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    Samsung UN55ES550F Tcon Fuses

    Let me take a moment to thank you all for your help on past issues.

    I have no verifiable history on this TV. I'm near/in Houston so anything a few years old has seen plenty of opportunity for wet.

    There are no telltale signs of any moisture at this point.

    The TV has standby light and one quiet click at power on attempt and Samsung logo glows blue.

    Panel stays black, w/o backlight.
    ____

    A T-shoot as opposed to checking the record for similar faults, is newish to me but here goes:

    The big caps on PSB are behaving themselves. 160 volts and change in standby, 380+ volts at power on. Takes plenty of time to drop back as the panel is switched off and main power cord disconnected.

    The PSB > Main board cable is 20 pin. I can get to the odd stack simply enough and B5v and B13v are right there. A bit over on the 5V and just a bit under 13. (I know there are routinely suggestions to supply all voltages, my assumption was to disconnect at the Main and probe the female connector the for the even stack. And then I didn't.)

    In any event, my search fu was suggesting this was going to be Tcon or worse, so I headed south.

    I disconnected the (I assume) LVDS cable from the Tcon. In that configuration, on power up attempt I HAVE my backlights.

    More reading and I locate and test F100 to see it's served it's purpose. The original 125V, 5A is blown.

    Yes, testing the north/power side shows the 12.8 supply volts.

    I made it to the big city in time to grab some SMD fuses for the weekend. I couldn't get the 5A in the existing form factor, but the wee cylinders fit fine. I did grab some rectangular white ones but they were 2.5A.

    (Just hedging my bets. I hoped they could at least help in proof of concept, if everything continued to pear shape.)
    _____

    So unfortunately, the newly soldered fuse must have blown instantaneously, on it's only power up. Yes I had the ribbons exiting the Tcon connected.

    Rather than try running the Tcon with another fresh fuse, but with ribbons disconnected I decided to try and see if I could find a Tcon board problem. I am delaying pulling the black tape and fussing with what is beyond the bit of ribbon I can see.

    This is where my info searches diminish, and all help
    would be very much appreciated.

    I don't have a variable DC PS. (The stuff I have is 12v or better, and plenty of current, but...)

    I don't know much of anything about circuit/board design, so I just look at all of it. (And Hope.)

    I have attempted to look for Tcon SMD cap shorts to ground. I did most of the top side. Just about all acted as I hoped with ONLY the ground plane side beeping continuity at about 1 ohm.

    Then I realized, I was ignoring some things that looked like tantalum caps. They are a CD prefix rather than C, and I apparently can't find that definition either.

    Both CD12 and CD13, marked 33-1E20 have continuity to ground on both ends. They are about an inch and a half below the almost 13V IN fuse.

    I have no idea if that is their behavior.

    The Tcon board model is BN41-01790
    ____

    Naturally any ideas on improving my next steps are welcome. ( I don't even know who the usual suspects are? )
    Attached Files

    #2
    Re: Samsung UN55ES550F Tcon Fuses

    33µf/25v Conductive polymer chip tantalum capacitor, Either the cap is dhorted or something on that line is shorted

    When you say "have continuity to ground" I hope you are not basing that on the meter BEEPING
    Last edited by R_J; 09-21-2019, 01:36 PM.

    Comment


      #3
      Re: Samsung UN55ES550F Tcon Fuses

      If you don't have backlights, the first step is to unplug the cable from the main board from the ps. Backlights should come on because of internal pullups. If they don't you have bad backlights (most likely) or bad ps (bad backlights on Samsungs can damage the ps). You may have multiple issues.

      Comment


        #4
        Re: Samsung UN55ES550F Tcon Fuses

        Okie Dokie

        I finally managed to get enough light for a better resolution photo of this area.

        (The third shade of green is shadow from the taller components.)

        I did some more continuity testing, then decided to pop off CD12 and CD13 since my testing didn't mean much to me.

        All four pads for CD12 and CD13 are going to ground, now. The caps are not showing continuity at room temperature.

        So, what I have seen heading down from there. The 2 pak of cap over resistors: CD11 and RD05 each have one leg to ground and the other side is open.

