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    Dell 2007wfpb power on problem

    Hello all and thanks for this forum, clearly allot of useful information on here.

    SO i have a Dell 2007wfpb which works intermittently but less and less lately. I have considered just binning it and buying a new monitor for 100 bucks but i don't like wasting things so here i am.

    What is happening is that when the monitor has been off for a long time, unplugged you can turn it on and get the dell logo to come up. if you leave it plugged in and then try to turn it on it goes into this loop of the green LED lights for power and source (1only) flash on then off with about 5-8 seconds in between and you here a relay clicking. it never comes out of this loop and never powers on. I have pulled it apart and looked at the different boards and there is no obvious signs of damage or bulged or leaking capacitors. I checked the fuse on the power board and somewhat checked the capacitors on that board with a multi meter and they all start to take a charge. I have attached the photos i have of the power board. Any suggestions are appreciated.
    Attached Files

    #2
    Re: Dell 2007wfpb power on problem

    Do the inverter tests mentioned in this post
    https://www.badcaps.net/forum/showth...light=2007wfpb
    Please upload pictures using attachment function when ask for help on the repair
    http://www.badcaps.net/forum/showthread.php?t=39740

    Comment


      #3
      Re: Dell 2007wfpb power on problem

      Thanks for the reply! so i checked the resistance on the

      T801
      S1-S2 = 1076
      S3-S4 = 1066

      T802
      S1-S2 = 1070
      S3-S4 = 1062

      T803
      S1-S2 = 1073
      S3-S4 = 1068

      I am not sure how to check the mosfet

      Comment


        #4
        Re: Dell 2007wfpb power on problem

        Transformer readings look ok. Check mosfet using this guide, start at post #13, step 2:

        https://www.badcaps.net/forum/showthread.php?t=10419

        A photo of the entire inverter board would be nice.
        Last edited by jetadm123; 01-16-2013, 05:06 PM.

        Comment


          #5
          Re: Dell 2007wfpb power on problem

          About to try and check these mosfets, but here is some pictures.
          Attached Files

          Comment


            #6
            Re: Dell 2007wfpb power on problem

            I think I misread your first post.
            Are you saying if the monitor is unplugged for a while then set up it works? is it connected to a pc?

            But then if you leave it plugged in but switch it off then back on it does does not come on.

            I read it that you had a single flash of the backlights but now wonder if you mean only the power led flashes on then off then on every 8 seconds or so
            Please upload pictures using attachment function when ask for help on the repair
            http://www.badcaps.net/forum/showthread.php?t=39740

            Comment


              #7
              Re: Dell 2007wfpb power on problem

              yes so, if its is unplugged from the wall for a period of time it seems to come on and you get the dell logo as it boots up and works normal if connected to a PC. But after the PC puts it to sleep it wont come out of sleep it just flashes the LED as if its trying to power on and you hear the relay clicking. Same thing if it is unplugged from a PC source and just plugged into the wall socket. its like it gets warm and stops working but works when its cold.

              Comment


                #8
                Re: Dell 2007wfpb power on problem

                If it was mine, I'd replace ALL the crap caps on the power supply (except the large one)
                Those are CRAP caps, and just 'cause they're not bulging doesn't mean they aren't causing problems.
                36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

                Comment


                  #9
                  Re: Dell 2007wfpb power on problem

                  ok so i did that, replaced all the caps on the power board except the large one. Re assembled and its doing the same thing except this time it didn't give me any thing on the screen just the Power LED and source 2 flashes at about a 5 second interval.

                  Thanks for all the ideas to try guys, i would say i'm an intelligent beginner so all the help is greatly appreciated.

                  any more ideas ?

                  Comment


                    #10
                    Re: Dell 2007wfpb power on problem

                    OK, let's think this through a bit.

