Trashpicked Samsung LCD TV Repair?

Hello everyone, welcome back to Adrienne's digital basement. What you see here on my coffee table is a 32-inch Samsung 1080p TV that they picked up from the trash and now I don't know why they threw it away, but chances are it doesn't work now. here in my cart I have an identical TV which means I have the actual remote control for the TV which might help troubleshoot but let's see if we can get this to work and if there is a fault maybe I can fix it so Let's go deeper. and take a closer look from a visual standpoint, the monitor is a little dirty but otherwise appears to be in good condition now that I have the power cable connected and the red LED is on here which is the normal behavior when this is turned off.

I don't think there are any cracks on the LCD, although it can be very difficult to notice on these dark screens, there are definitely some scuffs and scratches around the bezel; Otherwise it looks decent, there is not much to report on the back of the monitor, one curious thing is that This space here is normally where the model number and serial number label goes. Someone removed it. This monitor doesn't really have many inputs. We have a single composite/component input. Here there is a 3.5 millimeter audio output and an optical digital one. output antenna which is for ATSC which is also analog here, there is a regular power input here on the side, there is a USB port which I think is just for 5 volt output.

I can't remember if this thing supports USB sticks and has two individual HDMI inputs in typical Samsung style, there's a little joystick button here that's for control when you don't have the remote. Now this is the television. This is the other TV I already had that has the sticker. Now that the sticker is completely missing on the other TV, I have no idea if it's the exact same model, but it certainly seems fine. I apologize for all the glare, but we're here in the living room, which is where I had the remote, so I'll probably go down to the bench to do a little more testing, so it's plugged in, they have red LEDs on. , let's press the power button, there is a normal Samsung startup beep that you can turn off, luckily I have that.

Off on the other TV I hate that sound and what happens is the power LED blinks for a second, it can be hard to see, well the power capacity LED stops blinking and we definitely don't see anything on the screen. It sounds normal with the startup sound which would imply that the main controller is working so what I'm going to do is take this flashlight here and I'm going to shine it towards the screen and see if the problem is just the backlight that's the one. problem and maybe we can see if we have a picture or not, well from the beginning I can see something on the screen, let's zoom in with the camera, then you will see that it says weak signal or no signal and it looks like it's just static, you know, like if it was an analog input so let me use the remote to try to navigate the menus a bit but there is a bright side which means the taillights don't work and I'm pretty sure this is an LED Backlight so which means it's not likely to burn out, so possibly it's just a power supply issue.

I was able to navigate through the menu and opened the image test and you will see here that it shows color bars and it definitely looks like the The entire image is displayed correctly. I don't see any cracks or any kind of problem. Everything looks totally fine. I was able to navigate to the backlight menu and it is not off. It's not like you can change the backlight to any type of setting. turned off anyway, but I would say the problem is purely with the backlight on this TV, it has nothing to do with the software settings, and I was able to connect a small antenna to this and it automatically tune to a bunch of local channels, so it's definitely working and there's audio and it's picking up high definition feeds of some commercials right now so I think the next thing is to take it down, take off the back cover and let's take a look at what exactly we have at the moment fair.

That's fine in the bank. I actually don't know how to remove the back covers from LCD TVs. I've never done it, but I assume you have to remove all the screws. I just don't know if I need to remove them. I removed the stand, so that's why I'm going to use a towel here and place the monitor face down on the table and then remove all these screws so it looks like it's under the stand. There are four more screws holding the back. Look, you definitely need to remove the base. Yeah, I think on the joystick there's a little access panel here that we took off with a screw and I think it goes to the joystick.

There's a little black wire here. cable let's take that out and there might be clips too there we go so we're in and it's a pretty simple thing here here's the main controller for the TV the joystick plugged into this port right here this thing that looks like a cable for a floppy drive on an old PC that definitely goes to these speaker modules here and here this controller makes the LCD output that goes to this board. I think this is called a t-con which is what controls the LCD screen directly and these two ribbon cables here power the LCD panel that displays the image and as we saw when we looked at it with a flashlight we didn't see any problems with the image so I don't need to mess with that stuff here this is the High voltage power supply converts 120 volts AC to the voltages that the controller needs and here this wire at the top is definitely the one like this while the light The backlight is connected directly to the power supply and this here is probably the backlights power supply that generates the voltages to drive the LED backlight.

There is a signal coming from the main controller that allows the backlight to basically turn it on and off and also controls how bright it is, so possibly there is a fault here that it is not telling it to turn on. on the backlight, but I think the problem is most likely the power board or it is possible. I assume the backlight has failed, although looking at these cables there are two gray and two black cables, which makes me feel there may be two separate sets of backlights. here like maybe there is a strip that goes half the width and another that goes the other half, so if one of them were to fail, half the image would be dark and not both.

