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Old 06-11-2021, 02:20 PM   #1
DXseekerMO
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Default Post your Samsung NU model series backlight failures and diffuser melt-downs here!

So I started this thread for all of us TV fixers to post our Samsung NU model series backlight failure and resulting main diffuser melt-downs. Please do post pictures!

Either Samsung needs to recall these TVs for this problem or provide owners with updated parts that will not repeat the same failure!

I will start:

Samsung UN40NU7100FXZA, left-side backlights failed, left side of main diffuser and reflector sheet behind it melted in the shape of the LEDs below it. Picture #1 and 2 below.

Samsung UN65NU7100FXZA, left-side backlights failed, left side of main diffuser melted in the shape of the LEDs below it, reflector sheet undamaged. New backlights installed. Left lower side of picture has bright spot where the main diffuser is melted. Picture #3 below
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File Type: jpg IMG_20210611_151057517_BURST001.jpg (695.5 KB, 157 views)
File Type: jpg IMG_20210531_212420122_BURST000_COVER_TOP_A.jpg (277.9 KB, 158 views)
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Old 07-20-2021, 12:05 PM   #2
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

I have the same issue with a 65 inch Samsung edge lit TV. Has anybody tried to install the diffuser panel with the damaged part at the top? Just wondering what it would look like. My diffuser panel isn't cracked, just melted.

Also, has anybody tried cutting of the bad section of the diffuser panel.

Or, has anybody found a fix or a replacement diffuser panel anywhere?

Thanks in advance for any help with this.
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Old 07-24-2021, 06:07 AM   #3
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

Quote:
Originally Posted by JunkmanJimbo View Post
I have the same issue with a 65 inch Samsung edge lit TV. Has anybody tried to install the diffuser panel with the damaged part at the top? Just wondering what it would look like. My diffuser panel isn't cracked, just melted.

Also, has anybody tried cutting of the bad section of the diffuser panel.

Or, has anybody found a fix or a replacement diffuser panel anywhere?

Thanks in advance for any help with this.
Can anybody help me with this, please?
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Old 07-24-2021, 06:25 AM   #4
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

I've done it several times with this NU series tv. When the bottom of the thick panel has burn marks, I have turned it so the burns are at the top. Turn the diffuser 180 degrees. Do not flip it. I've done it on 50 and 55" models with great success except for in one case. The screen was a little dark at the top but I could blame this on the cheaper leds I bought. Picis of UN55un7100 with burns at top. Looks great.
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Old 07-25-2021, 10:24 AM   #5
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

Thank you, handsworth. I will give it a try. One side of mine warped on the left side causing a bubble type warp so I'm afraid that might be seen but I guess I won't know until I try it. Thanks again!
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Old 10-24-2021, 05:52 AM   #6
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

Quote:
Originally Posted by handsworth View Post
I've done it several times with this NU series tv. When the bottom of the thick panel has burn marks, I have turned it so the burns are at the top. Turn the diffuser 180 degrees. Do not flip it. I've done it on 50 and 55" models with great success except for in one case. The screen was a little dark at the top but I could blame this on the cheaper leds I bought. Picis of UN55un7100 with burns at top. Looks great.

Hi, I have ran into this same issue as you described on the UE55KU6400 model. Same bottom edge lit with diffuser burnt. I need to add that when rotating by 180deg there is a reflective film at the edge that needs to unpeel and fit on the opposing edge.
I got a Picture brighter at the lower part. Am not sure if its due to the LED quality. Seem very very bright at the bottom and am now 50% backlight settings.

Have you ever sanded out and polished the burnt edge?

