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    Re: Dell 2007WFP Won't Power On

    Originally posted by budm View Post
    I need to find the spec of the Schottky Diode, S4 64A to find out what the reverse voltage and current handling is.
    Never mind, found the answer from your old post:
    https://www.badcaps.net/forum/showthread.php?t=20059
    1A 40V, pretty low current.
    I don't have that diode part yet either. I'm hoping to find that in my junk pile of boards. Sellers on ebay are selling in quantities of 100.

    I have a backlog of projects and now that summer is on its way, the backlog won't get cleared anytime soon.
    Last edited by retiredcaps; 05-12-2012, 12:41 AM.
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      Re: Dell 2007WFP Won't Power On

      Thanks all. Can someone suggest some search terms so that I can identify some 2a replacement diodes on either eBay or Digikey? I'm thinking of getting an order together.

      Comment


        Re: Dell 2007WFP Won't Power On

        While getting my car fix and smog tested today, I had lots of time to consider how I should proceed, and I came across another thought.

        I currently have a Dell 2408WFP monitor that works - except it has a crack in the LCD panel. The circuit cards have all the replacement voltage regulators and Schottky diodes I need for this 2007WFP. Is it worth cannibalizing that, or should I concentrate on finding a replacement lcd for the 2408WFP?

        Replacement lcds are not available new, and it looks like the voltage regulators I need for the other are not so available either. All suggestions appreciated. I am going to post in the Wanted section my desire to purchase a 2408WFP lcd in case anyone knows of one.

        Thanks all.

        Comment


          Re: Dell 2007WFP Won't Power On

          Originally posted by LAS View Post
          I currently have a Dell 2408WFP monitor that works - except it has a crack in the LCD panel. The circuit cards have all the replacement voltage regulators and Schottky diodes I need for this 2007WFP. Is it worth cannibalizing that, or should I concentrate on finding a replacement lcd for the 2408WFP?
          1) I would leave the boards for the Dell 2408WFP alone.

          2) The key is to interpret the voltage regulators as per my post #68

          https://www.badcaps.net/forum/showpo...5&postcount=68

          3) Both the 1.8V and 2.5V 1A regulator are widely available at digikey.

          4) For U13, this looks suitable assuming the input voltage is less than 18V DC. As you know the power supply puts out 19V DC and I don't know if it is dropped down by the USB board before being fed into the logic board or not since I don't have a working system.

          http://search.digikey.com/us/en/prod...ICT-ND/2095617

          It is a 1.8V 1A TO-252-3 package.

          5) For U5, this should work

          http://search.digikey.com/us/en/prod...9-1-ND/1883984

          It is a 2.5V 1A SOT-223 package.

          6) For the diodes, I was looking at

          http://search.digikey.com/us/en/prod...RCT-ND/2486749

          A 40V 1A Schottky fast recovery diode in 0603 format.

          7) Fuse.

          http://search.digikey.com/us/en/prod...96-1-ND/615056

          8) All the above are 50 to 65 cents each and I would highly recommend you get extras because if two people in different countries have the exact same components going bad, you can bet in the future that it will fail again for whatever reason.

          9) So for about $3.00 in parts, this will hopefully fix the 2007WFP which is why I recommend not stealing parts from the 2408 as per #1.

          10) Please doublecheck sizing for all parts.
          Last edited by retiredcaps; 05-12-2012, 05:15 PM.
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          Comment


            Re: Dell 2007WFP Won't Power On

            A good plan!! Thank you Retiredcaps for the parts lists!!

            Comment


              Re: Dell 2007WFP Won't Power On

              I am not sure I should start a new thread for the Dell 2007 or not, I found 2 of them today at the recycle place and took it apart to check the voltages and draw up some diagram.
              I have about 52 pictures.
              Anyone of you think I should start a new thread or not.
              Thanks.
              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 2007WFP Won't Power On

                Originally posted by budm View Post
                Anyone of you think I should start a new thread or not.
                I think you should start a new thread with your pictures, analysis, diagram, etc and put a link back here.

                That way, it is more of a budm case study.
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                  Re: Dell 2007WFP Won't Power On

                  OK, will do.
                  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 2007WFP Won't Power On

                    Looking forward!

                    Comment


                      Re: Dell 2007WFP Won't Power On

                      Budm's teardown ...

                      https://www.badcaps.net/forum/showthread.php?t=20531
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                      We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

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                        Re: Dell 2007WFP Won't Power On

                        I have been thinking about how the discussion regarding these monitors is how the two Schottky diodes short out over time, possibly due to their relatively low 1a rating. Would anyone recommend replacement with 2a 40v diodes instead as shown in the link below?

