempting to solve the faulty buffer board problem, be careful as the retainer plugs may break very quickly. The solutions are:

  • Properly place or reseat the ribbon cables
  • Replace the corroded or damaged ribbon cables
  • Buy a new corresponding buffer board to replace the old one
  • If you are uncomfortable taking apart the buffer board, take an expert’s help

4. Screen Malfunction

Your TV’s screen malfunction is mostly or 95% responsible for the thick black horizontal line on the Samsung TV screen. 

The messing up of your TV screen leads to this black thin line issue. The leading factors responsible for it are:

  • The screen is getting a weak signal
  • Faulty connection from the electrical outlet to the cable box, and from the cable box to the TV
  • Wrong input on the screen
  • Power surges hit the TV screen
  • Screen’s damaged components
  • Faulty power supply board or main circuit board
  • Cracked or broken screen


If your TV’s screen looks unnatural and you see a thick black line on the screen, you should follow the detailed solutions below to know how to get rid of black lines on TV. The fixing ways are:

  • Make sure your Samsung TV screen is getting the proper signal
  • Ensure tightened and adequate connection from the electrical outlet to the cable box and from the cable box to the TV
  • Make sure your TV screen is getting the correct input, and the screen setting is perfectly ok
  • Ensure the voltage stability in your home and check the power surges issue
  • Repair or replace the defective circuit board
  • Replace the broken or cracked screen

5. Poor Connection Between the TV Panel And Processing Board

Usually, the thick black vertical line on the Samsung TV screen results from the improper connection between the panel and the processing board.

The flat ribbon cables connect the processing board and panel by going to the TV panel. Therefore, if there is a connection issue, you will see the vertical line on the TV screen. The leading causes of this are:

  • Flat ribbon cables are not working correctly
  • Loose ribbon connector
  • Damaged electrodes inside the board
  • Corroded or damaged ribbon connector drivers
  • Powerboard is not providing proper power to the screen
  • Failing LCD panels


Remove the TV set’s back to ensure the proper connection between the TV panel and the processing board. And then check the flat ribbons that are connecting these two. The other fixing ways are:

  • Remove the flat-ribbons cables and then re-insert them
  • Tighten the ribbon connector
  • Replace the board’s damaged electrodes and corroded ribbon connector drivers
  • Ensure your Samsung TV screen is getting proper power from the central processing board
  • Inspect the failed LCD panels and replace them


How do I reset my Samsung TV?

Turn on your Samsung TV and go to the “General” option. Now select “Reset” and input the default “0000” pin and then again “Reset” it. Press OK to complete the resetting process. Automatically your TV will restart.

How do I reboot my Samsung Smart TV without the remote?

To reboot your Samsung TV without a remote, first, find out the TV’s back or front control buttons. Then press it. The control buttons are located at the front or back, depending on the TV’s model. After pressing the buttons, your TV will reboot automatically.  

Can you fix a TV screen with lines?

Yes, you can fix your TV screen with dreaded vertical lines. But you may have to pay a higher cost for it. Sometimes replacing the entire TV proved more cost-effective than fixing it.


Now all the reasons are clear to you for why you may experience the thick black line on the Samsung TV screen. If your TV screen suddenly looks unnatural or you see any vertical or horizontal single or multiple thick lines on your TV, you will hopefully fix the issue by yourself.

Still, if you are struggling to resolve it, just comment and let us know. You will get the solution ASAP.

About Gonzalez

William Gonzalez is a passionate researcher & electronics expert who is dedicated to solve complex electronic issues. Plus, he has a passion for sharing his knowledge & expertise in this field with others. Well, he breaks down the complex technical concepts into simple terms & shares them with his readers so that they can easily troubleshoot the problems with their electronic products as well as save their pockets.

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