Great video. I appreciate you taking the time to post this. A huge time saver knowing how to test the strips without tearing down the entire assembly! Thanks 12voltvids!!
I find what you did was not only easier and a time-saver, but economical and practical as far as the customer was concerned. A quick and inexpensive repair - another one working.
RoughJustice 2k18 Right and what those that don't understand how these power supplies work, will not shorten the life. If another led fails then it was already on its way out. Running the lights at 15 or under will ensure no further stress to any of the remaining leds.
Another great video. I like how you challenge these other techs when they start talking crap. Most of them can not back up there statements but you certainly can. Your hard work is greatly appreciated..
Dispite what some people are saying about your repair methods, you're doing what the client requests. I'll be attempting this repair on a Samsung TV soon, (my intial diagnosis was a faulty T-con board, this video has set me on the right path). Great video
That's because those critics have no idea what they are talking about. When I hear them say things like you should have replaced the diode as now the rest are going to be stresses just proves they know nothing about how the current limited power supplies work. An led will drop its junction voltage no matter what. It is the current you are controlling not the voltage. The led strong runs at around 150 to 250 volts depending on how many LEDs are in the string. The power supply doesnt care. It is running on the current drop and it will maintain current bo matter what. The biggest killer of leds is turning up the backlight to full. Running on full will produce more heat and if there is a weak diode it will pop. Turning the backlight down to 75% max will ensure that none of them are stressed to the point of an early failure. 1 or 2 jumpers diodes will make absolutely no difference at all. I have been running one at home I fixed 2 years ago and the only way you can tell is if I put up an all white screen then you can see a slightly darker area. Some people make accurate comments but most are just repeating someone else's uneducated opinion. On this set it was fix it as customer requested or scrap the set. This one is still working fine.
12voltvids I've read through all of the comments, I did notice a lot of people saying the same thing. Your video has given me the confidence to make the repairs to my tv. Again great video and it will be my "go to" reference video to make my repairs, will save me some money. I did check the backlight setting on my LG led/lcd tv, it was on 70%, changed the setting to 60%, the tv is seven years old and still going strong.
Great video! I had my own TV shop from 1976-84 in Michigan, but never worked on the LED/LCD TVs before. Another problem with over driving the LEDs is permanent screen burn from stationary images. I know, because I created that problem on my 65 inch Samsung LED TV. Using the "dynamic mode" constantly caused large dark areas on the display. Thanks again for sharing this video.
LCD TVs suffer image retention, but it is not caused by the backlight level. It is pixels that stay in one state for a long time tend to stick, and this can me permanent. LED tv is still an LCD panel, just the light source is LED as opposed to fluorecent. OLED and Plasma on the other hand, and CRT for that matter will get permanent screen burn. Look at my latest lorex camera video from yesterday and I show a shot from my old CRT camera monitor all burned to crap. Even when it is off you can see the image.
Just picked up a Samsung tv with the same problem. This video has definitely helped and no doubt ill be able to fix it now. Seems like a common fault. 👍👍
Good fix. Last time I had to fix one of these Samsung TVs, I had quite a hard time. There was no datasheet for the LED backlight driver IC, and I couldn't find schematics anywhere. Turned out to be the red glue under a SMD resistor. It became somewhat conductive and was throwing off a transistor bias, causing the PWM coming from the main board not to reach the driver IC. Without that signal, the LEDs stay off.
Extremely informative video, all steps and proper procedures were documented with clear instruction, thankful to have come across this video, just picked up a 55 LED Samsung with a backlight issue, hoping to put my soldering skills to the test! Thanks!
@@dannybfmv Hey Danny! So I had ordered the individual LEDs to solder on, did a few strips and such, but it still wouldn't display properly, made me question if buying the strips would of fixed it! I eventually called it after about a days work on the TV, there were far too many burnt out to do them individually
OUTSTANDING! One the most professional, step-by-step, yet succinct repair videos I`ve watched. I repair a tremendous amount of electronic and mechanical devices and found this one particularly helpful. Thank you kindly sir!