Could it be the diffuser of these models is not linear that is originally reflect more at the top?
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File Type: jpg 20211023_155121.jpg (636.5 KB, 94 views)
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Old 11-15-2021, 10:44 AM   #7
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

UN48JS8500, MFD May 2015, repaired October 2020. Had no working backlight when I got the TV. Replaced the LED strips and had to dremel grind the blackened burn/melt marks on the diffuser. Has some issues with image but is a decent garage TV now. Would buy a diffuser if I could find one.
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Old 11-25-2021, 07:00 AM   #8
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

UE43NU7192 burned difuser...replaced difuser and leds
Barely cost efective repair....

UE49NU7172 replaced leds and difuser turned 180 deg(not flipped), like Handsworth said.Picture acceptable.

another 43NU7192 badly burned difuser... changed,final result like "alltvrepairs" said, I got a Picture brighter at the lower part. maybe my fault, maybe had to turn difuser 180deg, but customer accepted and I didn't touch it after that.
Barely cost efective repair....

stay away from this NU's, I do not accept them any more for a repair...

mytwocents
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Old 12-01-2021, 06:15 PM   #9
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

I use a dremel cutting wheel to gently grind away the burnt spots on the edge of the diffuser. Nothing can be done if it's cracked, but it doesn't look too bad considering how dark these sets are to begin with.
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Old 12-17-2021, 08:31 PM   #10
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

43NU here, the left part of the screen is dark and on the remaining part some LEDs are dead.
As you can see in attached picture, there are bumps on thick glass from LED's and also back reflector is warped.
i have 43MU with broken screen and considering swapping NU parts into this one.
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Old 12-19-2021, 01:12 PM   #11
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

I wanted to post this also about Samsung tvs of the same design. I wanted to repair a UN65JS8500 which I thought was just bad leds. Even though its not the NU series, the diffuser panel and leds are very similar. I came to the conclusion that this tv is unrepairable before dismantling it, and will part out on Ebay. The close up pics in the video is what you will probably find in your NU series also.

https://www.youtube.com/watch?v=3mV7...l=Paul%27sTVCo
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Old 12-31-2021, 06:41 PM   #12
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

Here's one I just opened up.
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Old 03-17-2022, 11:39 AM   #13
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

First of all i feel i must state it's a shame of Samsung to design and sell this kind of crap, in my case a UE43NU7122k tv, but what can you do...

So I'd like to share a good solution i thought of and tested successfully (perhaps it's meant more for the casual enthusiast rather than the professionals, as it requires small modding).

So to the point.

The diffuser is definitely directional. It allows more light to go through at the top and less at the bottom, to compensate for the bottom sided backlight.
When you rotate it, the bottom quarter of the picture ends-up super bright, and the rest gradually towards the top ends-up very dimmed and dull (like others have already posted here).

In my case the diffuser was badly burned above each led, and cracked in 3 places (5-6 cm cracks). But, as others also found out, there is nothing you can do about the cracks.

So my solution is not to rotate the diffuser, but instead, first grind out the burns with a dremmel (otherwise a brown tint will be seen in the picture), and most importantly "shift" the new backlight strips a little (1-1.5 cm) so each led ends up in the middle between the burns.

This requires modification to the metal frame where the strips are installed. You have to cut one of the aluminum end stops for the led-strips (left or right doesn't matter), and the aluminum around the connector so the strips can be shifted left or right. See the pics of the modification. The blue marker shows the original location of the leds, and as you can see now they are centered between them.

IMG_0189.jpg

(on the picture above i have obviously trimmed the other side, so my leds are shifted to the right...)

IMG_0190.jpg

backlight-strip.jpg

Additionally (picture above) it's necessary to trim one of the led strips at the end towards the shift. You can trim about 6-7 mm with a dremmel, been careful not to break the cirquit.

This way the leds are illuminating the diffuser properly, so the burn marks have no effect, and the result is near perfect.

If you additionally have cracks like me, those are impossible to correct. But keep in mind they will give exactly the same effect no matter if they are at the bottom or the top of the screen (bright spots).

