Repair Hack Explained | How to Fix TV Horizontal Lines - Part 2

If your TV has

horizontal

lines

, do not throw it away. You may be able to get rid of those

lines

with a piece of masking tape. The problem here on the

horizontal

lines probably means it's an LCD problem and you can't really go in and replace it. a broken piece but I'm going to show you how you can use tape to divert the problem and get a good image again. My name is Rhys and this is the second

part

of a video series. If you saw the first

part

, you saw me disarm. a broken 55 inch 4k tv and I fixed it with a small piece of tape and in that video I mentioned that I was going to explain a little more about what the tape was actually doing and to do this I zoomed in very close to the inside of the LCD panel until the subpixel level to show you what's going on here.

This is going to be fun. I'll also use a similar technique on this TV with masking tape to get rid of these horizontal lines, so I hope you enjoy and learn something new today, let's get started. This is an LCD screen I took from a broken laptop. It's basically the same LCD panel you'll find on any TV. It is a small thin panel connected to a printed circuit board on top. helps manage the image. There's a lot of complex technology in this that makes it work and there are different manufacturers and different designs, but I want to cover some of the basics that apply to virtually all LCDs and how they work, whether they're an old laptop screen or a giant TV. 4k, so to understand the basic concept of how LCD screens work, you need to know that there are two key pieces of information that are passed to the panel: first is the image data that descends vertically and the second part of the information is the row indicating data that occurs horizontally.

Now sometimes people ask me, "Hey, help me." I have a line on my screen and I'll tell you if it's horizontal or vertical because that will give me a clue. It's an image? data problem or is it a signaling problem the data comes from these little chips on these yellow wires through these little wires that go to the bottom of the screen so the image data is sent to the screen one row at a time the time then row one is activated and then filled with image data. Row two activates, then fills with image data and goes to the bottom of the screen and then returns to the top to fill and update the rows of image data happen so fast that you don't even notice it, instead you see a moving image, but with a camera it looks like these dark lines are moving up.

I need to get closer to explain what you're seeing here when If you get really close, you can see the rows of red, green, and blue pixels or sometimes they're called subpixels. It is the combination of these three colors and their intensity levels that are mixed to produce the desired color pixel that you may or may not. I know that an LCD screen works based on the polarization of light, the liquid crystals are actually changing shape to polarize the light from 0 to 90 degrees to get the desired intensity, so when I say image data I mean the applied voltage to the liquid crystal. give it the desired shape and again it is more complicated than this but generally the image data is sent one row at a time within each subpixel there are three main parts there is a transistor which is the on and off switch there is the liquid crystal and there is a capacitor when you think of capacitor think of battery here are some photos of the very edge of the LCD screen which you may not be able to notice here but there are a lot of wires along the edge as we get closer you can see that these wires are going to each one of them. row, so the way this works is that the clock signals from the t-con board are used to tell all the transistors in a specific row to turn on one row at a time and when they are on they accept the data from image that are sent to them, it was very difficult for me to get a photo, but if you look closely here you can see the lines of data going down between each subpixel, the time needs to be synchronized so that when the specific row is in the data it will be send at the same time and while that row is on and the correct voltages are applied to the liquid crystals, those little capacitors also charge like a battery and each capacitor keeps those crystals folded in the correct shape long enough until the transistors turn on. again to receive the new picture data, so these darker bands picked up by the camera are the charge fading in the capacitors before that row is refreshed, so back to the original TV, the lines Vertical lines on this LCD screen probably mean there is a problem within the circuit. that handles the row signaling, so I don't really know what is causing the lines, but the isolation technique will help me determine which half of the screen has the problem.

This is the same diagnosis I used in the part 1 video to help me figure it out. The problem on that 4k tv on this one that drives only half the screen at a time, I find that the lines only appear on the left side so my goal now is to use tape on the ribbon cable to block some of the signals of row. going to the left side to detail the problem and hopefully see if the image can improve. I pulled out the t-con board to help me figure out where the queue marking lines are; otherwise I have no idea what lines to block in the video above I was looking for an abbreviation for the word clk clock since this is a different LCD design they won't be exactly the same abbreviations but on the right side I found what I'm searching, the stvp signal until ckb1.

The important row signs I can see where the lines I want are labeled on the right but the problem is on the left and there they are not labeled so I'm not sure which ones I need to block but I remember the rows. By turning one at a time, the same row of signaling is sent to both sides. This is how signal blocking can help deal with horizontal lines. The idea is to block the sign that has the problem and limp along with the signage on the other side, so I use my multimeter in continuity setting, it beeps when there is an electrical connection and here I can easily find the corresponding set of signs, since They are sent to both sides of the flat cable.

I've marked the seven signs I want to block and here I can cut the tape perfectly to match and cover these contact points and when I put this back on the TV I'll rely on the row signs on the right side to carry the load of doing to make the image look good on the screen, now I put the tape. In this flat cable we should eliminate the lines, but the TV is designed so that both sets of signals cross in each row, so we are only going to operate on one set. The image probably won't look perfect, but you might not notice. the difference and hopefully again the lines will disappear.

Now you might ask how you knew which lines to block on the t-con board. When I started I wasn't exactly sure, so I looked online to try to understand what the different lines are. The references mean that I even downloaded Samsung's patent application, this is from 2012 for the design of their LCD TV, I studied it and was able to decipher that these are the signs that drive the row that indicates that my degree is in computer engineering, so This sounds familiar to me. These signals are used to light each row in this design. The signals do not directly control the rows, so the problem on this TV is most likely a short or open circuit within the logic that controls the top third of the screen.

I don't get a good image blocking all the row signals on this ribbon cable. One thing I can do is use trial and error and unlock them in different combinations or one at a time until I get an image I like now. One thing I like to see is your questions and comments, so please post them below. I love helping people learn new things so I'd love to hear from you and also be sure to download my free pdf and join my email list to learn more.

repair

tips, tricks, tool reviews and more so let's try this and see how it goes to get everything back together inside the TV and here when it turns on all the lines are gone a little piece of tape removed all the lines and the image.

It looks great now the only downside is that if you get too close there are some very faint lines on the left side and colors that aren't black or white can look a little washed out, this is unavoidable because there is no signal coming from that side but When I sit at a normal distance, I tell you I don't even notice. In fact, I brought my kids to see if they could see something and they told me they couldn't tell, so for a small piece of tape you can rescue a TV that might otherwise be thrown away because it has horizontal lines on the screen.

Now, when you do this, you're not actually addressing the problem itself, but you are fixing it, and hopefully this solution will give you a TV that will work for many years. Come on, this video was the second part of a series, if you haven't seen the first part, go ahead and watch this here where I brought a newer 4k TV back to life with a piece of tape and if you don't subscribe to this channel, please. Subscribe to learn more interesting things like this.