All things considered, this is an appropriate repair for this situation(waitng time, cost,etc) and it seems that no matter how often you say it, some people just don't get it! Dave, you have a lot of patience giving the same answers over and over, that would drive me bonkers.
You're right about not using the backlight for 100% full brightness! I use my Samsung Led TV with 10 out of 20 backlight brightness. And even with that setting it is stillbright enough! I even think all of my settings are just set in the middle. After 8 years, the TV is still going strong!! Indeed a good tip everybody!! Sorry for my bad English...
Refreshing to see you keep the heat on for a good few seconds when soldering. Just picked up a 46in Smart Samsung and have found 2 failed leds in the same string. Now its time to visit the TV shop and see if they will give me a few strings from a S/H parts box. I can just hear them now... Sure, that's $50.00 thanks. lol.
Ohhhhh buddy. I'ma about to make a lot of money. I have found about 7 TVs just this month. 5 worked and 2 were smart TVs with the backlight not functioning. Sold the 5 other tvs for cheap because they weren't smart TVs. 1 70" smart TV and a 40" smart tv both with back light out are about to get died and sold for 150$-250$ minimum on FB market place and/or offer up. This video helped me out a lot!!
A cheap repair that can literally save people hundreds or possibly thousands, bridge out the dead led with a few cents worth of wire and solder, it's a shame so many people would just throw the set away. Great repair as always.
Send me a set of 3 strips for a dollar! You can't just replace a single LED. There is no gain doing that. First of all you can't easily remove those chips as they are bonded to the heat sink, and even if you do how are you going to bond the new one to the heat sink? You cant just solder one across it, as it will overheat in a few seconds and fail. Trust me on that one I tried that a few years ago. These are not the same type of LEDs used in light bulbs, and they also have the crap driven out of them. If you are going to change them then you need to order in the entire set for the panel otherwise you are no further ahead. This works, and I have 2 sets that have worked after jumping a bad LED for years. Just turn the brightness of the back lights down. 0.107 volts more across each LED is not going to hurt them. Usually why a single LED fails in the first place is not due to it being a bad LED. It is because it wasn't bonded properly to the heatsink at the factory and overheated. The rest that haven't failed are generally OK.
12voltvids your observation is high end and appreciated ,i started tv repairing my age 17and I didn’t know fully operation during that time but I know several thinks how to check all the active and passive devices.All the times i under stood observation is main things that will find all the issues.
A real backlight tester works really well, and they are dirt cheap. Mine has saved me hours of fiddling. They automatically adjust the voltage, and can be used for single LEDs or entire arrays. No jumpers, bare wires or alligator clips required. Also, the most common failure after repair is another backlight going bad, even after adjusting the backlight brightness down. Replacing individual backlights is not recommended because other backlights that may appear to be working perfectly can still be damaged and fail within a month. We always recommend replacing all the backlights as a kit. If the customer insists on just replacing the one failed LED, we only offer a warranty on that LED, and not on any of the other backlights. People have brought their TVs back up to three times before finally saying they will just purchase a new TV when, if they had of done it right and replaced all the strips their TV would stay repaired.
I don't fix tvs for customers. They are all my sets and they have all been fine. I give them away after they are fixed. The only ones I have done for "customers " which are friends I have done more as a favor and charged them perhaps 50.00. That is their limit when they bring them to me, so there is no way to replace all of them. When the backlight kit sells for 100.00 by the time it gets here and labour on top would push repair to a minimum 175.00. Nobody will spend that when a new one is 200.00. I don't accept tvs from people and the ones you see are generally mine. That is why I am so fast to condemn a set that has a bad processor without attempting to replace a board.
Thank you very much solder the power supply board and everything's working again I thought I was going to go all the way to the back lights I've bought an expensive tester at least I'm ready for the next repair once again thank you 55 inches is going into my bedroom now once again thank you
I know this is a few years old, but just wanted to say that when I replaced the LED strips in my Samsung, I used thermal tape to attach them to the metal back in hopes of dissipating more heat to hopefully longer. Over a year and so-far, so good!
