Lines On TV Screen

It never hurts to start with the almost insultingly obvious checks, but they're cheap, so let's dive in. Here's the easiest place to start.

• Unplug your TV for 60 seconds. Don't just turn it off.
• Hold the power button down for 30 seconds after it is unplugged.
• Count slow on those 60 seconds or use a watch.
• Plug your TV back in and check for a clear picture. If it's working, you are done.
• If not, go to the next step.

Very occasionally, the issue may be caused by fluctuating voltage in your AC supply. The usual culprit is a surge protector. To check this, plug the TV directly into a wall outlet and see if the problem disappears. If it does, replace the surge protector. If not, go on to the next step.

Some units will have a picture test available which will allow you to check if the problem is internal. If you have Picture Test, turn it on and see if the lines disappear. If they do, the problem is likely one or more inputs, or the main board. You can go to Connections and start in. If the lines are still there, it is likely a hardware problem. If you don't have this go to the next item below.

We are now going to break the problem down into pieces and then start.

Some questions:

• Has there been physical trauma to your TV? Has it been knocked over or struck by something? Was it working fine before that? If so you likely have a hardware issue. Since the physical trauma may have disturbed connections or the like, it's probably best to start at Connections and then skip to Hardware Issues. If there hasn't been any trauma, go to the next question.
• Are the lines uniformly distributed or just one or two? This will help with future steps. Go to the next question.
• Are the lines vertical or horizontal? Vertical lines, especially bands or bars over the whole screen, are more commonly associated with the T-Con board. Horizontal lines are more commonly associated with LCD panel issues. Keep this in mind as you go forward to the next question.
• Do the lines show up on all the inputs or only on some of them? If you're not sure, go to Connections, if they only show up on some inputs, go to Hardware Issues.

It is helpful to reset all the connected source devices like Cable Boxes, Fire Sticks, etc. This might cure the vertical or horizontal lines problem, and it is pretty simple to do. This allows you to keep eliminating easy-to-fix items so you can decide how far you want to go. If the reset cures the lines you're done. Otherwise, go to the next item.

The HDMI Cables can have problems that will mess up the video signal. There are two main points of failure, the input sockets, and the cables. Check the screen after each of these.

• First, disconnect and reconnect each HDMI cable at both the TV end and at the other connected device. Do this for every device that is connected to your TV.
• Use a known good cable and swap it with the cable from a particular source. See if that helps. Do this in turn for each source that you have. If this swap fixes a problem, then get a replacement cable and install it.
• Occasionally non-certified HDMI cables will cause problems in this way, it is best to use certified cables.
• Some newer models will have an HDMI test mode. you can check the cables for faults using this setting.

If your TV is not set to automatically update its software/firmware, it may cause erratic operation. Performing a manual update is another step you can take to eliminate a possible cause. Given the occasional instability of WIFI-based updates, if possible perform this using a hard-wired source, or if possible use a flash drive in a USB port on the TV. Samsung, LG, and Vizio support, for example, have additional details, especially for older TVs.

If you tried a software update and it had no effect, or wouldn't go, the last step before opening the TV is a factory reset. Given the frequent connection between line problems and the hardware of the TV, it may not be worth losing all the settings. You might want to go on to open the case. But, if your device is under warranty, you may want to try this reset first, and then get warranty service.

Before you do this make a record of the various configurations you have modified, as this reset will erase everything. Your TV will have all factory default settings and if this cures the lines problem, you will still have some work restoring your old settings. Perform the reset according to the instructions that came with your TV.

If that fails, you now have a choice.

• If your TV is under warranty: STOP HERE. Consult your manufacturer's support and arrange for a technician to visit or you can bring the device in.
• If Your TV is not under warranty, you can go ahead and see if you can fix the TV by checking its internal components.

Now we move into the area where the back comes off, so to speak. It isn't as complicated as it sounds, and you can check for a failure on the main board (the first thing below) without opening stuff up yet. If you can use a screwdriver and can use a multimeter (here's how), you can do it. Also grounding yourself so that you don't harm any of the boards in the TV with static electricity is valuable. Here's some info.

You can still use your eyes even if you can't or don't want to use a multimeter. Burned overheated, or failed components show up even more to the eye than the meter sometimes.

• You are mainly looking for signs of failure on the boards and you will replace the board as a unit.
• Remember that there are somewhat exposed high-voltage areas on the power supply board. If you have to do voltage measurements (not as likely for this type of problem):
  • Use common sense and where possible use one hand at a time for measurements.
  • Connect to the ground first, then with one hand check the high voltage connection. or measurement point.
  • Test leads with insulated clips on your multimeter will help greatly with this.

If you aren't comfortable doing internal checks, you can have a technician check it out. Just trying to repair instead of just throwing it out is a great way to go.