        CD10 and RD04 are all open relative to ground. Looks like a series run.

        DD1, a two legged diode I guess, is grounded on the top pad in the image and open on the other side, LD1 is reading open on both ends, and that looks like it could be series too?

        The IC that I think the QD1 label is for, I figured the board triangle, and the IC dot was pin 1, so I thought I'd see ground at the opposite corner, which I thought should be 6. That's not the case. No beeps on QD1 at those pins.

        The last bit I probed was LD3. Each side gave me a beep at 213 ohms or so.

        (I kinda hope that's bad.)
        Attached Files

        Comment


          #5
          Re: Samsung UN55ES550F Tcon Fuses

          R J,
          Since all I have is the DMM, I'm just moving the red pin from each component/pad , while the black stays on the copper chassis screw hole.


          All except the LD3 are at one ohm or less, when I'm suggesting continuity to ground.

          Comment


            #6
            Re: Samsung UN55ES550F Tcon Fuses

            QD1 is a mosfet, pins 1,2,5,6 are the drain, 4 is the source and 3 is the gate, none will be ground, It could be the boost regulator that boosts the HVIN_12V via LD1 (coil) and DD1 (diode) to get the AVDD_17.3V
            I suspect the short will be on that 17.3v line somewhere
            Check if those caps (CD13&CD12+) connect to RD03, and ICD1 pin19, the ic could be shorted?

            I asked about the continuity testing because some people here the meter beep and assume a short, but most meters with the continuity/beep will beep between 0 and 150Ω
            Last edited by R_J; 09-21-2019, 11:28 PM.

            Comment


              #7
              Re: Samsung UN55ES550F Tcon Fuses

              Well Mr R J, first you made me grin, then you got a... “you gotta be kidding me'. First thing this morning. Nicely done.

              I had never used the beeper. Two reasons, I probably never realized it was beeping, and didn't know the function existed on the unit. (The sound is probably very near my drop... very near one of several drop offs.)

              The reason I mentioned it, in the thread... is because I saw it here as well.

              (I'm constantly glancing and re-positioning probe pins, on my victims, to have faith in what I'm seeing.)
              _____

              RD03 is where I made it to, trying to run that trace, last night. I looked at that little booger and said to myself... “I hope not”... , since I promised myself not to try and interpret resistors or diodes anyway.

              I didn't understand what the probes were telling me, and turned around and pulled the tantalums off.
              _____

              Yes... they are all singing the blues this morning.

              Both sides of RD03 and then Pin 19 on the 40 legged spider, are all communicating, as my medical friends say, with each and every one of the four, still blank, pads associated with CD12 and CD13.

              Two of the pads to Pin 19 are .1 or .2 ohm and probably dropping. Two may have stopped at .4 ohms.

              Does this mean I get to revert to my 'DMM only' inspired diagnostic method and attempt to float ICD1 off of there and see if the short stops? As with the tantalum pair?
              ______

              Backstory: I received a new to me, in nice physical shape, rework station just last week. It only had one ~9mm nozzle. (The connector next to the fuse, in this thread above, is now singed, for example.)

              The rework station suffered from rough handling, the missing shipping screw and the inclement weather. (Apparently we are now using convertible delivery trucks, with the top down, in the rain, to deliver electronics.)

              Yesterday, the amazonians dropped off a set of smaller nozzles, so the tantalums were the first to receive a more narrow air flow test. ( This is still real close to my first rodeo.)
              Last edited by Renovator; 09-22-2019, 10:13 AM.

              Comment


                #8
                Re: Samsung UN55ES550F Tcon Fuses

                Between CD12/13 and the ic's pin 19 is RD03, That should be quite easy to remove and see which side of RD03 has the short.

                Comment


                  #9
                  Re: Samsung UN55ES550F Tcon Fuses

                  Well... the little, I mean pretty little... guy took more time and flux than I would have thought.

                  It's off and the short stops at the CD12/13 side of the resistor.

                  ____

                  The higher rez pix may be of help in the future.