Thanks a lot, I was able to fix my TV, just an hour of work, no need to wait weeks for new LED strips from china and you don't even notice the lack of one diod
Great repair, i could not see any dark spots, plenty good enough for a tv :-D. Leds do seem crap for that job, but i've seen quite a few cfl backlight monitors that lose a tube or even the h.v driver just dies on one output. Leds do seem to die far too early thought.
Originally, I watched your videos to learn some basics and have been successful fixing all kinds of stuff. Now I find myself watching you fix thing I could care less about. Officially, Im addicted to this channel. Does anyone know a good support group?
Nice simple repair. I did wonder about bridging the dud LED, but given the number of 'em in the circuit, and also that you've turned the backlight down somewhat, it should outlast the tv. Probably can't get the LED for love nor money either :-)
Thanks for the educated movie. I have one question please: What would be the cause for one stripe of LEDs to work not on full power ? The picture on the top part of my Samsung tv shows but looks dimmed or darker Thanks
Nice job. Thanks for the information. I'm looking at one (Samsung UN40H5003AFXZA) that the 150 volt LED supply won't work with the LEDs plugged in. I put 50 volts on each LED section, and two started bright, then went out. The last one works and according to my meter pulls 50 mA. The other two appear not to draw any current. I'm still suspicious of the power supply although I've found no "smoking" gun 🙂. Even though the two don't appear to pull any current, the power supply still fails when the LEDs are plugged in. Hmm. I like that you actually troubleshoot things. :) Okay (8/28/22), I replaced the LEDs and the power supply works. I would strongly recommend against placing 50 volts on any LED strip. I would start at about 24 volts, and sneak up on it. At about 3.2 volts, this type of LED is pretty close to maximum brightness, so for 13 LEDs, that's 41.6 volts maximum for 12 LEDs it's even less. There is a 150 volt supply for the LEDs (it measures closer to 180). What you may have missed is that Samsung put a [switch-mode] current regulator in the LED strips' return path, and it runs at about 25 % duty cycle. I measure about 103.5 volts across the LED set when operating. This works out to about 2.72 volts per LED, which makes sense. Thanks again for the information and video. I'm not convinced this one has adjustable brightness.
When you connect the 50V to test the leds, do you set current limiting on your bench supplies to keep from smoking the leds? Or is there something downstream that limits the current? Great vid BTW. I have a ~2011 Samsung 55 incher and the right half of the screen is dark, so I suppose the led arrangement is different for that model. I will find out when I take it into surgery.
One thing that slightly confused me is when testing the strips individually before tearing it all apart, you used 50V as source voltage. When removed, you used 30V. Does it really make a difference except for how bright it will get?
Could you probe the lighting string connector and check resistance or continuity rather than sending voltage down it? I don't have a bench power supply.
They got rid of plasma sets for 2 reasons. 1) they were pretty reliable, and 2) the sucked back a fair bit of juice, but they shure looked good. I have several plasma sets here. A few the panels are slowly starting to fail, but the rest of them look great and they are 10 years old and older.
Remember the phrase, "getting the bugs out?" Got him out at 11:01. When I worked on TVs back in the late 60's, a lot of them were still using vacuum tubes. I'll never forget one TV I opened up and 100's of cockroaches started running away. They probably liked the heat from the tubes and enjoyed eating the paper on transformers and the wire sleeves. Disgusting, I made sure to bill the customer for a can of raid. When I change my LEDS, I'm going to use a heat gun to soften the double sided tape and avoid tearing the diffuser. Might also be able to heat it again to reattach.
I guess you went where not many TV repairmen go because I think they don't think it's worth fixing them. You've just proved them wrong. You've absolutely taught us so much. Now If I can remember those voltages, I'll be fine. I like the way you isolated each backlight. Are the backlight strips that expensive? Missing one isn't so bad. You made it look so easy but I know the experience you gave yourself and us it well worth the time. The reason people throw them away is because they don't know how to fix them, they don't have the money to fix them, they've been told that they're unfixable by a lot of TV repairmen. Plus, if the repairmen have to dig that deep, they are going to charge people an arm and a leg. Just a heads up on copyright law. If you have a business, you come under the fair use law and you can use the RU-vid feed for up to 30 seconds with any flack. Only if it's for your business for testing purposes now.
