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Dell 2007FPB teardown

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    #41
    Re: Dell 2007FPB teardown

    I've replaced the mosfet with another 2SJ598 with no change. Tested all the 272 resistors and they seem to be very well in spec.

    ADD// Eh, guys, did these displays came in pairs? I opened the other one and everything is mirrored in there. What was right is left and vice versa. The USB board has all four channels with four DC-DC modules.
    Last edited by Behemot; 05-14-2015, 10:52 AM.
    Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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      #42
      Re: Dell 2007FPB teardown

      So the DTC for the +12V part of the TL1451 is at 2.44 V which means it is at 0 duty cycle. I think the problem is here.

      I have checked all the corresponding SMD resistors and tiny SMD transistors around other TL1451s and all of the values are the same. So it seems those are OK. That really leaves me with bad TL1451 only?

      Replaced TL1451 from scrapped display, no change! Bloody hell this PoS.
      Last edited by Behemot; 05-14-2015, 12:46 PM.
      Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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        #43
        Re: Dell 2007FPB teardown

        Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

        Exclusive caps, meters and more!
        Hardware Insights - power supply reviews and more!

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          #44
          Re: Dell 2007FPB teardown

          I just did the most grimy 2.7k fix, I should have taken pictures.

          Used an enormous leaded resistor lol

          Works perfect now

          Comment


            #45
            Re: Dell 2007FPB teardown

            Still have not found anything. All the resistors check fine and have same value as resistors in the same position of the second PWM controller which works fine providing both +3.3 and +5 V. But the +12 V is jsut still not there. Something is making the PWM go into 0 % switching mode.
            Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

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              #46
              Re: Dell 2007FPB teardown

              Behemot, it sounds like you need to start a new thread. If you have some time, you could start a FAQ on troubleshooting lack of one rail when the others are working.

              Comment


                #47
                Re: Dell 2007FPB teardown

                Loud crackle and smoke today. Serious scorch marks on the board by the outlet (see pics), but I don't see any other visual signs or bad caps. Anyone have any insight into which parts may be the culprit?
                Attached Files

                Comment


                  #48
                  Re: Dell 2007FPB teardown

                  You had bad solder joints on the AC inlet to the circuit board, clean off all the carbon deposit and resolder all 3 pins and inspect the board for bad solder joints.
                  Common problem.
                  Attached Files
                  Last edited by budm; 01-29-2016, 05:08 PM.
                  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


                    #49
                    Re: Dell 2007FPB teardown

                    That's not safe to use any longer. I am afraid you will have to remove the inlet, clean as much as you can, drill out the burned stuff and solder IEC C14 cable in the two good positions and somewhere further on the single bad position (maybe on the fuse directly). Than somehow firm it in position so nobody tears it off.

                    Or you can cut piece of the board out and than place a new one in there with some epoxy, but that's too much of a work if you ask me and I am still not entirely sure it would be safe on full AC input voltage…
                    Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

                    Exclusive caps, meters and more!
                    Hardware Insights - power supply reviews and more!

                    Comment


                      #50
                      Re: Dell 2007FPB teardown

                      buy a new connector - and sand away all the carbon on the board.

                      Comment


                        #51
                        Re: Dell 2007FPB teardown

                        It's burned too close to the ground, replacing won't fix that. Besides, there is almost nothing left from the copper pad, where would you like to solder it??
                        Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

                        Exclusive caps, meters and more!
                        Hardware Insights - power supply reviews and more!

                        Comment


                          #52
                          Re: Dell 2007FPB teardown

                          Originally posted by Behemot View Post
                          It's burned too close to the ground, replacing won't fix that. Besides, there is almost nothing left from the copper pad, where would you like to solder it??
                          You're correct the solder pad is gone along with most of the outlet post.

                          Comment


                            #53
                            Re: Dell 2007FPB teardown

                            Thanks everyone for the advice. I found a new OEM power board on eBay for $25. Popped it in and my display is like new.

                            Comment


                              #54
                              Re: Dell 2007FPB teardown

                              Kinda expensive, new connector should cost like a buck and than it only needs some soldering and silicone tricks (or something similar)

                              BTW recently I've been disassembling the speakers I got which blew the +12 V rail. I think the reason is obvious…all caps were like 99 baloons. So next time before you connect those Dell speakers to your expensive display, always recap that thing first! You'll save yourself lot of troubles. And test them with external +12 V source lol
                              Last edited by Behemot; 02-09-2016, 04:14 PM.
                              Less jewellery, more gold into electrotech industry! Half of the computer problems is caused by bad contacts

                              Exclusive caps, meters and more!
                              Hardware Insights - power supply reviews and more!

                              Comment


                                #55
                                Re: Dell 2007FPB teardown

                                Might as well resolder those 3 post so it will not fail like the original one, the AC inlet is not well mounted and supported so plugging and unplugging the power cord at the inlet will weaken the joints seen too many of them failed.
                                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


                                  #56
                                  capacitors

                                  Budm, you made a post #129 abought samsung capacitors for ln52a550 tv the capcitors look the same but have different part numbers so witch one goes on top and witch one goes on the bottom I CHECKED AND ONE IS 35-OHM AND THE OUTHER IS 70-OHM ??thanks,john
                                  Last edited by johnz16; 02-09-2016, 09:32 PM.

                                  Comment


                                    #57
                                    Fixed another 2007 WFP

                                    Hey guys,

                                    i just fixed another 2007 WFP by replacing the 2,7 k resistor. Thx for the information. It was really hard to solder this little tiny resistor out and solder the new in... didnt really think it would work but it did.
                                    Attached Files

                                    Comment


                                      #58
                                      Re: Dell 2007FPB teardown

                                      Thank you all, Could not have done it without you
                                      Yesterday afternoon and half a night was well spent. Ordered power supply from eBay for my 2007FPb 1200x1600 monitor, but that was a $40 bust. That was not it. Combing internet and
                                      Finding Badcaps, measuring values on four boards components, I came across the defective resistor. Found 2.7K resistor in my parts supply and soldered it in. not the prettiest soldering job, but guess what it works.
                                      Cheers,
                                      Radek


                                      Comment


                                        #59
                                        Re: Dell 2007FPB teardown

                                        I just wanted to thank all involved for this post.

                                        I was after an old monitor to use on a CCTV system. Being a cheapskate (as I am), rather than buy one, I popped to my local waste & recycling centre and found one of these babies on the scrap pile. As it looked in good nick, I whipped it onto the van, but on getting it home found it wouldn't power up.

                                        I popped her open to check internal fuses and PSU caps all to no avail, then I came across this thread. Sure enough, that 2.7k resistor was open circuit, but I found a suitable candidate on a scrap PIR sensor.

                                        Seems funny that something so small should bring the whole thing to its knees. I assumed it would be a PSU fault and never imagined it would be a resistor hidden under a glob on the USB board.

                                        Still, I'm an electrican by trade, not an electrical engineer, so 230v cables and nuisance tripping RCD's are my cup of tea. I doff my hat to you chaps though; you really know your bananas!

                                        Cheers,
                                        David.

                                        Comment


                                          #60
                                          Re: Dell 2007FPB teardown

                                          I replaced the 272 resister but still now power button light. Has anyone found any other likely suspects for this monitor? Mine is the 2007wfpb. Thanks.

                                          Comment

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