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    Samsung 213T inverter

    I am working on a couple of Samsung 213T 21" lcd panels. They do not power on. I started by recapping the psu with 6 caps that I had on hand (top 3 are NHG 1000uf 25v - {i know this is bad - FCs are on the way}). Still the power will not come on. I noted that the power supply was making a clicking sound. I probed the voltages coming out of the PSU and they were fluctuating. So I concluded that the power supply was cycling.

    Exploring this idea, I unplugged the inverter board and lo and behold the clicking went away. I was then able to get a green power light to come on when I pushed the power button. I tried shining a flashlight to see if there was an image, but none was apparent.

    Now I am concentrating on the inverter. I tried testing the 4 220uf caps with my cap analyzer 88a, but it showed a short. I removed the 4 caps and tried testing them out of circuit. Apparently they are completely gone because the cap analyzer doesn't recognize them. The look like they could be domed, but the glue on top makes it hard to tell.

    The inverter board still shows a short between the holes for all of the caps and across the primaries of the transformer coils and pretty much the whole inverter board. I assume that this is not good. The secondaries of the transformers read 219 ohms.

    Can anyone make any recommendations on what to do next? I have some new caps on order. Should I just put them in and fire it up? Or is there something else I should look at? Like lifting one side of the transformers to check them for shorts out of circuit (this is scary because everything but the 4 e-caps are SMD)? It is hard to tell, but there is some goo on each side near the blue caps and big resistors. It doesn't look it is coming from the transformers, looks more like it came from the white glue stuff.
    Attached Files
    Last edited by bluto; 02-22-2010, 07:54 PM.

    #2
    Re: Samsung 213T inverter

    Well I guess I need to correct my post a little. I read some of the other posts on measuring the resistance across the primaries on some of these transformers. It looks like low resistance is the norm here. So when I said that they were shorted (ie my continuity beeper went off), I actually mean that I get 2.1 ohms across the primaries and 2.6 ohms across the capacitor pads.

    Comment


      #3
      Re: Samsung 213T inverter

      Originally posted by bluto
      I am working on a couple of Samsung 213T 21" lcd panels. They do not power on. I started by recapping the psu with 6 caps that I had on hand (top 3 are NHG 1000uf 25v - {i know this is bad - FCs are on the way}). Still the power will not come on. I noted that the power supply was making a clicking sound. I probed the voltages coming out of the PSU and they were fluctuating. So I concluded that the power supply was cycling.

      Exploring this idea, I unplugged the inverter board and lo and behold the clicking went away. I was then able to get a green power light to come on when I pushed the power button. I tried shining a flashlight to see if there was an image, but none was apparent.

      Now I am concentrating on the inverter. I tried testing the 4 220uf caps with my cap analyzer 88a, but it showed a short. I removed the 4 caps and tried testing them out of circuit. Apparently they are completely gone because the cap analyzer doesn't recognize them. The look like they could be domed, but the glue on top makes it hard to tell.

      The inverter board still shows a short between the holes for all of the caps and across the primaries of the transformer coils and pretty much the whole inverter board. I assume that this is not good. The secondaries of the transformers read 219 ohms.

      Can anyone make any recommendations on what to do next? I have some new caps on order. Should I just put them in and fire it up? Or is there something else I should look at? Like lifting one side of the transformers to check them for shorts out of circuit (this is scary because everything but the 4 e-caps are SMD)? It is hard to tell, but there is some goo on each side near the blue caps and big resistors. It doesn't look it is coming from the transformers, looks more like it came from the white glue stuff.
      Second picture, there are 4 'ICs' (probably FETs) in each of two columns. It appears that the 'magic smoke' has escaped from the bottom two ICs in the left column. What are the part numbers on these?

      PlainBill
      For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

      Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

      Comment


        #4
        Re: Samsung 213T inverter

        Wow you have a good eye! On further inspection, they do look burnt. There is discoloration on the bottom of the board in that exact spot. So it looks like they got hot. The part number is (@?) 4600 BE4T1B. Guess I am going to have to learn how to surface solder.

        Comment


          #5
          Re: Samsung 213T inverter

          Originally posted by bluto
          Wow you have a good eye! On further inspection, they do look burnt. There is discoloration on the bottom of the board in that exact spot. So it looks like they got hot. The part number is (@?) 4600 BE4T1B. Guess I am going to have to learn how to surface solder.
          Those parts may all be identical, or there might be two complementary part numbers.

          As for removing SMT components, a product called Chip Quik is excellent. It has reached the point where I would rather work with SMT components than through hole.