I stick to 8 seconds to be safe. In a shop environment this repair probably not worth it. Took a good 2 hours. At shop rates that isn't worth it. I charged them 100 and they were happy as a pig in mud. It was a free TV they got from the cable provider for signing up. Simple repair but most shops are not going to go through the trouble of disassembling the screen
@@12voltvids Yes I know but you, doing this out of your home, you can be a kind soul and I can see that. You're just a good person. That was a fascinating fix though even if it took awhile. Thanks for replying by the way.
@@larrypierce2777 I try to fix as many as possible and show how it's done. I make my money from the video advertising. So I can do these jobs that someone making a living from just could not do. If I still did this for a living I would have moved on real quick to the next and I would be living off the estimate charge like the majority of the shops still in business. I left the business in 2003 because I could see the direction it was headed and got out at the first opportunity.
I saw another video where, after changing the smd led with bad results (burning again) he decided to jump the burned led with an old fashioned led THT. What do you think?
I wish mine only had one LED out. I got the TV for free and decided I'd replace the individual LEDs instead of buying new strips. Start to finish took about 3 hours. Once you get into a rhythm with a hot air gun and some solder paste its not that bad. Cost me $12 and 3 hours.
These new tv's are not lasting very long just over 2 years old not good my plasma is 7 years old and still going strong. good fix though dave you saved another from the landfill.
Thanks for sharing this vide , I have same tv with 3 led were not working, i replaced the led bulb and all the leds were working, when i put the led strip back, As soon i connected the led connectorsame led bulb blow again. Do u think someting to do with power supply? Can u kindly help me with this. Thank u.
Are you able to use the LED tester to check all of the backlight LEDS from the connectors that plug into the power supply board? I took my TV apart again and took the panel outside and held up and looked through it using the sun as the light and I did not see any damage. I just do not understand why the backlights do not comeon. When I checked each tv individually they work. but, Idk how to check to see if they work as designed . I called Hitachi but they are closed today
How many strings of faulty LED christmas lights would you like me to send you. I have about a dozen. Long strings of 70 lights either the first 25 or the last 35 are out on most. 1 LED went open and the rest on the string went out too. If they short then the rest keep working, but if one goes open they all die. I have hundreds of dollars in broken lights. I put up so they look like crap so I can tall everyone, see how bad these are.
just had to stop at the power to the LED testing ! Well you know if the wire source is bad you get no power to the LED ! I found that out after i replaced to bad strips and went and did them all ! But make sure you supply wire is working first after you put in new LED!
I have a Samsung UN65H6203AFXZA Version no. MH01 that has had a new powersupply installed, but the same problem is still there. The red standby light is on full time and you cannot turn the tv on or off, no response with the button or remote. Where would you start looking for the problem? I'm very techincal and have repaired a few led tvs in the past. I hate to throw away a 65 inch 2 year old tv if I don't have to. Thanks!
How many volts are LED's commonly used in TVs? (Specifically Samsung 60") I guess what I mean is what is the voltage specification for a single LED? I've spent the last 2 days watching about 50 videos on the subject. This is the best one!
Tv has been running for years. Have done this a few times. I don't do much work on tvs anymore. They are so cheap that people just recycle them and get a newer cheaper better model..
I do not see the bad connections that you are talking about.. I creased and tore my reflector that was on the back of the TV and i do think you are able to see it when you get the TV back together. It was stuck down with double sided tape. This panel will not last long with this jumper in place because most likely the existing LEDs are already being over driven by too much current and the jumper will just make the current be higher for the remaining LEDs. You only made one connection from the good led bypassed over the bad LED?
i have the bn44-00775a board for the 60in. No backlights, replaced them still no backlights. Old ones just flashed off and on nonstop with several burned out. New ones check out fine but no backlight when i get them into the tv. I have picture and sound. Measure 12.3Vdc to main board but 380-400vdc to the led d+. Legend says it should be 326v. Any ideas what to try next?
