LG, Light-emitting diode, Television set V LED test and replacement

I found on craigslist its not working the person. I bought it from said that the backlights arent working for whatever reason it looks like a completely black screen when you play it, but if you hold a flashlight up to it, you can see the picture faintly in the background, so hes thinking an led issue of Some sort i got it for 30 dollars and um i was. I was willing to take a chance for 30 bucks to see what i could do lets crack it open, not counting the feet. There were 20 screws uh, oh 21, theres one more here. I think i got the rest of them out im just going to do a double check. I like to put this these magnets here on my my driver. It helps it because my bits not magnetized helps me hold some screws on. There looks like itll just lift up and got some wires attached right here to the board and it is free. Okay, we do a physical inspection of the board. I dont see anything burnt anything loose on the led connector, which is, which is what this guy does. It powers up the leds, capacitors theyre, nice and flat. If you had a dome on them, youd have a blown capacitor, so not seeing anything here. I want to get my led, tester and well test out these led circuits all right, so my led tester. It automatically adjusts voltage up to 300 volts right now, its not connected to anything, so it just has uh 300 volts pushing out of it im gon na disconnect the led connectors here and i believe white is positive and red is negative.

So, im going to hook this up and see what my tester does. We are pulling about 100 volts dc im going to check the other circuit theres two led circuits in here and this time im going to go with red. Its positive black is negative. 300 still. So its not not pull anything im going to switch it make sure i dont have the polarity wrong still 300, so it looks like an open circuit uh. This means that we may have an led issue and were going to crack the case and take a look. So at this point found out, the leds were bad, some leds using the tester, i decided to start dismantling and i took off the feet: the wi fi adapter, i unscrewed the screws that hold on the um. I think this is the screen processor plate here and a bunch of small screws that hold the outer bezel and then im going to try to see. If i could crack it open could be a personal call on on whether or not to even continue because its a pretty big job getting this all opened up and replacing other parts. But if i had found out that i was getting good voltage, pull from both led circuits id, probably start replacing the power board. The boards are pretty cheap, nothings really expensive on this tv to replace, but the leds itself has a lot of labor. So im just gon na get into it and see what i can find.

Okay, i got the bezel pulled off and i found that the screen comes up really easily everywhere, except for here. Its attached to the plastic trim that the bezel clips onto, but i was able to get it up on on these tabs here all the way across. So the whole thing is disconnected im going to peel off the screen and set it to the side. All right with the screen off this is what we have some sort of uh plastic material, and i believe these uh, the rest of this trim has to come off be sure to mark where it goes. There are some points right here, i believe, to use a screwdriver on so im going to grab that trim off all the way around. Just by using the screwdriver and undoing the clips now theres, a piece of plastic and some paper down below it and the leds. You can see the lens cover right here, so im gon na negotiate this plastic and paper off real quick got all the covers off. Leds are completely exposed. Im gon na show you the polarity here. If you look in this area, you could see the positive and the negative. These contact points are checked for checking individual leds. The same polarity is used on this side, so this will be negative. This will be positive and you can check the whole strip all at once, so im going to go through and check. Some of these i tested the led strips, and what i found is one of my leds is bad, causing the tv not to put any voltage through because it could sense the air thats.

Why none of mine light up when, when the tv is on but ill show you how to check a strip? You line up your polarity according to the the markings here, i could check a whole strip by touching these two contacts that strips good the strip up. Above do the same thing: it lights up this strip on the bottom, this one doesnt light up, so i could tell theres something wrong with this strip. I could go to the individual contacts check that led is working when i get to this one. It doesnt light up and were not getting any voltage, draw some sort of open something wrong with that led. You could change the led if youd like theres ways to do that special solder tools or techniques theres a lot of labor getting into the back of this tv, and i figured id rather be safe and for 37 dollars. I just bought replacement leds to to take care of all of them at one time, so hopefully i dont have to do this again anytime soon there are four screws on each strip and it looks like several of them just have to be loosened a little bit And it should slide off this screw on. The very end needs to be removed completely and then theyll slide out of the keyhole, like that, the strips are different sizes. The one i just removed is the longer of the two it tells you which way voltage is going out slide that in place.

I replaced all the led strips and, if you remember early on in the video i tested the leds before, i could actually see them using this plug here. The white one is positive and the red one is negative. This particular strip is pulling 98 volts dc. I could see some lights come on see if i can move it here at the bottom, so they went out, they came back on. You can see through this these little holes so that ones working and oddly enough, the other side black is positive. Red is negative. Were pulling a hundred 103 104 and i can see lights come on through the hole here by my finger. If i disconnect it, it goes off and the reason theyre different voltages is because half the strips had more leds than the other. But now we have some voltage being drawn before one of the sets wasnt drawing any voltage, because the open im going to go ahead and put the tv back together. All right, i got got ta put back together enough to run a test im gon na plug it in and see how it goes. Theres our picture 67 55 inch 4k, not too bad. Well, thanks for watching, i got more.

What do you think?

Written by freotech


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