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Old 02-14-2021, 04:28 PM   #1
DXseekerMO
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Default Samsung UN40NU7100FXZA....MELTDOWN!

Hello everyone. So this time I come less asking for advice and more with a warning. As far as I can tell this is the first post for this model.

I picked up a Samsung UN40NU7100FXZA from a supplier the other day, build date January 2020. I checked it before purchase to find there were only a few LEDs working. Where they were the diffusion of light looked "abnormal" but the picture was obviously still there.

I disassembled the TV. See what I found in the pictures below.

The LEDs upon the right side of the TV had obviously been so hot they melted themselves in to the main light diffusion panel! You can see their impression in the diffuser! Furthermore the lower part of the diffuser is heat deformed and appears partially melted! There are cracks radiating in to the diffuser from a couple of the LEDS!

Based on the design I see I can also see every TV of this model having this problem.

This said I have one question....does anyone believe an LED current adjustment and turning the backlights down are enough to prevent a repeat failure?

I'd say with this model if you see ANY CHANGE in the diffusion of light at the bottom of the screen you may be having this problem. Also, I think once the change in diffusion has started the main diffuser panel is already damaged to the point the TV isn't worth fixing.

In the absence of a fix the most reasonable work-around appears to be turning the backlights down to the lowest possible practical setting.

It's sad to see Samsung not thinking ahead. A potential failure like this should have been obvious.
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File Type: jpg IMG_20210214_140232468.jpg (596.3 KB, 57 views)
File Type: jpg IMG_20210214_140249838.jpg (720.8 KB, 40 views)

Last edited by DXseekerMO; 02-14-2021 at 04:30 PM.. Reason: I ain't got no good english
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Old 02-14-2021, 09:22 PM   #2
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

See lots of NU failures on the tvrepair subreddit. Haven't tackled one yet.

Replacement strips appear fairly cheap due to the design. Can you flip the sheet so the LEDs are shining into a clean edge?

https://techhometravel.com/samsung-n...ight-failures/

Last edited by neilc6; 02-14-2021 at 09:40 PM..
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Old 02-15-2021, 12:41 AM   #3
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Sad, 1 years old TV that failed due to bad design, poor thermal management.
If you can get it running again I would turn down the backlights to 50%.
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Old 02-15-2021, 01:05 AM   #4
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Can you turn the diffuser sheet around or is it too damaged?
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Old 02-15-2021, 07:44 AM   #5
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Quote:
Originally Posted by neilc6 View Post
See lots of NU failures on the tvrepair subreddit. Haven't tackled one yet.

Replacement strips appear fairly cheap due to the design. Can you flip the sheet so the LEDs are shining into a clean edge?

https://techhometravel.com/samsung-n...ight-failures/
I see arrows at the bottom of the diffuser pointing up. That leads me to believe this diffuser is directional, however I do have almost 50 different main diffusers from other TVs. I thought aboot trying a couple of those and see what happens. May have to cut some down to fit.

Quote:
Originally Posted by budm View Post
Sad, 1 years old TV that failed due to bad design, poor thermal management.
If you can get it running again I would turn down the backlights to 50%.
That's kinda what I figured. budm how about a current adjustment on the PS?

Quote:
Originally Posted by Wilderone View Post
Can you turn the diffuser sheet around or is it too damaged?
It is real bad. I think if I try to use it there will be artifacts on the screen.

Also the reflector sheet under the main diffuser has LED witness marks melted in to it as well!

Honestly I'd like to have 2 TVs of this model...one to poop on and one to cover it up with....like a Cat does a turd in a sandbox
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Old 02-15-2021, 08:23 AM   #6
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

from the distances between LEDs they look double LED high power at least 120 200 lumen..
the first solid plate are reflector .. then coming on it the diffuser, the reflector side opposite to the LEDs strings it had reflection type to keep the light inside.. unlikely the side which faced the led which are transparent.. no way to flip it..

i would suggest to replace all the LEDs at once with new one.
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Old 02-15-2021, 09:54 AM   #7
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Quote:
Originally Posted by Diah View Post
from the distances between LEDs they look double LED high power at least 120 200 lumen..
the first solid plate are reflector .. then coming on it the diffuser, the reflector side opposite to the LEDs strings it had reflection type to keep the light inside.. unlikely the side which faced the led which are transparent.. no way to flip it..

i would suggest to replace all the LEDs at once with new one.
Yes for sure, and I already have some ShopJimmy LEDs ready for it, already heat-sink mounted.

I also recycle TVs, and I have some of these main diffusers and reflector sheets out of other Samsung edge-lit TVs. I thought about trying to swap in one of these. I'd have to cut the diffuser and reflector sheet down since these are from 55" TVs.

If I do that I'm less concerned about the reflector sheet, I should be able to match the color ok. The main diffuser may be a different story. I think it may be hard to match the "polarization" of the diffuser and the picture may not be right afterwards, like the presence of artifacts at the bottom of the screen.

If anyone believes swapping and potentially cutting down a main diffuser would work I can post pictures (and hopefully a model/panel part#) if anyone is interested?
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Old 02-15-2021, 10:25 AM   #8
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Quote:
Originally Posted by DXseekerMO View Post
If anyone believes swapping and potentially cutting down a main diffuser would work I can post pictures (and hopefully a model/panel part#) if anyone is interested?
i see, so you are going to replace the strings complete with used one.. i meant only the LEDs to replace LOL

cutting will not work.. as i wrote, if the edge LED are downside. mean the up side of the reflector have reflection Type glued on the edge top or some do it by coating so you can't cut it from this side... and if you are going to cut from downside ( which facing the LED you need to smoothing the edge surface after cutting to let it transparent not easy work... LOL. other side left or right no problem by cutting.