I have an 55" Vizio LED 4K TV it's not bad it's a P series model with 125 local dimming zones it's pretty good for an non OLED TV. I never keep it at full brightness for two reason one I'm in kinda a dark room and full brightness would kill my eyes and two you don't need to watch on full brightness. The TV I have has three presets Low Medium High Off I usually keep it at Medium and is good. You can also adjust it your self if you click the preset to Off. I keep it at 75 it can go to 100 but just seems too bright it's nice these sets can get bright but that's to strong for my eyes.
Awesome video sir. I have the same problem with my Samsung tv. I will attempt to fix it and let you know. Look out for an update to this comment....cheers
Greetings, Thanks for the Vid. I have a HiSense 55" Roku TV It shut off the other day and would not turn back on. The standby light turns on when plugged in then dims and flashes once goes black for a couple seconds this sequence repeats continuously. I replaced the power board. Same issue. I measured the power from the USB port and the USB power seems to cycle with the light sequence. as if the TV is rebooting. Any ideas ?
Hi 12voltvids, thanks for the great video on showing us how to fix the no black light problem. I have a led tv also with no black light problem. But it is with a curve screen. Do you have any experience and/or suggestions in how to handle the screen? I am afraid it will break when I try to take it out before checking the leds.
As per your video I can see the logo of samsung through flash at the time of turning it on. I have a Samsung Led Tv 40 inch which has edge lit strip inside. I have checked the power supply board which has +led,nc,nc,-led which is connected to the edge lit led . The output voltage I can see is 89.9v from the board but the led strip is not turning on. After led drop the voltage is around 68 volt. I have tried power each led through a 9v battery and every led is turning on. How should I get it repaired ? please help.
Thank you! My two-year old Samsung QLED went out just out of warranty. It is going bright/dim/bright/dim. Now I know that this is the backlight going out (I'm no computer tech), and I had the brightness turned up to high. Bought a Bravia to replace it, but wondering if it is worth repairing the Samsung?
It might be around $50 to buy the replacement backlights but while replacing the backlights you might crack the lcd. My best suggestion is to throw it up on Marketplace and let someone pick it up that wants to try to repair it and no scrap it!
Hi there. Thanks for putting together this video. I have a u5002 with low backlight emits about half of what it used to be. Yes, I have running it at 20 to compensate for that. Is there a way to adjust it back up again? I thank you for your reply in advance.
Change the LEDs or buy a new TV. The problem with LEDs is they start to lose brightness the minute they are turned on. As the hours add up, they become dimmer and dimmer.Not much you can do about it. By 10,000 hours they will have lost about 50% brightness.
@@12voltvids I think what you are doing is ie. 15 lights1 of 3 strips, #13 is dead; therefore, you jump 12 to 13. video timestamp: diagnostic 13:54. timestamp: repair 15:18. Item terminology on my part may not be accurate but concept sb understood. Ie (LOL) the whatchamacallit that does the thing. Thanks for your time
@@petacare2512 I just jumper over the dead LED. They are all in series each is + - + - + -. The negative of one to the positive of the next. So I short the + and - together of the bad LED to that current can flow though the rest of the string. The power supply is a constant current source and will compensate for the bad LED.
@@12voltvids gotcha, thanks again. Trying to learn how to fix flat screen TV s. Save the earth. Things should last forever, like the used to. It is now a disposable world but, doesn't have to be. I guess that's marketing. Be blessed.
Mine was being fixed supposedly but when they put the new backlights it was burned again. The damage before was that half of the side of the TV has no backlights functioning. Now when they put the new ones it got burnt. Should this be between the main board and power supply? Please answer please please please sir.
I have the same Samsung tv, only 2 leds on the backlite strips are working, all other leds are out. Lot of information supplied but no mention of my possibility