                  I doubt I'm going to be seeing that resistor again. It was on the end of my tweezie. And I rolled them to free it. I heard a click, and apparently I was in trebuchet mode...

                  With it's mass, it can't have gone far...

                  ____

                  Had a thought, midpost:

                  Back side of Tcon.


                  That pic isn't so good, but southeast from the northwest chassis hole is a lone ranger CD14 (… really) .


                  It looks to be straight under DD1 on the topside.

                  I'm reading .1 > .2 on the east pad (relative to the pic.) And 1.0 > .9 on the west side.

                  (I'll upgrade that photo.)

                  Comment


                    #10
                    Re: Samsung UN55ES550F Tcon Fuses

                    RD06 is showing short. (I was only looking at caps at that point yesterday, and just passed it by.)

                    RD08 seems fine only one side to ground. On to PIN 29: was pleasantly uneventful.
                    Attached Files

                    Comment


                      #11
                      Re: Samsung UN55ES550F Tcon Fuses

                      I believe RD06 is (01d) is 100kΩ. It likely goes from CD13+ to ground thats why it checks shorted.
                      It looks like RD03 is the same as RD25 and Rd10 and others so maybe they have the same value, they could be low ohm resistors 0~10Ω
                      most of the other resistors have marked values
                      If you had a bench power supply you could try applying a few volts across CD13 or CD12 and see what component gets hot, even 3 or 4 volts or a 1.5v battery would be safe in ths area. it would be easier than trying to remove smd parts
                      Just connect the - to ground and touch the + to the + side of the cap for a couple seconds at a time.
                      Last edited by R_J; 09-22-2019, 05:39 PM.

                      Comment


                        #12
                        Re: Samsung UN55ES550F Tcon Fuses

                        That trace from RD06 runs to the far side of the place a CD06 could go. That one tab is ground. Seems consistent.

                        As is pin 4 of IC700.


                        Take your pick and I'll heat something up.

                        Sounds like CD14 needs to be looked at.
                        Last edited by Renovator; 09-22-2019, 05:35 PM.

                        Comment


                          #13
                          Re: Samsung UN55ES550F Tcon Fuses

                          Just a status update:

                          (I missed the edit at first.) I'm hoping I'm in a 'more power' sit.


                          I took some 1.5 volt cells that were testing good. On a 1.5V that's said to be 4mA.


                          For late night giggles I strung two AA in series for 3V at milliamp current, and used a lone D cell in a subsequent effort at 1.5V.

                          My understanding is the various sized 1.5V cells have the same max current value, just more of it available. Size matters here.

                          Nothing. Repeatedly.

                          Don't worry, I had the Mr. Freeze can involved, as well as my calibrated fingertips, and I felt or saw no change in state or temp or anything else.

                          With cold frosting applied or not. Front and back of board,

                          The old saw about the wide traces being left, in production, for heat dissipation may be working perfectly well at these levels. The little watts never concentrated anywhere.

                          I got lot's of lower volt output transformers. (If they haven't made it to the salvors.)

                          Rolling the dice, what rated current output might get me over this threshold I may be dealing with, but still seems like it could be safe if I'm fast enough.

                          (Understanding of course that the world sux, so current is pulled and not pushed.)

                          Recapping: I have found 3 caps that seem to test as short, in the same area.


                          They are CD12/13/14.


                          CD12 & CD13 have been removed and all 4 pads are talking to ground.


                          CD14 is still soldered to the board.


                          All three ground side pads show 0.1 ohm, and all + side show 0.9 ohm to ground.

                          _____

                          For a number of reasons I want to apply more juice to see if there is a hot spot... somewhere.

                          Looking ahead, is there a scenario, where a warm device doesn't show, even with a fault effecting the area near CD12/13/14 ?

                          Comment


                            #14
                            Re: Samsung UN55ES550F Tcon Fuses

                            Are you performing the test with the ribbon cables between T-CON and the LCD panel still connected?
                            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


                              #15
                              Re: Samsung UN55ES550F Tcon Fuses

                              X2... plus did you measure / check the capacitors that you removed to see if they respond OK?

