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Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

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    Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

    so i got this tv to fix and the guy says it turns off and on over and over again.
    i was able to see this behavior after running it for a couple of hours. at first it seemed fine. i did notice in the lower left of the screen though, there is an area that is not as brightly lit, indicative of possibly some LED issues...its only really noticible on a white screen though. during a regular movie you hardly can tell.
    feeling on the back of the tv, i dont notice either of the boards getting very hot, but it seems like a heating issue since it takes 2 hours to fail...
    once its in "fail mode" and turning off and on, what should i look for to tell me if its the main board, or the PSU...or could it actually be bad LED's would that cause the tv to shut off? i know some tvs keep running and you hear the sound and can even see the image with a flashlight, but do some tv's just completely turn off if the backlight goes out?
    Don't fear the repair...

    #2
    Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

    Yes it can. If the string is shorting to ground. The es series uses a backlight controller that goes into protection. If you want to verify this, Disconnect the Cable that feeds the main board from the power supply. Then plug the TV and in see if the back lights come on and flicker or not. Also look and see if this area is still dim. You most likely have a failed backlight and I believe the series also uses edge lit backlighhting.

    Also leave the back off and wait until the TV starts to power cycle then turn it off immediately disconnect the backlight string from the power supply and then turn it back on and run it some more. Watch to see if it starts power cycling again
    Did I leave the soldering iron on?

    Comment


      #3
      Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

      yeah i was looking at it some more and i realized that this tv does have the awesome feature of "self testing" if you start it up without the mainboard connected. the backlights do flicker but i find even when i disconnect the LED string from the PSU, that the PSU is still power cycling....pretty sure ive got a bad PSU here...could a minor LED problem cause a PSU to fail? will installing a new PSU only fix the problem for a little while until it burns up the new PSU?
      Don't fear the repair...

      Comment


        #4
        Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

        Well I'm not entirely sure. You should take some voltage measurements when your power supply is power cycling.

        Does the power supply power cycle continuously no matter what even cold if the led's are not connected?

        It could be a power supply but it could also be a main board problem as well in the only way to tell would be to force feed PS on resistor with 5v And when the TV power cycles if it does still listen for the power supply tripping on and off. If power supply stays live but the TV starts resetting It's a main board
        Did I leave the soldering iron on?

        Comment


          #5
          Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

          Try running the TV with Backlights level (not Brightness) as low as possible to see if it will run longer. If I remember correctly you should also re-solder all the transformer legs especially the one on the rivet through hole.
          Never stop learning
          Basic LCD TV and Monitor troubleshooting guides.
          http://www.badcaps.net/forum/showthr...956#post305956

          Voltage Regulator (LDO) testing:
          http://www.badcaps.net/forum/showthr...999#post300999

          Inverter testing using old CFL:
          http://www.badcaps.net/forum/showthr...er+testing+cfl

          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
          http://s807.photobucket.com/user/budm/library/

          TV Factory reset codes listing:
          http://www.badcaps.net/forum/showthread.php?t=24809

          Comment


            #6
            Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

            i was able to see the voltages dropping and restarting while the psu was all by itself, it doesnt need to be tricked to turn on. it will self test with no boards connected just power plugged in, so i know at least i have a bad PSU... will try resoldering transformer and see if that helps.

            also after letting it sit overnight, and trying to turn it on in the morning, i see it gets into power cycling within a couple minutes now instead of hours. maybe the board has broken down more because of all the testing i was doing on it last night?
            Last edited by triplefour; 12-15-2017, 03:01 PM.
            Don't fear the repair...

            Comment


              #7
              Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

              budm when you say resolder, do you mean completely remove all existing solder? or just reflow it? and which transformer?
              Attached Files
              Last edited by triplefour; 12-15-2017, 05:14 PM.
              Don't fear the repair...

              Comment


                #8
                Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                TS801S and the next one below it, you can see the through hole rivets on the legs, I use flux and add just regular solder to the joints.
                Any through hole rivets I will re-solder.
                Never stop learning
                Basic LCD TV and Monitor troubleshooting guides.
                http://www.badcaps.net/forum/showthr...956#post305956

                Voltage Regulator (LDO) testing:
                http://www.badcaps.net/forum/showthr...999#post300999

                Inverter testing using old CFL:
                http://www.badcaps.net/forum/showthr...er+testing+cfl

                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                http://s807.photobucket.com/user/budm/library/

                TV Factory reset codes listing:
                http://www.badcaps.net/forum/showthread.php?t=24809

                Comment


                  #9
                  Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                  well budm i did what you said, and reflowed the solder just adding flux and more solder to the through hole pins on both the transformers and one other pin on pc8025 that looked corroded, and the tv has been running for hours now without issue. still want to test it a bit more but its definitely looking good. thanks again for the tip!
                  Don't fear the repair...

                  Comment


                    #10
                    Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                    ahh i spoke too soon. that night it stayed on fine for 5 hours straight but the next day when i was testing it again it started crapping out after 2 hours and going into the shutdown loop it was too good to be true!
                    Don't fear the repair...