                        http://search.digikey.com/scripts/Dk...3%2F61TGICT-ND

                        Comment


                          Re: Dell 2007WFP Won't Power On

                          I would replace them with ONE Shottky Diode with 3 or 4A rating instead, I do not believe in using two Diode in parallel. Since there is a lot of space, you can try through hole Diode. We already know that the original setup did not work.
                          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 2007WFP Won't Power On

                            Originally posted by budm View Post
                            I would replace them with ONE Shottky Diode with 3 or 4A rating instead, I do not believe in using two Diode in parallel. Since there is a lot of space, you can try through hole Diode.
                            I found a SF34G through hole diode on a junk board and will try a single diode hopefully in the next few days (forecast is rain for next 3 days). I have backlog of stuff including the Toshiba 46 inch TV to work on.
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                            Comment


                              Re: Dell 2007WFP Won't Power On

                              I hope the MOSFET did not get damaged when the Diodes shorted out.
                              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 2007WFP Won't Power On

                                Update on my project...I'm sorry to report that my logic card fix did not go well. The existing solder was the closest thing I've found to cement, and the parts just would not budge. I tried all the usual tricks - adding a little solder, adding a little flux, pressing the turbo button on my iron - and the board was damaged, and I screwed it up.

                                I started by removing the cap C155 next to the voltage regulators to make some more room. I ultimately got it out but it took one of the pads with it. And I've probably done fifty caps in the past year, and never had a problem.

                                Voltage regulator U5 went in cleanly, but the U13 was more difficult. And in the process, I damaged the microscopic C156 next to it. It just popped off, and it was so small I barely noticed it. And now either it's bad or put in badly - probably both but I could barely tell which side is up.

                                Anyway, they can't all be winners in this game and I already have my eye on another project for this weekend. But no doubt this one was a learning experience and the next one should go better. LAS.

                                Comment


                                  Re: Dell 2007WFP Won't Power On

                                  Hey Las,

                                  Your right there are some that might get the better of you but if you have only lifted a pad it wouldn't be the end of the world you can normally repair them.

                                  If its gone already then i'm sure you can make up for it with your next project! as a matter of interest what do you have your eye on?
                                  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 2007WFP Won't Power On

                                    Hoping to acquire a flickering Samsung 22 inch.

                                    A few months back, I was in possession of a flickering one, changed the caps, and took it to London with me as a present for a buddy of mine. I introduced him to the world of working with dual monitors and now he doesn't know he functioned all this time with just one.

                                    Comment


                                      Re: Dell 2007WFP Won't Power On

                                      Cool!

                                      I would never go back to working with one! keep us updated on the progress of your new project
                                      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 2007WFP Won't Power On

                                        Originally posted by LAS View Post
                                        IThe existing solder was the closest thing I've found to cement, and the parts just would not budge.
                                        Before I went to sleep last night and before your update/post above, I took out the heat gun to desolder both voltage regulators. I have tried in the past to desolder these 252 and 223 packages without success so I switched to the heat gun (aka poor man's hot air rework station with no temperature control).

                                        To protect everything around, I ordered 100 feet of Kapton tape ($4) and use it as a heat shield as you can see in the pictures. Both regulators came out with no problems after about 90 seconds of heat.

                                        Now remember, my in circuit readings suggested both U13 and U5 were shorted. Well U13 and U5 are fine. There are no shorts and I tested it with a 9V battery and both output the correct voltage.

                                        With both regulators removed, unfortunately, the pads still show a short. So there must be something else shorted on the logic board.

                                        Anyway, I wanted to share a tip about using Kapton tape in the future whether you use a soldering iron or heat gun.

                                        Note to self: Avoid this Dell model, even free, at all costs.
                                        Attached Files
                                        Last edited by retiredcaps; 05-18-2012, 12:33 AM.
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                                          Re: Dell 2007WFP Won't Power On

                                          Originally posted by retiredcaps View Post
                                          5) For U5, this should work

                                          http://search.digikey.com/us/en/prod...9-1-ND/1883984

                                          It is a 2.5V 1A SOT-223 package.
                                          @LAS I made a mistake on the digikey part number above. It was not obvious to me until I started measuring the voltage regulator out of circuit and I got weird results and then noticed the I G O markings. That is, pin 1 = VIN, pin 2 = GND, and pin 3 = VOUT.

                                          The above digikey one that I referenced is one I'm used to recommending (1117), but the pinout is G O I (pin 1 = GND, pin 2 = VOUT, pin 3 = VIN). This is what I'm used to seeing 99% of the time.

                                          As for the correct one, I will have to do some searching. Digikey's website doesn't search where I can input the pinouts.
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