          PlainBill
          For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

          Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

          Comment


            #6
            Re: Samsung 213T inverter

            Ok it looks like that is an AO4600. And according to their site it is discontinued.

            http://www.aosmd.com/web/products/pr...tree&tree_id=9

            Possible replacements are listed as AO4619 and AO4622

            Digikey has both. How do if figure out which one I need? The 4619 has 30v drain to source vs. the 4622 which has 20v. Otherwise they seem very similar. Looks like Digikey has Chip Quik also.

            Comment


              #7
              Re: Samsung 213T inverter

              Originally posted by bluto
              Ok it looks like that is an AO4600. And according to their site it is discontinued.

              http://www.aosmd.com/web/products/pr...tree&tree_id=9

              Possible replacements are listed as AO4619 and AO4622

              Digikey has both. How do if figure out which one I need? The 4619 has 30v drain to source vs. the 4622 which has 20v. Otherwise they seem very similar. Looks like Digikey has Chip Quik also.
              AO4600 are still about
              Plenty on Ebay
              This link may help
              http://cgi.ebay.co.uk/Lot-of-Two-2-A...item3350ad0589

              Comment


                #8
                Re: Samsung 213T inverter

                For a small job like this Chipquik is pretty expensive. For large pin count ICs it's the only way to go though.

                A simpler way for smaller packages like these is to get a sewing needle blob up the 4 pins with solder put the needle underneath the pins if it won't press under just leave it in place. Then melt the solder press the needle under and lift until the pins clear the solder. For the other side just blob up the pins and remove the IC with tweezers.

                Clean up the solder on the traces with desoldering braid and you're ready for reinstallation.

                I use this method on up to 6 pin packages anything larger I use Chipquik.

                I learned this from a guy when I used to replace Xbox HDDs since their EEPROM on the mobo was a 4 pin SMD package like this one. The ICs had to be removed intact since they contained the unlock code for the HDD.
                Last edited by Krankshaft; 02-23-2010, 08:18 AM.
                Elements of the past and the future combining to make something not quite as good as either.

                Comment


                  #9
                  Re: Samsung 213T inverter

                  I have had success repairing a couple of these inverters. I used AO4619 MOSFETS (http://search.digikey.com/scripts/Dk...=785-1044-1-ND) as replacements for the 4600's. Since I had several to do, I got some chipquik that worked very well getting the old ones off.

                  If you are fixing one of these, test for shorts between pins 2 to 3, 2 to 5-8, and 3 to 5-8 on all eight of the 4600 MOSFETs. Replace any that show a short. They seem to fail in pairs. You will also need to check the two SMD fuses and replace/jumper as necessary. Be sure to replace all the caps on the inverter and the power supply while you are at it.

                  Attached are a couple of pictures showing the replacement of the MOSFETS. Pins 5-8 are shorted by the board, so I went ahead and put a big blob of solder across them. They are a little crooked, but over all not bad for my first attempts at surface soldering. Do yourself a favor and replace the caps on the inverter after you have replaced the MOSFETS.

                  Thanks again to everyone who replied to this thread for their help.
                  Attached Files

                  Comment


                    #10
                    Re: Samsung 213T inverter

                    Originally posted by bluto View Post
                    Well I guess I need to correct my post a little. I read some of the other posts on measuring the resistance across the primaries on some of these transformers. It looks like low resistance is the norm here. So when I said that they were shorted (ie my continuity beeper went off), I actually mean that I get 2.1 ohms across the primaries and 2.6 ohms across the capacitor pads.
                    Hi bluto, I have replaced all the caps on the powerboard and inverter board and it still has the same problem. Green light and no screen. I see 2 suface fuses locations f51 and f101. They test open 17v dc in and 0v out. I guess these need replacing. Can you tell me if this sounds right and what with?

                    Thanks
                    Steve

                    Comment


                      #11
                      Re: Samsung 213T inverter

                      smamado,

                      The fuse blew because of one of the mosfets (one of the 8 'eight pin' SMD chips on the board) shorted. The mosfet failed because of the bad caps on the inverter board. See my picture as marked up. You will need to determine which mosfet shorted and replace it. Once you are sure the short has been fixed, you can replace or jumper the fuse. Since you say that both of your fuses are open, then you have shorted mosfets on both sides of the board. In my example only one side had a short.
                      Attached Files
                      Last edited by bluto; 07-24-2011, 05:57 PM.

                      Comment


                        #12
                        Re: Samsung 213T inverter

                        Hi,

                        Thanks to this thread I have just fixed my 213T. On the beginning I replaced all six caps on the PSU and all four caps on the inverter board. Panel started to work but the upper part of LCD was much darker then lower. I checked mos-fets and and two of them was failed also. I replaced them and the fuse which protect them also and... panel has been recovered!