                    Are there voltages marked on the connector on the power supply?
                    If so, lets measure them each one referenced to ground. So meter on DCV whatever range is higher than the highest marked voltage, red on the voltage we're measuring, black on gnd.
                    36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

                    Comment


                      #11
                      Re: Dell 2007wfpb power on problem

                      Check that you have put the caps in the right way round - what make did you use?
                      Please upload pictures using attachment function when ask for help on the repair
                      http://www.badcaps.net/forum/showthread.php?t=39740

                      Comment


                        #12
                        Re: Dell 2007wfpb power on problem

                        "Are there voltages marked on the connector on the power supply?"

                        so you mean the 250Volt marked in the attached picture by the fuse?

                        "If so, lets measure them each one referenced to ground. So meter on DCV whatever range is higher than the highest marked voltage, red on the voltage we're measuring, black on gnd."

                        red on the fuse ?

                        Check that you have put the caps in the right way round - what make did you use? Caps are on correctly G-Luxon is he make
                        Attached Files

                        Comment


                          #13
                          Re: Dell 2007wfpb power on problem

                          No, on the connector that has the multi coloured wires that go to another board.
                          Looking for markings like 5v 12v etc.
                          36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

                          Comment


                            #14
                            Re: Dell 2007wfpb power on problem

                            Didnt notice before as I was looking for a white smd, there is a yellow torpedo fuse on the inverter board pic 2 - meter on ohms - test and post the result.
                            Please upload pictures using attachment function when ask for help on the repair
                            http://www.badcaps.net/forum/showthread.php?t=39740

                            Comment


                              #15
                              Re: Dell 2007wfpb power on problem

                              I get 18.9 volts on orange yellow green and zero on the rest. if attached a photo but i see no voltages on the front or the back of the board.

                              The yellow torpedo fuse is good according to the meter reading 1.

                              Thanks again for the help.
                              Attached Files

                              Comment


                                #16
                                Re: Dell 2007wfpb power on problem

                                Originally posted by red23 View Post
                                I get 18.9 volts on orange yellow green and zero on the rest. if attached a photo but i see no voltages on the front or the back of the board.

                                The yellow torpedo fuse is good according to the meter reading 1.

                                Thanks again for the help.

                                I think1. may mean out of range - open - is that the same as it reads when the probes are not touching anything?
                                Please upload pictures using attachment function when ask for help on the repair
                                http://www.badcaps.net/forum/showthread.php?t=39740

                                Comment


                                  #17
                                  Re: Dell 2007wfpb power on problem

                                  your right, its 1 when they aren't touching anything and zero when you touch them together, i put them on the fuse and it reads zero.

                                  Comment


                                    #18
                                    Re: Dell 2007wfpb power on problem

                                    Ok So the ohms test on the fuse is the same as holding the probes together.
                                    Yes?

                                    Next then with the boards powered and connected set your meter on 200vDC
                                    put the black probe on a ground screw or metal casing of a connector and with the red probe check the voltage on each side of the fuse.
                                    Please upload pictures using attachment function when ask for help on the repair
                                    http://www.badcaps.net/forum/showthread.php?t=39740

                                    Comment


                                      #19
                                      Re: Dell 2007wfpb power on problem

                                      "Ok So the ohms test on the fuse is the same as holding the probes together.
                                      Yes?"

                                      Yes

                                      zero voltage on either side of the fuse after it is plugged in. now i just plugged in those 2 boards if that makes difference, i don't have all the boards out of the metal case but i could do if that's what is needed.

                                      Comment


                                        #20
                                        Re: Dell 2007wfpb power on problem

                                        I did some searching on other threads about this model, and according to most of the photos, there aren't any voltages marked on the connectors.
                                        When you measured the voltages on the connector, was the other end plugged in to another board?

                                        I did read where a couple of these monitors (one was Retiredcaps) had shorted voltage regulators on the main board. Might not be a bad idea to test those.
                                        How about a good photo of the main pcb and we can help you test them.
                                        36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

                                        Comment

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