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Post your Samsung NU model series backlight failures and diffuser melt-downs here!

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    #21
    Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

    Samsung NU series is junk. Ive done many and always frustrated. I just dont mess with them anymore for fear of getting a burnt or cracked diffuser even tho the replacement leds are cheap. Now the only way I'll repair is if I get a NU for free no matter whats wrong with it, open it and check the diffuser. If its clean, thats great and go from there. This may sound crazy but Ive also cut down a larger diffuser to size using a Dremel Multimax and keeping the screen rotation in tact. Crazy, but last resort.

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      #22
      Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

      makes sense not messing with them, samsung needs to refund everyone who has an NU model FIRST, then maybe a few more models BUT definitely that shit one. I wonder how many houses will have to burn down before samsung does the right thing???
      Last edited by nomoresonys; 10-10-2022, 09:53 AM.

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        #23
        Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

        I think its is a question of profits over people. Samsung has turned into snake shit.

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          #24
          Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

          You nailed it Angelos, I haven't bought anything from samsung in a while, after seeing this DISGRACE, I'm crossing them off even consideration.

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            #25
            Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

            I see you tried to shift the LED from the melted spot. that is great tip
            but instead of doing the cutting the new LED strip why dont just order different length.
            I am saying this is because I just started to fix tv as hobby and I got 2 49 inches samsung professional display with burnt LED
            I opened one up just to makes sure the LED part number so I ordered them
            but like most of you guys have the same issue. melted diffuser.
            while waiting for the new LED. I just got another Samsung tv 50 inch with half backlight burnt. I opened up too and same issue burnt led and melted diffuser.
            but I compared the both led strips, they are almost identical except the length.
            so I am going to use the 49 inch led strip into the 50 inch
            so the LED Wont be on the melted area. and no need to cut any parts

            also I haven't tried yet. but have anyone tried to cut then polish the edge of the diffuser? I dont know if the diffuser has the same property as acrylic sheets? but if you see on YouTube, you can polished the edge by using fine sand paper then using torch to make it much clear. also is it possible to glue the crack using acrylic glue or windshield crack repair kit? I dont have a spare sheet to test. wondering if anyone can try.

            I will update when I get my new led strip.

            the more tv I tear down lately. now I see that samsung using just bottom led is the worst design ever.



            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.



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





            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.

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              #26
              Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

              I got one of these today un55nu6900 and threw it in the corner to clean out some old junk TVs. Then I had the idea to try and use a different frame and backlights since these keep having the same problem.

              Long story short I used the chassis and backlights from a un55mu6300. Put the screen in and main board from the nu series and powered it up. Works great and no longer have to worry about the backlights burning out and cracking/ melting the diffuser.

              This won’t help most people but any techs/ shops with TVs that have broken screens might find it useful.

              Comment


                #27
                Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                Originally posted by Storyteller12 View Post
                I got one of these today un55nu6900 and threw it in the corner to clean out some old junk TVs. Then I had the idea to try and use a different frame and backlights since these keep having the same problem.

                Long story short I used the chassis and backlights from a un55mu6300. Put the screen in and main board from the nu series and powered it up. Works great and no longer have to worry about the backlights burning out and cracking/ melting the diffuser.

                This won't help most people but any techs/ shops with TVs that have broken screens might find it useful.
                Great work. I assume you used all the diffuser screens from the 55MU?

                Comment


                  #28
                  Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                  Originally posted by handsworth View Post
                  Great work. I assume you used all the diffuser screens from the 55MU?
                  Yes, the mu is full array so different setup as the nu is edgelit

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                    #29
                    Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                    This thread will never die, the crap that samsung made lives on burning and cracking diffusers forever.

                    I took a NU 55 inch for repair, but warned the owner that it would not come back 100% because the cost of a new diffuser here is absurd + the shipping for something that big, and no 55 NU or similar TVs with cracked screen for sale around here.

                    The cracks were already visible, half of the screen was dark, so one of the LED strips died.

                    Upon opening this hellish screwless design and having almost a heart attack to take the panel off without damaging it, I was met with a big meltdown on the left side(from the front) and some cracks on the acrylic.

                    I just replaced the leds and inverted the diffuser thinking it would produce a good picture, bad mistake since it was horrible, all bright on the bottom and very dark in middle to top.

                    Dismantled the TV again and found out that sliding the diffuser to the non burnt bottom parts made it much better, so I took a plier and for 40 minutes painstankingly clipped around 1.2cm of the left side of the diffuser, that did it, only the small cracks were visible, but the lighting was very uniform, the LED strips at bottom of the TV heat up a lot.

                    I enabled energy saving to low and kept backlight at 40 for all inputs, and told the owner to not raise it or it would happen again and be even worse to repair.

