Testing TV Backlight LEDs

Video demonstrating how you can test your backlight LEDs without expensive test equipment.
Summarized versions of most projects: www.swappart.com
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[@leecewest]

I picked up a 50" LG with a bad back-light. I used a 2032 with a 3D printed holder with this needle method and found 4 defective LEDs. I bought 12 LEDs for $10 and replaced the 4 bad LEDs and the TV is working! Thank you very much for this video!

[@metrork1]

You got ripped off at that price. Check out eBay

[@SaccoBelmonte]

Thank you that was pretty effective! I could pinpoint the exact faulty LED with this. I used two rechangeable batteries for a total of 2.66V and two needles , which totally worked.

[@wecansavenergy]

Thank you very much for your explanation of testing these LED strips. Very helpful!

[@simonpreece6916]

Cheers worked great for me - found the LEDs which have gone. My bars are Vestel revo.2 (i think) with 9 LEDs a piece, working from the end which plugs in i tested by placing the positive probe into the large area before each LED and the negative on the large area before the next LED (note the area immediately after the LED being tested just shorts the battery so skip it) to test the led at the tip I found it easist to put the positive probe in tbe same as before but put the negative on the main negative solder tab for the whole strip. I hope the above makes sense - it took me a while to work out where to stab them and i was about to give up! Good luck all Now i just need to figure out how to replace these bad boys

[@rarelectronicstv]

Nice tuturial sir..i watching from the philippines...thanks

[@perryedwards3045]

I used your tip about the 9volt batteries and it worked perfect! Thanks, you saved my 55 inch Hitachi from the garbage.

[@abdulmajidmahvy2909]

I JUST MADE TESTER WITH 12 0 12 TRANSFORMER 500 MA. I GOT 32 V.WITH BRIDGE RECITATION AND JUST ADDED 1WATT 1K RESISTOR AT +SIDE FOR CURRENT LIMITING AND WORKING WELL!

[@coldblackice]

Great idea!

[@douglilley3795]

Ya can Just use the Diode Function on the meter as it outputs a low dc output :)

[@Legend-sl9bn]

How do i do this i only got a cheap multimeter

[@linzmcgeorge]

Wealth of knowledge! Thank you! May I suggest a set of flat diamond files to sharpen your probe needles? They almost last forever and have a ton of uses.

[@TronSAHeroXYZ]

You helped me fix my tv TY so much man. You're really appreciated.

[@saarike]

Excellent! Thank you.

[@HaLo2FrEeEk]

I recently (today) took apart a very broken Samsung TV. Can't remember the model number, but it was a bare bones TV. I'm pretty sure it was for commercial use (like in a store or something) because it only had the most basic connections (1x each composite, component, stereo audio, 2x HDMI). Anywho, The screen was completely shattered, but the electronics were in good shape, and the power board was very clearly marked with the pinout of each connection. The LED backlights look exactly like the ones in this video, and there are 4 strips of 8 LEDs each (32 LEDs total), all in series (each LED is in series on each strip and each strip is in series on a "bus board"), but the pinout for the backlight connector indicated 118 volts. Now the connector has 6 pins, but only 4 wires are used and of those, only 2 are actually connected to this bus board (I can see the traces if I hold it up to the light). Given that the circuit board indicated 118 volts, with 32 LEDs, that indicates just under 3.7v for each LED, not the 3.2 that you specified in this video. I tested single LEDs with 3.3v from a computer power supply and it worked fine, and I also tested an entire strip of 8 with 24v (by using a computer power supply's -12v as ground and +12v as positive, so you get a 24 volt difference). Needless to say, this only provides (at maximum) 3v to each LED, and under normal circumstances (my -12v rail wasn't actually -12v, so my actuall voltage difference was only around 20.5v) around 2.5v each. They lit, but pretty dimly. I then went on to power 6 of the LEDs with this 20.5 volts (meaning 3.4v each) and they looked great and handled perfectly. Anywho, thanks for the video. I'm gonna look for a way to modify the strips and/or bus board to either have all the LEDs in parallel, or each of the strips in parallel. I recovered the white acrylic diffusion panel, so I'm gonna make a nice-looking light box for the shop :)

[@irishhandyman2009]

I did the same thing with a year old Vizio 55''. Cant remember the model. The screen was cracked. After removing everything and got down to the LED's I saw that the strips were only held in with 2 way tape. After saving the wire leads to the strips I removed each one. They were paired together with one end having the wire leads, and one end plugged into the end of the other strip. TO make a long story short, I built under cabinet lighting, even mounted under the toe kick. Works great. The trick is finding a good power supply. I found that replacement laptop power supplies were perfect. The right voltage and right amperage. Mine worked with 19 volt, 3.42 amp. Found them on Ebay for $7.00 to the door. Considering the price of the TV and only using it just over a year, I figured it owed me something. Hope this helps someone.