Last edited by Diah; 02-15-2021 at 10:32 AM..
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Old 02-15-2021, 11:10 AM   #9
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Quote:
Originally Posted by Diah View Post
i see, so you are going to replace the strings complete with used one.. i meant only the LEDs to replace LOL

cutting will not work.. as i wrote, if the edge LED are downside. mean the up side of the reflector have reflection Type glued on the edge top or some do it by coating so you can't cut it from this side... and if you are going to cut from downside ( which facing the LED you need to smoothing the edge surface after cutting to let it transparent not easy work... LOL. other side left or right no problem by cutting.
It sounds like the only way to go is a new diffuser, or at least one the same size.

Guess I'll go see what I have later.
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Old 02-15-2021, 02:43 PM   #10
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Well after "thinking 4th dimensionally" for a bit I decided to petition a well-known parts supplier for a main diffuser and reflector sheet. One of the guys in customer support asked if my email was good and said they would let me know.

I'm not posting the supplier's name, just in case they aren't able to help me.

I also suggested this will become a pattern failure and there may be a market for these items.

Like I said, I really believe every TV in this one's size and family will eventually melt down like mine and others. I also wouldn't be surprised if these get recalled for this problem!
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Old 02-15-2021, 03:43 PM   #11
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

It's unlikely we will see a recall from Samsung Electronics since they are busy paying Attorney's to keep the family members out of prison and having to pay Samsung Display enough for their panels to feed their need to pump out garbage like this and other models with overheating led's causing damage to the diffuser's. When a customer brings in a Tv to me for repair and they say "I could smell plastic" I simply pull the bezel, take pictures, and tell them to buy another Tv because it's a Fire Hazard at that point. I've seen this in 9000 series Samsung's and it sickens me to see the lack of engineering especially in edge lit Tv's.
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Old 02-15-2021, 03:55 PM   #12
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Quote:
Originally Posted by brucetv View Post
..
he will remain in prison to finish his charge.. but dont blame companies ,, blame your country polices when they dont protect their folks.. we have here now all MUST give 3 years guaranties. you are still in ONE YEAR. but this is also good for you other wise all of you will shutting down lol
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Old 02-15-2021, 04:10 PM   #13
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Quote:
Originally Posted by brucetv View Post
It's unlikely we will see a recall from Samsung Electronics since they are busy paying Attorney's to keep the family members out of prison and having to pay Samsung Display enough for their panels to feed their need to pump out garbage like this and other models with overheating led's causing damage to the diffuser's. When a customer brings in a Tv to me for repair and they say "I could smell plastic" I simply pull the bezel, take pictures, and tell them to buy another Tv because it's a Fire Hazard at that point. I've seen this in 9000 series Samsung's and it sickens me to see the lack of engineering especially in edge lit Tv's.
Hello Chickendale AR! I'm about 70mi from you near Springfield.

And they're going to keep pumping out crap until the US requires 3 year warranties.

My biological father worked for Zenith. I still have a 1965 hard-wired Zenith console I use for E-Skip reception of analog TV stations. It had to have the yoke replaced in it in 1974....but it STILL WORKS!

Samsung...the junk goes in before the name goes on
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Old 02-15-2021, 04:27 PM   #14
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

I take it they're not selling samsung tvs in Germany then?
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Old 02-15-2021, 04:37 PM   #15
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Only to those who have "SUCKER" emblazoned upon their foreheads.

And that goes worldwide! lol
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Old 02-15-2021, 05:16 PM   #16
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

LOL, I have a 2007 ccfl samsung that has only needed a mainboard and about 5 or 6 caps on the powerboard, very nice picture imo, better than the 2015 sammy 55 un edge lit that I have 40 bucks total in which is the one that will probably burn up, just glad I only have 40 in it, for sure would not buy a new sammy.
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Old 02-15-2021, 05:18 PM   #17
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Mine's a UN55KU6300FXZA...$40.00 invested and 2 years running! It has a super hot tuner too....which is GREAT for DX!
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Old 02-15-2021, 05:21 PM   #18
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Quote:
Originally Posted by nomoresonys View Post
I take it they're not selling samsung tvs in Germany then?
It means you can buy crap with longer warranty, instead of making good products so you know you do not have to worry about repairing them for a long time if you make it right in the first place.
Passing law does not make company to make good reliable products, people stop buying them will make them improve the products. I.E. look at car for example.

Last edited by budm; 02-15-2021 at 05:24 PM..
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Old 02-15-2021, 05:22 PM   #19
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

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It means you can buy crap with longer warranty, instead of making good products so you know you do not have to worry about repairing them for a long time if you make it right in the first place.
+1 00000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000000000000 00000000000000000000000000000000000000000.

lol
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Old 02-15-2021, 05:34 PM   #20
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Default Re: Samsung UN40NU7100FXZA....MELTDOWN!

Quote:
Originally Posted by nomoresonys View Post
I take it they're not selling samsung tvs in Germany then?
they do .. and they push 3-4 model in year.. but the shit they do now by earning money from adds on the tv, beside they stooped all free app which support IPTV, but still of course way to install them.

we still remember how Korean brands war.. for example before few years at house electronic exhibition in Berlin, when the CCTV catch LG CEO how he damaged one of samsung washing machine door LOL
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