                        Thanks,

                        jaceksto

                        Comment


                          #13
                          Re: Samsung 213T inverter

                          I'm having an issue with one of my 213ts.

                          Originally it had a fast blinking green light. I replaced the 6 PS caps (All were domed) and I replaced the 4 on the inverter board.

                          The problem then changed. There is still no display at all and now no green light. Since I happen to have 2 of these monitors (One still being good), I narrowed it down to the inverter board being bad. Any ideas?

                          I already checked for ring cracks at the power socket and I can't find a diagram of which parts are which for the inverter. In fact I can't find anything on the net for the interver board.

                          Comment


                            #14
                            Re: Samsung 213T inverter

                            Originally posted by Cybs View Post
                            I'm having an issue with one of my 213ts.

                            Originally it had a fast blinking green light. I replaced the 6 PS caps (All were domed) and I replaced the 4 on the inverter board.

                            The problem then changed. There is still no display at all and now no green light. Since I happen to have 2 of these monitors (One still being good), I narrowed it down to the inverter board being bad. Any ideas?

                            I already checked for ring cracks at the power socket and I can't find a diagram of which parts are which for the inverter. In fact I can't find anything on the net for the interver board.
                            Suggest the following:

                            1) check polarity of the caps you installed to make sure none were installed backwards.

                            2) check for any solder bridges that may be causing a short.

                            3) reseat the wiring harnesses between the power/signal/inverter boards.

                            4) if you used RadioShack caps or any other non low-esr caps, then that could be a possible source of your problem.

                            Comment


                              #15
                              Re: Samsung 213T inverter

                              Originally posted by Cybs View Post
                              I'm having an issue with one of my 213ts.

                              Originally it had a fast blinking green light. I replaced the 6 PS caps (All were domed) and I replaced the 4 on the inverter board.

                              The problem then changed. There is still no display at all and now no green light. Since I happen to have 2 of these monitors (One still being good), I narrowed it down to the inverter board being bad. Any ideas?

                              I already checked for ring cracks at the power socket and I can't find a diagram of which parts are which for the inverter. In fact I can't find anything on the net for the interver board.
                              The easiest way is to post high resolution pictures of your inverter using 'Manage Attachments' - below the text entry area. I'd suspect something like a solder short.

                              PlainBill
                              For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

                              Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

                              Comment


                                #16
                                Re: Samsung 213T inverter

                                Originally posted by jetadm123 View Post
                                Suggest the following:
                                4) if you used RadioShack caps or any other non low-esr caps, then that could be a possible source of your problem.
                                I was afraid you were going to say that. Those 4 caps were the only ones I bought locally and they were the only ones I could find.

                                Comment


                                  #17
                                  Re: Samsung 213T inverter

                                  Originally posted by PlainBill View Post
                                  The easiest way is to post high resolution pictures of your inverter using 'Manage Attachments' - below the text entry area. I'd suspect something like a solder short.

                                  PlainBill
                                  Hopefully this is hi res enough for you.

                                  I just checked voltage at the ceramic fuse on the PS board and on both sides the voltage is flickering between 2.5v to 2.8v. I am going to assume that is a problem?
                                  Attached Files
                                  Last edited by Cybs; 12-15-2011, 01:29 PM.

                                  Comment


                                    #18
                                    Re: Samsung 213T inverter

                                    Read thru the thread again. You almost certanly have a shorted mosfet on your inverter. Use my procedure to determine which one. You might also check between. the two leads of the inverter caps for a short (this will tell you what side of the board the shorted mosfet is on). I did over 30 of these and almost every one had a shorted mosfet as a result of the bad caps.

                                    Comment


                                      #19
                                      Re: Samsung 213T inverter

                                      Originally posted by bluto View Post
                                      Read thru the thread again. You almost certanly have a shorted mosfet on your inverter. Use my procedure to determine which one. You might also check between. the two leads of the inverter caps for a short (this will tell you what side of the board the shorted mosfet is on). I did over 30 of these and almost every one had a shorted mosfet as a result of the bad caps.
                                      You are correct. I have the chips on order and they should be here in 6 days. I had to use eBay since it looks like Digikey doesn't carry them anymore or at least the link shows 0 qty.

                                      Comment


                                        #20
                                        Re: Samsung 213T inverter

                                        Yea it appears the they are non stocking now at DigiKey. Minimum order is 3000 pieces.... I do have a few spares if anyone needs some.

                                        Comment

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