[@coldblackice]

@@irishhandyman2009 Awesome idea!

[@thenegotiator9701]

Use maybe the multimeter? There is a function for that

[@193mirza]

nice video

[@winstonclarke9221]

Nicely Done👍.

[@noelsaludares4652]

TY so much i have learn how to test led. Thanks a lot

[@adrianfgaleano]

Thank you! I'll try that. I have those led panels from a a broken sony bravia and couldnt make them work by applying voltage at the beginning. I search almost the whole wide web trying to learn the Voltage

[@SwapPartLLC]

+Adrian Galeano You have to have the correct polarity too. If you don't have enough voltage, you will not get them to light. They are usually 3.2 volts per LEd, so if you have a strip of 10, you would need 32 volts to make them reach full brightness, but they would light with probably anything above 25 volts.

[@adrianfgaleano]

+swappart.com Thanks! The tv was a KDL-48R475B with 6 leds per strip, 12 strips.

[@adrianfgaleano]

+swappart.com I've made them work! I have try with 12 volts, never ocurred to me that they where in series or to scratch the paint. Kudos to you.

[@SwapPartLLC]

If you have some long thin needle probes, you can test with a multimeter on diode test mode. The thin probes can slip right under the lens. You won't get full brightness, but you don't need to. Just seeing any light at all is an indication that it is a good LED.

[@markfothebeast]

The aluminum bar is a thermal circuit board. My Vizio 32" LED has 10 lights and draws roughly 29-30v = 2.9 - 3.0v. Repurposing the lights.

[@jay22alco]

when to use this? I lost my mutlimeter and I don't have a tester for backlit. hey, I have a 4.2v battery and it worked. I also try lighting individual led for a split second enough to determine if their working. sometimes it will light but very dim indicating the led is also bad. make sure to use a shades, it hurt my eyes after checking through all them and the last one I checked is the bad one.

[@kevinhancock4064]

That's cool and it's safety solder onto a battery ? Be cheaper than a tester could you hottest the whole strip ? Say if it were 6 leds 6x 3.2 volts? Just curious great video thanks I just ordered an inverter as it were cheap if that don't solbethe issue i will be testing the l.e.d's

[@royboy6180]

Was Wondering, what Burns out this leds if multipple are dead? whats stoppin them from burning out right away? Also Does Wrinkles in The White Paper that covers the leds affect the picture when put back together? Thanks

[@jesussaves6671]

this is cool. can we do it without removing them from the panel

[@mickeygovender]

Thank You.Your video has really helped me.

[@timunksatriabatam9574]

Very good. Thank you dear

[@marciajohnson5844]

@SwapPart what is the voltage that I would use on a multimeter to check the LED strips for a TV cuz I'm having a hard time trying to figure that part out and I would like to know what exact voltage am I supposed to use I have an element 50-inch TV

[@johntorres5442]

What happen if you remove the button like glass does it still work as an led?

[@jenko701]

I had a 10 led section and used 3 , 9 volt batteries in series and it worked great , I did not have to stick in the needles through to the foil and could test 10 at a time. It was easy to find the the bad row then I went one by one.

[@SwapPartLLC]

+Jjames Anderson I have done this several times since you suggested it and it is definitely faster.

[@-COBRA]

3pcs of 9V batteries?

[@thesinwagin]

That works when the strip lights up. Depending on the type of fault of the led, the entire strip will not light. So you test have to test individually to find the bad one(s)

[@ampuansiregar1845]

Jjames Anderson vbu

[@kevinhancock4064]

@@thesinwagin I'm curious why is this ? Wouldn't they all test the same way ?

[@petertaylor3424]

awesome mate . works a treat 👍

[@brownjumbotv7256]

What is the voltage range per lamp or led in a strip?

[@irishguy200007]

Great video but I still haven't a clue where to place tge probes, It's very confusing

[@neilc7259]

A lot simpler method is to scratch the side of the LED strip with a razor blade just enough to expose the copper. Then use your DMM in diode test mode.

[@liamwatt4840]

You mean the sides of the strip to the left, center or right with positive and negative, as he showed in the video?

[@royboy6180]

Hello There, What Causes these Strips or Single Diodes to burn out? Especially in So Short of Time, Like a year or 2 Usually? Also if i replace the strips is it Likely They will they burn out again in the same amount of time has the 1st time? I Also would like to fix the Issue that is causes the (Strips or Single Diodes) to burn out in the first place, So I Dont Have To Replace So Often. Really Would Appreciate Any Tips or Ideas u Guys Could Share! Working on a -----> TCL 65S401TKAA 65" 4K Ultra HD Roku Smart LED HDTV Thanks Alot in Advance For Your Time!!!