                              "All three ground side pads show 0.1 ohm, and all + side show 0.9 ohm to ground."

                              that seems to suggest you don't have a short.... you have some form of "1ohm" resistor which may be valid depending on where in the circuit, it exists. further, when you are checking resistance, are you switching your leads around to check both "polarities" just in case there are active components which "react" to the "+" biasing.
                              Last edited by budwich; 09-23-2019, 10:30 AM.

                              Comment


                                #16
                                Re: Samsung UN55ES550F Tcon Fuses

                                budm,

                                No. The Tcon is off chassis.

                                I figured first play was to keep a fuse from blowing.

                                The original to me fuse and the first replacement, blew with all cables connected.

                                I started this thread without doing the lower ribbon to panel dance.

                                So I have NOT tried to see if the fuse would blow with the ribbons, or each ribbon one at a time connected.


                                (The weekend was coming and I had only so many fuses. Greedily if I could find a fault on the board then I wouldn't have to pull the lower surface panel, and whimper.)

                                _____

                                budwich,

                                The tantalums removed, were not shorted.

                                I did not switch leads. I will.
                                ____

                                I did.

                                There is no change in value, switching leads used on either side.

                                There is a slight but real, repeatable change in value empirically.

                                Today, 24 hours after the last check, the ground side is 0.0 ohms.

                                The other side of each component, including the spot for the resistor RD03, are now all 0.7 ohm.
                                ____

                                You're right, I was getting tunnel vision. The weekend is over and I can find a reason to get to where more parts are. I have a few fuses left, anyway.

                                So the corollary is also true. I won't do any damage probably, if I plug this board back in now, without the tab bound ribbons and turn it on?

                                If it quickly launches the fuse with three opens, and no lower ribbons, then the board still needs help.

                                Comment


                                  #17
                                  Re: Samsung UN55ES550F Tcon Fuses

                                  Can you check the resistance of the MLCC (Multi Layer Ceramic Cap) tan color SMD caps by the two connectors that go to the LCD panel?
                                  The AVDD is used for running the COF.
                                  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


                                    #18
                                    Re: Samsung UN55ES550F Tcon Fuses

                                    "So the corollary is also true. I won't do any damage probably, if I plug this board back in now, without the tab bound ribbons and turn it on?"

                                    I wouldn't do that quite yet as I think budm's test is a good test.... and you are still likely on the right track, that the problem is in the board and not the panel ... perhaps, assuming that the panel didn't take out one of the components on the tcon to begin with.... which might be the case ... ie. a double fault.

                                    Comment


                                      #19
                                      Re: Samsung UN55ES550F Tcon Fuses

                                      Thanx for that budwich.

                                      I grabbed this TV figuring it was past the known fix-it stuff, and I would be diving into a T-shoot.

                                      If memory serves, you guys were all helping in the only other thread that I could get a pull for this model on. So if we can clear a different fault, perfect.

                                      At the same time, looking at the physical build quality and some of the broader interweb searches. This may be a season specific, promotional build.
                                      _____

                                      To the budm query:

                                      Those guys. You're right I didn't think they were shorted, since they were not listed above. But there was something different about the original pass, compared to the others.


                                      This Morning, using Auto-Ranging seems to give the most consistent, repeatable results.


                                      The four larger form factor:
                                      CO45 0.7 Ohm
                                      CO46 0.7 Ohm
                                      CO47 0.7 Ohm
                                      C048 0.7 Ohm

                                      The smaller stuff:
                                      CO41 6.3 kOhm
                                      CO43 6.3 kOhm

                                      On the left ribbon side, (their labels may be off camera).
                                      CC34 0.7 Ohm
                                      CC31 0.7 Ohm


                                      (The meter is a Klein MM600.) (I've got plenty of lightweight, little red meters, to double check with, if things look goofy.)

                                      Comment


                                        #20
                                        Re: Samsung UN55ES550F Tcon Fuses

                                        I would remove those that show 0.7 Ohms one by one and see if the low Ohms readings will go away. You should be able to use 200 Ohms scale to look for low resistance readinsg in both direction.
                                        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

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