PS i also suggest the backlight current limit mod explained here: https://www.elektroda.pl/rtvforum/to....html#19771530 (1 resistor replacement), to avoid the same thing from happening again. The brightness reduction is minimal.
Of course the resistor values perhaps only apply for the UE43NU7122K like mine, but the values for other models could be adjusted.

Last edited by Asxetos21; 03-17-2022 at 12:02 PM..
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Old 03-17-2022, 04:10 PM   #14
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

Quote:
Originally Posted by Asxetos21 View Post
First of all i feel i must state it's a shame of Samsung to design and sell this kind of crap, in my case a UE43NU7122k tv, but what can you do...

So I'd like to share a good solution i thought of and tested successfully (perhaps it's meant more for the casual enthusiast rather than the professionals, as it requires small modding).

So to the point.

The diffuser is definitely directional. It allows more light to go through at the top and less at the bottom, to compensate for the bottom sided backlight.
When you rotate it, the bottom quarter of the picture ends-up super bright, and the rest gradually towards the top ends-up very dimmed and dull (like others have already posted here).

In my case the diffuser was badly burned above each led, and cracked in 3 places (5-6 cm cracks). But, as others also found out, there is nothing you can do about the cracks.

So my solution is not to rotate the diffuser, but instead, first grind out the burns with a dremmel (otherwise a brown tint will be seen in the picture), and most importantly "shift" the new backlight strips a little (1-1.5 cm) so each led ends up in the middle between the burns.

This requires modification to the metal frame where the strips are installed. You have to cut one of the aluminum end stops for the led-strips (left or right doesn't matter), and the aluminum around the connector so the strips can be shifted left or right. See the pics of the modification. The blue marker shows the original location of the leds, and as you can see now they are centered between them.

Attachment 259134

(on the picture above i have obviously trimmed the other side, so my leds are shifted to the right...)

Attachment 259135

Attachment 259140

Additionally (picture above) it's necessary to trim one of the led strips at the end towards the shift. You can trim about 6-7 mm with a dremmel, been careful not to break the cirquit.

This way the leds are illuminating the diffuser properly, so the burn marks have no effect, and the result is near perfect.

If you additionally have cracks like me, those are impossible to correct. But keep in mind they will give exactly the same effect no matter if they are at the bottom or the top of the screen (bright spots).

PS i also suggest the backlight current limit mod explained here: https://www.elektroda.pl/rtvforum/to....html#19771530 (1 resistor replacement), to avoid the same thing from happening again. The brightness reduction is minimal.
Of course the resistor values perhaps only apply for the UE43NU7122K like mine, but the values for other models could be adjusted.

Thanks for sharing. But where is the after pic so we can see how the picture looks
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Old 05-12-2022, 02:16 AM   #15
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

I know it's a Samsung thread, but...

LG 55UH850V here.
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Old 06-16-2022, 04:12 PM   #16
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

Just did a UN43NU6900F. Strips look like they use the more standard rectangular LED vs the high temperature, high heat square ones that tend to melt the light spreading panel. No panel damage on mine, just one side dark. A little tricky taking apart with the screwless back cover. The metal leg supports are snapped in and can be popped out. The panel board shield just snaps in as well.

I also stumbled on aliexpress replacement light spreading panel sheets but it was min 10 piece order IIRC. Can't find the link now.
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Last edited by neilc6; 06-16-2022 at 04:25 PM..
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Old 06-24-2022, 04:53 PM   #17
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

Here are a couple of pics of mine. I was watching on a hot day and I guess it was the last straw for the diffuser and it just cracked. I am not even going to bother opening it because it's not like you can buy a replacement diffuser screen. I am going to take this as a very expensive lesson to not buy Samsung TVs anymore.

p.s. my model is the UN65NU8000

Note: The pictures are of just a white image being displayed and have been flipped upside down after the upload for some reason
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Old Today, 03:23 PM   #18
neilc6
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Default Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

Showed up in my Aliexpress recommendations.

https://www.aliexpress.com/item/1005004049744840.html
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