[@suyvik]

I’ve tested power source with a reading of more than 100v, it’s this correct or do I made a mistake?

[@ImranAli-rp4kd]

Vik San depends how you tested it , 1 whole strip will never be over 100v on backlit TVs but if you got lots of strips and there’s just 2 wires going to power supply or backlight inverter then it’s possible for it to be over 100v

[@nelsonwalker4370]

have a e47oi-a0 did the voltage test had 129 volts on both vout 1&2. video says it's the LEDs. I'm getting ready to test the LEDs. what I don't understand is why they all are out. is this a possible problem with it interface board, or are they wired like Christmas lights if one goes out they all go out.

[@santoshkumarjha1979]

From where can I get backlight strips for sony bravia tv

[@peshmadscientist1833]

should always use a dropping resistor when testing LEDs. they ARE diodes, so for 2cells, {3v} maybe just 10 ohms.

[@cpcnw]

Yep, learnt the hard way. Two Duracell at 3v left it on a bit too long and there was a strange smell. Then I noticed the led was dim :(

[@GrantsPassTVRepair]

Some LEDs use more than 3.2 volts, and some of them integrate 3 LEDs in one so they use 3 times the current.

[@thenegotiator9701]

Grants Pass TV Repair or 3in series so hijger voltage

[@MrDriftwood77]

Is this a side backlight or a behind the panel backlight?

[@xcross8537]

MrDriftwood77 yes, it’s very risky procedure especially if it’s not your TV.

[@jasongoestohell123]

thanks

[@MANISHH]

unable to find those 2 points for needles... what to do??

[@josephsepe9186]

what if u see leds work ? what is issue then

[@patrickduffy4583]

I have a vizio e470i I had no picture had sound when tv went out, change the power board had 68 volts at leds1+ and 2+. Still no lights,tested r/s leds, light up, tested r/s and l/s strip together l get nothing. l tested each light one at a time 4 are out, whats got me is why when I test the two strips together, I used two 9-volt batteries wired together. Any leads for me?

[@TruckingWithJimbo]

ever got anything I have the same problem

[@davidb2438]

Buy new LED strips and replace. The LEDs are in series, if they are shorted, the rest of the strip lights, if LEDs are open, the strip will not work

[@Pyro17059]

Can you replace a single led on these kinds of strips?

[@Marcoosianism]

Yes, check out v=U7hnmJS8Gfg

[@coldblackice]

@@Marcoosianism Thanks!

[@alejandroconstantino5747]

@@Marcoosianism no

[@ThePHILALLENSHOW]

you must have the magic touch tried it did not work for me

[@dontounsley813]

I soldered the two batteries together and stabbed all over my both sides of the l.e.d. and switched polarities and still never got anything to light. even tried it on a new strip and nothing. my strips looked different from yours by it didnt seem to have pads like yours. I think mine has three columns running down the strip. But the l.e.ds looked the same as yours. Any suggestions for me?

[@Measuray]

+Don Tounsley - Do you have the battery together in opposite direction? Try touching the pad where the line is visible. Think of the line as a separation and then touch the other one opposite to it.

[@dontounsley813]

+Measuray Frank yes batteries in opposite direction. Second time I put this together. First time I checked it with a multimeter and also came up with 2.9 volts. But on my backlight strip (from an Element 50 inch) it has a positive and negative connector and going from left to right is a line from the positive and negative making three paths(?) across the strip. And in the middle path is where the l.e.d.s are soldered. I dont see any up and down lines in those paths to separate into pads though.even still I have put probes on either side of the l.e.d.s as well as on opposite sides using all combinations of two of three as being neg or pos. If that makes any sense?

[@dontounsley813]

+Measuray Frank it would be easier if I could show you a picture. Is there a way to send a pic in my reply?

[@josearmandogomezsantos7760]

if i have a battery of 5 volts and the led is of 3 volts the led will burn

[@SwapPartLLC]

if you don't limit the current, then yes.

[@petervanmaren6464]

Why don't he use his Multi meter he has

[@coolissimo69]

You could have done a drawing so would be easier to see it.

[@foridkhan8490]

led

[@samj1012]

where did u learn how 2 make tutorials ? MIT ?

[@SwapPartLLC]

Well, it wasn't the place you learned to read and write.

[@coldblackice]

@@SwapPartLLC M-M-M-Mic-DROP. 10/10, nicely done.

[@cherifmellah9664]

mellah cherif

[@user-jl2zl9if3t]

bu deyismeyin isulu basga cürdü

[@bobyla13]

ooooooof....a lot of bla bla bla!!!!!

[@wolfgangboettcher3126]

Was macht der da? Quatsch