I think I'm going to plug this in and start by just physically wrapping it around to see if that makes the backlight come on, so I went to turn on the TV and found out there was actually no way to do it because I was pointing the remote at it to try turn it on and nothing. Well, this is the little joystick module that was on the back cover that I disconnected and if you notice here is the infrared receiver, so I have to plug it in before I can do anything. Okay, plug this in here, press the button.

The control board has three blue LEDs, which is interesting, so we definitely don't have a backlight here and it's a little difficult, a little painful, I like to lift this up to look down. I can see that it actually dripped some water into the box. there are some drip marks here I'm going to use my plastic screwdriver here definitely nothing happens when I wrap the power supply I think the next thing I'm going to do is just check the voltages of this backlight cable here to see if there's even power. As I leave here I have to thank Samsung, look at this, they have labeled here which pin comes out of the power connector on the power supply, but up here they have actually listed exactly what the voltages are, in fact the LED driver output. it is at 91 volts at 450 milliamps, the rest of these are available in them, so for example your ac says it is 13 volts, that 13 volts is 12.8 and 1.5 amps, etc. etc. .

Up here, this is the backlight LED control and you can see there D. plus s - s + D - so I guess that's the way it's connected even more interesting this power supply is a multi-voltage power supply and I could have sworn that on the back of the monitor where it shows the input it only says 120 volts it doesn't say it can actually run multi voltage here on the main controller board there is a connector here that says debug and I wonder if it's a line serial maybe worth connecting. I'm like jumping but I was about to analyze the output of the PWM signal and also the LED driver with the oscilloscope and I think it's going to cut the power supply.

Let's just take a look at the back and see if we have any broken solder joints on the CD. TVs are made cheaply right now, so they are extremely modular and very easy to assemble and disassemble, so the through-hole components will be the ones that have problems, so I'll only focus on those specifically. I've been poking around this power supply and something interesting is the output connector for the LED driver. You may see it labeled as D plus s minus s plus D minus. Well, the reality is that the middle three pins are all connected to each other.

You can see the thick traces. Here the one on the left is labeled D Plus which is actually the positive voltage of the driver and this one here is the negative and the two in the middle are connected together so when you connect this LED cable here it appears to be connecting two LED strings. in series, but I'm measuring 146 volts on the D plus pin here and it looks like these power supplies, the LED driver section definitely has an open voltage when nothing is connected, that's higher now when I measure D plus if something is Plugged in or not, it is the same voltage of 146 volts or so that leads me to believe there is something wrong with the LED drivers here.

I think what I'm going to do is just take this whole TV apart. Let's remove the back cover to expose the LED drivers and see if. we can see a fault, maybe there's a bad connection there, maybe they're just totally wrong. I don't know so now I have to try to figure out how to take this apart obviously the first thing I have to do is disconnect the ribbon cables from the t-con so you just lift up these little flaps and gently slide them out so they disconnect and it looks like there are only plastic clips to hold this metal cover on, so I'm just going to pry these up. away little by little and so on and then I think this whole back cover comes off and that will expose the LED modules and I have removed the tape because this wire probably goes through this hole.

I would assume this piece of tape probably feeds in. I go back there and then I can remove this whole back cover, oh that was a little annoying, okay, so what you see here is the actual LCD panel, it's under this kind of light diffuser , these are the different layers and everything moved so I have to say the way they are put together it's just plastic so everything moved there so I'll have to try to put this back together if I'm going to try to get it. TV back together, this is the backlight, it still has the electronics mounted, but if I lift this up like this, there are the two LED arrays and they are definitely connected, pretty sure how they are connected to each other, yeah, I see.

Okay, so they're in series, but instead of being internally connected to each other, they each have two wires going back to that connector and then that connector is connected in series on the power supply. Now I have read it as one of the problems. With these all the LEDs are connected in series and if one of them goes out the entire backlight fails and on some of the larger TVs I guess I think they are visually connected individually so you may have sections of the screen to turn off, but unfortunately with this particular TV it is small.

I think if one LED fails, everything opens and we have no more backlight, so this TV is connected, everything is on at the moment. I'm just missing the LCD panel so we can see the backlights. which are not working currently, we have the multimeter and I'm going to check the voltage, so remember it goes on a strip, one strip and out, they are all connected in series, each LED here there are 12 per strip, so go down one then into the next one and then back there so when I measure the voltage there are little pins here so there is a positive pin which is 153 volts and then there is the negative pin which should be the 141 volt output and that loops backward.

The power supply comes back to this probably at the turn of our 41, so it's the same as the pin there and then the pin that should be the ground. We are getting one volt on this strip, it seems to be going all the time. down and back or getting voltage and then on this we don't see the output now there are these little spots over the LED emitters that prevent us from measuring and checking each LED but the traces are available here in fact there is a little pad of test right there and there's a test pad right there so there are occasional test pads so maybe I can power parts of this with the power supplypower my bank, three LEDs.