                    PS: the third picture is before clipping, and the last is the final result.
                    Attached Files
                    Last edited by Biruslapio; 04-09-2023, 09:12 PM.

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                      #30
                      Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                      Samsung model (Series 6) UN43NU6900FXZA. Turned it on this afternoon (After watching this morning) and there wasn't any picture or sound. Unplugged it for a short time and the sound came back but no picture. Used the flashlight test to check the backlight and there was a picture, just no backlight. This happened all of a sudden. This mainboard has all the components built in.

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                        #31
                        Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                        Being a NU model and 43 not real big, I would carefully take it down to backlights to check condition of the diffusers and test the backlights while there, could be bad backlight or connection in backlight circuit. Always remember to run these models on the lowest backlight setting possible.
                        Last edited by nomoresonys; 05-01-2023, 05:48 AM.

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                          #32
                          Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                          Originally posted by Biruslapio View Post
                          ....
                          Dismantled the TV again and found out that sliding the diffuser to the non burnt bottom parts made it much better, so I took a plier and for 40 minutes painstankingly clipped around 1.2cm of the left side of the diffuser, that did it, only the small cracks were visible, but the lighting was very uniform, the LED strips at bottom of the TV heat up a lot.

                          I enabled energy saving to low and kept backlight at 40 for all inputs, and told the owner to not raise it or it would happen again and be even worse to repair.

                          PS: the third picture is before clipping, and the last is the final result.
                          Fantastic!

                          Do I understand that the LED's are no longer in the holes and that that works ok?

                          Thanks!

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                            #33
                            Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                            Yes, they were not touching the burnt spots, rather the best thing to do is to position them in the middle between the spots, cutting that 1.2cm did it.

                            There's an easier way to do it, dislocate the LEDs instead, but I don't know if the tv frame can accomodate them properly if you displace them that much. In my case they were already glued very strongly so taking them out would probably damage the newly installed "strip".

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                              #34
                              Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                              Originally posted by alfatv View Post
                              It looks like that source does sell them! But it is probably impractical to buy from them because they are in Russia.

                              However, it looks to me as if the diffusers (aka Light Guide Plates) they sell are actually made in China.

                              This may be the source
                              https://www.rinalgp.com/led-backligh...lgp-panel.html
                              and
                              https://www.rinalgp.com/diffuser-pla...ser-sheet.html
                              or
                              https://www.aliexpress.us/item/3256803865775175.html?

                              Now normally they only sell in quantity but maybe we can find some way......

                              Here is one store in Malaysia selling some of them
                              https://www.lazada.com.my/products/l...479735322.html
                              Last edited by Comintel; 08-13-2023, 05:34 PM.

                              Comment


                                #35
                                Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                                Thanks! I will give it a try with the LED shifting approach then and cross my fingers!

                                Comment


                                  #36
                                  Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                                  I think I may have found the Samsung 43 inch LGP / Diffuser part number.

                                  BN61-15663A

                                  (please verify before ordering).

                                  https://samsungpartsusa.com/search?q=BN61-15663A
                                  https://fr.shopping.rakuten.com/offe...a-samsung.html

                                  It costs under 30 Euros in Europe but over $90 in the US. Obscene markup!

                                  The 55 inch looks a lot cheaper so maybe the 43 inch pricing is an error.
                                  Last edited by Comintel; 08-17-2023, 04:52 AM.

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                                    #37
                                    Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                                    I would not spend any money on this set. Even if you replace it and the leds the problem will happen again. It’s not worth it.

                                    You know the sayin “you can polish a turd but it’s still a turd“

                                    Comment


                                      #38
                                      Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                                      It only happens if the leds are driven on 100%, like the default config does.

                                      I know someone who owns a 55NU7100 since 2019, I noticed even back then that the bottom of the tv was quite warmer than usual, and decreased the LED level to 14 (from 20), it's still running fine, avoided a major issue there and these problems were not even documented back then.

                                      Comment


                                        #39
                                        Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                                        55NU badly melted I was able to clean it up a bit but the crack was a complete let down, customer was happy to get the set going though.

                                        There is a company I buy led backlights off that have started making replacement reflector sheets but only ship 8 or 10pcs at a time.
                                        I don't really fix enough Samsung's to justify buying so many
                                        Attached Files

                                        Comment


                                          #40
                                          Re: Post your Samsung NU model series backlight failures and diffuser melt-downs here

                                          Originally posted by zwarder View Post
                                          55NU badly melted I was able to clean it up a bit but the crack was a complete let down, customer was happy to get the set going though.

                                          There is a company I buy led backlights off that have started making replacement reflector sheets but only ship 8 or 10pcs at a time.
                                          I don't really fix enough Samsung's to justify buying so many
                                          Since you are in the UK, would this be the correct part?

                                          https://www.onbuy.com/gb/p/samsung-b...65a~p57513537/

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