                    Comment


                      #11
                      Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                      well i set this tv aside for a couple months but im back looking at it again. first thing i did was power it up again to verify everything was still behaving the same way, and it was. starts right up no problem, and i can see the LED's are not lighting on the bottom half of the left edge strip. i didnt bother to run the tv for hours again to see it go into power cycling, as i know thats whats going to happen. so i went straight for repairing the LED strip.
                      so i disassembled the panel, got to the afflicted strip and saw that the bottom two LED's are busted off but still there. the LED's test fine, so i proceded to solder them back in place (which is not easy let me tell you. these are the worst kind of edge lit LEDs, where the solder pads are on the edge of the LED instead of the back.)

                      apparently the strip is 60 LED's and is broken into 2 halves. in my case, the 2 bottom LED's were missing, causing the rest of the 28 LED's not to light.

                      so after many tries i was able to get the strip working somewhat stable. if i flex the area, sometimes it drops out again, but i am able to use my LED tester and get it to light up all the LED's and stay lit if i just dont touch anything.
                      so i was going to leave it like that and not fully reassemble the panel but just enough to test it for a few hours and see if the PSU goes into power cycle now that the LED's are fine...

                      and what happened? of course, now the power supply is behaving completely different. i didnt even do anything to it! but now it doesnt light the backlight at all, and even with the strings disconnected from the PSU, i get 0v on all 3 pins for the right strip and a voltage fluctuating between 255 and 265 on the two + pins for the left strip, and 0v on the - pin
                      makes no difference whether the LED strips are connected or not. so this is where i'm at now
                      fixed the LED's and now i have a new problem on the PSU....
                      whack a mole! i dont give up easy though, so now i'd like to track down whats going on in this PSU and fix it!

                      im kicking myself for not taking voltage measurements on this tv when it was power cycling
                      Last edited by triplefour; 03-14-2018, 02:51 PM.
                      Don't fear the repair...

                      Comment


                        #12
                        Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                        " i get 0v on all 3 pins for the right strip and a voltage fluctuating between 255 and 265 on the two + pins for the left strip, and 0v on the - pin" you + Voltage feeding the Anode of the LED string but no Voltage on the - which is the Cathode of the LED string because the LED string is not in place. The Voltage went up 255V DC which is normal because it does not see the load.
                        You need to connect the LED connector back in place then leave the black meter probe on the chassis, red probe on L- PIN 10 then turn on the TV to see what you get. Do the same on the + pin too.
                        Never stop learning
                        Basic LCD TV and Monitor troubleshooting guides.
                        http://www.badcaps.net/forum/showthr...956#post305956

                        Voltage Regulator (LDO) testing:
                        http://www.badcaps.net/forum/showthr...999#post300999

                        Inverter testing using old CFL:
                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                        http://s807.photobucket.com/user/budm/library/

                        TV Factory reset codes listing:
                        http://www.badcaps.net/forum/showthread.php?t=24809

                        Comment


                          #13
                          Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                          will do. but i did take those measurements with both the LED strings connected and not...
                          in the meantime here's the cold side voltages im getting.
                          wherever you see ~ means its fluctuating between those 2 values.
                          wherever u see OL, i had my meter set on 600VDC range...
                          Attached Files
                          Last edited by triplefour; 03-14-2018, 03:56 PM.
                          Don't fear the repair...

                          Comment


                            #14
                            Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                            ok i repeated my measurements and did like you said, checking each pin for what it does right when you plug in the tv, and none of the measurements change. still getting all zeroes except the fluctuating 248-260v on the right string (which when you're looking at the tv, is the left string)
                            Don't fear the repair...

                            Comment


                              #15
                              Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                              pretty sure what i have here is the connector not making good contact anymore. i think my LED testing tool damages the connector if im not careful how im using it (widens the hole inside the harness?), or the connectors are just made to barely touch the pins so that as soon as either side gets a little oxidized, there is a poor connection. i tried cleaning with alcohol but it does nothing. ive got a bottle of deoxit on the way (heard good things) but in the meantime i might have to apply the manual fix by adding short bits of copper into each hole of the connector so it actually makes contact when plugged in
                              Don't fear the repair...

                              Comment


                                #16
                                Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                                Poke your tool in from the back, never the front, as you've found out it can make the hole bigger.
                                You can use something like a pin to move the retaining leg and then it can be pulled out. Gently close it up with some pliers/tweezers and push it back in.

                                Comment


                                  #17
                                  Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                                  yes i will try that first, thanks
                                  Don't fear the repair...

                                  Comment


                                    #18
                                    Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                                    thank you diif for the common sense solution. with the LED strings now properly making connection, my PSU is performing as it should. the tv comes back on again and looks great. i used a vice grip to hold the part of the screen that if it flexes, half the string will go out, so it doesnt flex anymore, and all LED's are on and running stable.
                                    now the test: will it run for hours and hours and then eventually go into the power cycling? or was that somehow due to a faulty LED strip?
                                    somehow i doubt a faulty LED strip could be the culprit, since why would it run for hours first and then start cycling? if it was truly a bad LED strip i would expect to see it do a 2seconds to black kinda thing and then cycle.
                                    is this correct thinking?
                                    Don't fear the repair...

                                    Comment


                                      #19
                                      Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                                      Run the TV at lower backlights setting to to see if it will run even longer.
                                      Never stop learning
                                      Basic LCD TV and Monitor troubleshooting guides.
                                      http://www.badcaps.net/forum/showthr...956#post305956

                                      Voltage Regulator (LDO) testing:
                                      http://www.badcaps.net/forum/showthr...999#post300999

                                      Inverter testing using old CFL:
                                      http://www.badcaps.net/forum/showthr...er+testing+cfl

                                      Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                      http://s807.photobucket.com/user/budm/library/

                                      TV Factory reset codes listing:
                                      http://www.badcaps.net/forum/showthread.php?t=24809

                                      Comment


                                        #20
                                        Re: Samsung UN46ES6150F starts power cycling after 2 hours of use from a cold start

                                        i will definitely try that if it starts power cycling again. will let you know. thanks again!
                                        by the way, do you use suction cups to lift the LCD screen? ive been just using my hands but its pretty sketchy and i'd rather not be touching the mirror'd side of the LCD screen if possible. can you recommend a place to buy the correct "heavy duty" and large enough suction cups to lift up to a 60" screen?
                                        Last edited by triplefour; 03-15-2018, 10:22 PM.
                                        Don't fear the repair...

                                        Comment

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