I'm going to unplug the power to the TV, that's it and probably Unplug these connectors here so I don't send any cents of power to the power supply, so I have these two test leads connected to my bench power supply, except for a few nine volts 9.2 actually, but only about 20 milliamps and no test points. I've found on these strips, but these are sharp test leads and I just scrape off the solder mask and I definitely found problems with this particular strip, so here's an example if I plug in here and we see here one, two, three here, like this that we turn on.

Turn those three LEDs on without problems and I can know that with less volts I can make each one work and the same thing if we go from here, so it's one, two, three, we have three LEDs on, no problem. Now I've flagged a couple of these like this is a problem, this is a problem and there's one over here that's a problem, this one I think is shorted, it's dead and it seems to have died and stay connected in series, if I try to connect it Well, nothing happens, at least the current passes through it, so the others would light up, but if I go here. which should illuminate this one this one we don't get anything this one is dead and now it's open in this part of the board this one here is also dead so we go there and under the tape here I connect to the positive there we go so we have another one that is dead and it goes through it and the strange thing is that if I connect directly to it, it flashes for a second and then it cuts out and you know, that killed it, so it's totally dead, now let's see.

If it's still not good, that died, it died open, so it was kind of a step, but it was just flashing and then dying so that one is open, this one is dead, but passing current, this one was dead and then it fell short, I guess which is like this. I kind of blew those out on the top strip, but it's not right on this one either, so these two LEDs are bad. This one here when you turn it on, when you give it power, it runs for a second and then turns off, but it seems to pass current.

This one too Exact same problem so they both died this one here works fine and that one works fine then this one here is also unstable its strange as sometimes it works but most of the time it just flashes on and that one looks dead. short according to the power supply, this is not at all short, he is drawing 42 milliamps right now, this 42 milliamps, yes, that is actually the current maximum. I have allowed these to consume 42 minutes, so they are not working, but everything else is on. this strip is fine, all the other LEDs here work, just these three are defective and on this bottom strip, this one is defective, this one is defective, notes here, I have removed some of the small lenses, I removed one here right now the way that What I did was I used this little photo here and I took it off like it came off.

I assume they are melted or stuck together. This LED has a small black mark in the middle so you can see it. it has a little black mark on it so I think this was one that was dead and open this one here and it doesn't have that much of a mark let's take this one out this was another bad one it has a little bad mark there also up here these are the three on the strip top that flash and then pass current one doesn't have black mark the other one doesn't have black mark now and it doesn't have black mark so I removed the LED strips and yeah with aluminum backing I mean it's going to be a little bit hard to solder, these are essentially giant heatsinks, but six bad LEDs and I guess what was happening is that they had failed and the TV was just driving them anyway and probably what ended up happening is the voltage goes up I think that when some of the LEDs don't close that means they are still passing current and eventually one of the others just gave up and didn't open and that turned off the entire backlight and that's when the person threw this TV, so okay, the question at this point is should I fix this or not?

Hello. I did a quick little test to try to remove one of these LEDs and had no success. I'm guessing you need a lot of heat or maybe you have to heat this entire strip first. Doesn't it remove all the heat? I looked online and it looks like replacement strips cost 20 bucks, not that bad, but I guess the question is is this TV worth fixing? It seemed to work, of course, I took it apart. I may not have broken the panel in the removal process, but anything is possible, so at this point it's really a decision what I should do.

Should I order the replacement parts for this or should I just separate them? These parts are interchangeable. with the TV I have upstairs, so if I keep these components and throw the rest of the TV in the e-waste, at least I have spare parts for the TV upstairs if it ever breaks, but yeah, let me know in the comments section if you think I should go ahead and order these parts and try to fix this so I soldered some wires to the debug port here is my serial it's 3.3 volts so of these three wires here the gray wires are ground and then these They are Rx and TX.

I connected this one but I don't need it. It has five volts and is not really used. The reason I didn't put a pin header on it is it has a different pin pitch than what I have stock so unfortunately I just put wires directly into it. Nothing interesting happens when you turn on the TV it just shows this so that's it and if you change the channel I'm pushing the channel up or down and if I turn it off it goes into standby mode. Interesting when it's off. You can do it. Press the buttons and you end up fine, so that's it for this video.

Sorry, I didn't actually get the TV to work. I really had no idea what was wrong when I started, so if you thought this was interesting in any way, you know, I appreciate it. A thumbs up, but you might not like these videos because they're a little different from what I normally do, so feel free to give a thumbs down if that's the case. Leave your comments and questions below and don't forget to let me know if you think I should try to fix this or just throw it away after all? Okay, see you next time, bye.