There is a chance that this is caused by an input port on the main board and one quick check is to see if the problem disappears if you shift inputs. This is the point at which the shift from closed case checks to opening the TV will take place if you discover a bad main board input and are willing to replace the board. Here are the steps:

• Plug the input that you have been viewing (with lines) into another input port
• If the problem disappears, reverse the process and see if it reappears, but use a known good cable to absolutely verify that it is either a bad port on the main board or a bad source.
• If the problem stays the same, try another source in the original port and see if the problem disappears. If it does the problem is in your source.
• If you get the same results for both sources, Lines in one port, but no lines from another, a replacement main board is in order, or if you don't mind a workaround, just don't use that input. You can decide if you want to do the replacement yourself. Not very hard generally.
• If the lines never changed, go on to the next step.

Here is where we must open the case to go forward. Dirt can both cause bad connections and also can cause problems with overheating. A good cleaning is helpful and will make the following steps easier. You will have an easier time seeing bad components, and any cables you disconnect will not get dirty.

• Make sure the TV is unplugged.
• Open the back panel. (This varies from unit to unit, some newer units don't even use screws and have to be popped open)
• You should also try to ground yourself and the unit when doing this as static charges can be built up by both brushing and compressed air (kind of unlikely).
• Give everything a good cleaning, with compressed air if possible.
• Go on to the next step. You might as well deal with the cables as well while the TV is open and clean. You don't want to get dirt into a connection when you check them, so now's the time.

Even before you test the various boards, just disconnecting each cable and reconnecting it can sometimes fix the problem. Especially important in this step are the ribbon cable or cables that run between a small board called the T-Con board, and the Main Board. Also, the cables between the T-Con board and the LCD panel are important as well. When a vertical line failure occurs only on half of the screen, the cables to the panel are an especially good item to check, as most T-Con boards have two feeds to the LCD panel.

• First, make sure the TV is unplugged.
• Disconnect and reconnect each cable one at a time.
• You might even want to clean the contacts on the ribbon cables with a pencil eraser before reinserting them.
• Take your time and be gentle. Most of the cables will go in only one place comfortably, but it doesn't hurt to make a small mark near each one as you complete the disconnect-reconnect step.
• After you do this, reassemble the back cover plug the set in, turn it on, and see if you now have a clean image. if so, you're done, if not go to the next step.

A very likely culprit in the case of vertical lines or bars and after cable cleaning. But if the lines don't show on at least half the screen, or are only in some irregular spots, then it is likely not the T-Con board as failures in this device usually show up over the whole screen area and tend to be widely distributed.

Horizontal lines are more likely a panel issue as mentioned before, but if you are at this spot, replacing the T-Con board is plausible, but you might try the items below, especially some workarounds.

These symptoms may also be caused by the main board on occasion (see below), but since the T-Con board is less expensive and if the symptoms point to it (just not with full certainty) it is a good candidate to replace at this point.

One unfortunate issue: manufacturers are increasingly combining the T-Con board with the main or motherboard. When your TV is made this way, you are in effect forced to replace both boards at once instead of just the T-Con. One sign of this arrangement is two ribbon cables running directly to connections on the panel, with no third board besides the Power Supply Board (the mains plug enters this board), and the Main Board (where all the inputs usually are).

If the T-Con board didn't fix it, this is the last stop before the panel.

Before replacing the main board (especially if the input port test above didn't reveal anything), you might want to mess with various workarounds on the panel. There are a number of connections at the edge of the panel (tab bonds and the like) that are subject to failure. These can be sometimes fixed by physical pressure.

For vertical lines, you will want to focus on pressure on the top and bottom of the TV at places that are aligned with the ends of the lines, especially if there are only a few lines or a cluster of them.

For horizontal lines, the focus should be on the left and right edges of the TV, aligned with the ends of the lines. Again, the same idea about the number of lines; just one or two lines points to a bond failure in the panel.

• You should try applying gentle pressure or even twisting the TV gently while watching the screen
• If you notice an improvement open the back panel, and see if you can apply tape to the edges of the screen so that a small amount of additional pressure occurs when the back is put on again. Sometimes just a slight additional pressure makes a contact work again and fixes the problem.
• If you don't see any changes, you can try replacing the main board.

This is the sort of repair that doesn't always have a clear path, you often end up "just trying things." What we have done so far has been to seek to clear away as many causes as possible.

If the panel is the cause it is usually not economically repairable except under warranty. There are other workarounds on the panel, especially for horizontal lines.

There is a workaround for greater numbers of lines that requires a bit of dexterity and patience but is rather amazing in its result. If you are ok with having a TV that is still functional and will in many cases be indistinguishable from perfect function but will not actually be working perfectly, then the workaround is likely for you.

The problem is likely a failure in one of the driver chips that are built into your panel. These are essentially unrepairable, but there is a way to bypass the defective chips so that other chips can do "double duty". Below are links to some workaround demonstrations.

A Link to a walkthrough of the process

A Link to an explanation of the process