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Dell 2407WFPb Monitor - Bad Cap

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    Re: Dell 2407WFPb Monitor - Bad Cap

    Originally posted by sabretooth View Post
    I checked F701. It seems OK! It's also not like any fuse I've ever seen before. But it checked out.
    No, as I said I had not seen one before but there was a phillips tv with some in a day or two back
    Unfortunately I've got no idea how to determine resistor wattage based on size. It's approx 4mm x 10mm, though. Googling "4x10mm resistor" has come up with a bunch of hits suggesting 1 watt.
    Ive looked on digikey - yes 1 watt is most likely

    The silver line of solder I think you're referring to - the goop that used to
    hold down the original capacitor? I'm not seeing any lines of solder.
    Good- couldnt tell from pic what it was - it was just something odd.
    Please upload pictures using attachment function when ask for help on the repair
    http://www.badcaps.net/forum/showthread.php?t=39740

    Comment


      Re: Dell 2407WFPb Monitor - Bad Cap

      Alrighty. I think I've got everything I need to know. Time to make the orders - having to turn to eBay for the resistors but everything else I can get from a few local reputable stores. Hopefully this ends with a working monitor and I can stop taking up a disproportionate amount of space in this thread!

      Comment


        Re: Dell 2407WFPb Monitor - Bad Cap

        Originally posted by sirzur View Post
        I have looked at it through a magnifying glass with a bright LED light on the surface and I can't see any dot I can only assume that pin 1 is the bottom left when the words are the right side up
        I must have bought the same component - no markings whatsoever as to what pin is supposed to be pin 1.

        Comment


          Re: Dell 2407WFPb Monitor - Bad Cap

          Originally posted by sirzur View Post
          I finally went by the bevel. Looked up the dimension of the SO-8 package and wikipedia showed the bevel. Pin 1 is on the bevel side, on the left
          Does yours have the bevel?
          Please upload pictures using attachment function when ask for help on the repair
          http://www.badcaps.net/forum/showthread.php?t=39740

          Comment


            Re: Dell 2407WFPb Monitor - Bad Cap

            I thought I was clever by doing a search on the forum and finding his post - shame I wasn't resourceful enough to find the followup It indeed does have a bevel on one side. Thanks.

            Comment


              Re: Dell 2407WFPb Monitor - Bad Cap

              Argh, well this has come to a premature end. When I was removing one of the ICs, I must have yanked out one of the lines onto which the IC solders. Damned if I can find where it comes from.

              Comment


                Re: Dell 2407WFPb Monitor - Bad Cap

                If you post a good picture of the damage zone we may be able to suggest
                a fix.
                Please upload pictures using attachment function when ask for help on the repair
                http://www.badcaps.net/forum/showthread.php?t=39740

                Comment


                  Re: Dell 2407WFPb Monitor - Bad Cap

                  Hopefully this is good enough, then!

                  I've already tried scratching around to find the trace but haven't tried very hard and didn't want to push it in deeper or make fixing more difficult.
                  Attached Files

                  Comment


                    Re: Dell 2407WFPb Monitor - Bad Cap

                    Looks fixable - I am just going off for a week (very inconvenient!) others should be able to advise. Try and clean the area up with isopropyl alcohol on cottonbud or soft brush
                    Probably Not all the pins need attachment see if you can find a datasheet for the chip.
                    Last edited by selldoor; 05-03-2012, 04:10 AM.
                    Please upload pictures using attachment function when ask for help on the repair
                    http://www.badcaps.net/forum/showthread.php?t=39740

                    Comment


                      Re: Dell 2407WFPb Monitor - Bad Cap

                      I agree with selldoor... Very inconvenient that he is having a week off!

                      Do you have any isopropyl alcohol? dont scratch it anymore just get hold of some of that stuff and it will clear the majority of it up. Then get us another pic and we can help work out what goes where.
                      Fixed so far : 1 Home cinema system, 16 LCD Monitors, 4 LCD TV's

                      How to resize your pictures guide click HERE
                      Retiredcaps Ideal post example click HERE

                      Comment


                        Re: Dell 2407WFPb Monitor - Bad Cap

                        Originally posted by WillyBobz View Post
                        Thank's for all the information NZROSSI, I have just looked on the website....wow it looks quite complicated! Can you give me any step by step instructions as to how to order, I will use the same agent that you used. Any help/advice GREATLY APPRECIATED!!!!
                        Regards
                        WillyBobz

                        Also need help.I smalltao point of view in things, but do not know how to do this?

                        Comment


                          Re: Dell 2407WFPb Monitor - Bad Cap

                          Alright, busy times but got some time to clean up the circuit board and take a photo.

                          I'm pretty sure I've ruined it! See attached.
                          Attached Files

                          Comment


                            Re: Dell 2407WFPb Monitor - Bad Cap

                            Hi Sabretooth,
                            Check out this link below, it is for a Polish forum, use google translate, it also has the Diagram for L651, hope that this may help you.
                            Good Luck!


                            http://obrazki.elektroda.pl/1950185900_1304529310.jpg

                            Comment


                              Re: Dell 2407WFPb Monitor - Bad Cap

                              Originally posted by WillyBobz View Post
                              Hi Sabretooth,
                              Check out this link below, it is for a Polish forum, use google translate, it also has the Diagram for L651, hope that this may help you.
                              Good Luck!


                              http://obrazki.elektroda.pl/1950185900_1304529310.jpg

                              I am not so sure-Willtbobz, what was the main link to this.
                              The components we do know are D605 on pin5 (not on pic) A 10k resistor on pin1 (could be on pic but not labelled C613 on pin 6 (not on pic)
                              Similarly we have R617 R627 R622 R609 Q602 not mentioned on pic.
                              perhaps they only have topside components labelled.
                              Please upload pictures using attachment function when ask for help on the repair
                              http://www.badcaps.net/forum/showthread.php?t=39740

                              Comment


                                Re: Dell 2407WFPb Monitor - Bad Cap

                                Right - Help required from circuit experts - I attach a pic - I have guessed that the IC in question is a NCP1200A (got confused in the threads) Most of the connections seem obvious but struggling with where pin 8 goes. Sabretooth can you see the hole/pin I have dotted the yellow to - what is on the other side of the board at that point. Can you do a close up of the area.
                                Team -feel free to comment this is a suggestion only and we dont want to cause further damage.
                                Attached Files
                                Please upload pictures using attachment function when ask for help on the repair
                                http://www.badcaps.net/forum/showthread.php?t=39740

                                Comment


                                  Re: Dell 2407WFPb Monitor - Bad Cap

                                  If I am correct, that HV pin is the kick start power input from the main DC supply through a bunch of resistors connected in series to drop the 325 Vdc from the main cap down to about 12~18vdc to start the SMPS, once it started, the power supply circuit inside the SMPS will switch from the HV pin to the VCC pin which is generated by the extra winding off the transformer.
                                  I have the 2407WFPB at home that I need to work on, so which board is this I need to look at?
                                  Last edited by budm; 05-20-2012, 02:28 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


                                    Re: Dell 2407WFPb Monitor - Bad Cap

                                    Power supply back – board number is 4H.L2K02.A01 position marked on attached
                                    Attached Files
                                    Please upload pictures using attachment function when ask for help on the repair
                                    http://www.badcaps.net/forum/showthread.php?t=39740

                                    Comment


                                      Re: Dell 2407WFPb Monitor - Bad Cap

                                      Originally posted by soumen1 View Post
                                      I have replaced the unknown zener with a 6.8V 5W zener. [...] My only remaining question is, should I continue like this with an external 5V power supply, or should I try to replace the hexfet and inductor back in the board. It would be nice to get back to one power supply. The danger is, if the gate control circuit was damaged, the zener and hexfet will do fireworks again, and this time I may not be lucky and downstream components may fry.
                                      Update: I tried replacing the hexfet, and thanks to the 5W 6.8V zener I earlier connected across the load, my display board (the one with the Genesis chip) did not fry. The hexfet gate control is clearly kaput as well, as the supposed 5V drain rose to about 7 volts and the zener got hot (but survived). I turned off the monitor hastily and returned to an external bypass 5V power supply to the display board.

                                      Without a schematic and test voltages, it's very hard to debug the gate control of the hexfet. So my plan is to install a Murata OKI-T/3-W40P-C POL buck DC/DC converter from the 19V source to the required 5V drain, bypassing the on-board converter completely like I am doing now, but drawing from the 19V rail on the internal SMPS board. BTW, I also added the 27V zener in parallel with a 30V MOV on the 19V rail (after the 5A slow blow fuse) for added safety in future.

                                      https://cdn.badcaps-static.com/pdfs/...4ea943619a.pdf

                                      Comment


                                        Re: Dell 2407WFPb Monitor - Bad Cap

                                        Originally posted by selldoor View Post
                                        Right - Help required from circuit experts - I attach a pic - I have guessed that the IC in question is a NCP1200A (got confused in the threads) Most of the connections seem obvious but struggling with where pin 8 goes. Sabretooth can you see the hole/pin I have dotted the yellow to - what is on the other side of the board at that point. Can you do a close up of the area.
                                        Team -feel free to comment this is a suggestion only and we dont want to cause further damage.

                                        Pin 8 connects to R603 on other side of board as in the Diagram on the link in my previous response.

                                        I have checked this against a power supply board that I have on the bench.
                                        Sorry unable to take a decent picture (close up)

                                        Comment


                                          Re: Dell 2407WFPb Monitor - Bad Cap

                                          Thats Great Willybobz - I forgot there is a high def pic earlier in the post.
                                          I think we just need sabretooth to test what pads he has got for continuity to the next joint then he can try and fit it. Any without continuity will have to be wired. Perhaps he can put a snipped cap leg into the "through" and a
                                          small wire from that to pin 8 rather than just a solder blob. Anyone any other ideas.
                                          Please upload pictures using attachment function when ask for help on the repair
                                          http://www.badcaps.net/forum/showthread.php?t=39740

                                          Comment

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