Announcement

Collapse
No announcement yet.

Dell 1901fp

Collapse
X
Collapse
 
  • Page of 3
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 3 template Next
    #1

    Dell 1901fp

    Hey all, I hope this is in the right thread.

    I have previously fixed a ton of DELL motherboards with bad caps, but I have now been put to the test with two bad 1901fp lcd monitors. I have taken the inverter boards out on both and neither have bad caps. Atleast to the naked eye.

    Here's the problem. They have been powered up constantly at our office for about 8 years with little downtime. We have recently moved, and during the moving process, we tried to fire them back up and they were both no-goes. We get no response with power (and yes, the new outlets work). Now, I have done some research and have found that there can be some bad transistors on these boards. Hmmm. So, I was hoping someone has messed with this board in any way to find out maybe these caps could possibly not blow or leak, but just cause problems. They are the infamously crappy capXon caps. I know these inverter boards are the same as the DELL 1703fpt lcd's.

    If anyone can help, I would greatly appreciate it!!
    Tags: None
    #2
    Re: Dell 1901fp

    Originally posted by littlski717 View Post
    We get no response with power (and yes, the new outlets work).
    1) Post clear focused pictures with the following composition

    https://www.badcaps.net/forum/showpo...94&postcount=1

    Please do not post pictures inline as they slow down the loading of pages.

    For best picture quality and clarity take your boards to a window on a sunny day, turn flash off, and use macro mode. Take a top down view of all your boards (front and back). Make sure the photo is legible so that we can read the PCB printing clearly. A shutter speed of 1/125 or faster will produce nice clear focused pictures. Try to get a photo that is 2000x2000 resolution or as close as possible.

    2) Do you have a multimeter?

    Here is an example of the pictures we want.
    --- begin sig file ---

    If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

    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.

    Please do not post inline and offsite as they slow down the loading of pages.

    --- end sig file ---

    Comment

      #3
      Re: Dell 1901fp

      Originally posted by littlski717 View Post
      Hey all, I hope this is in the right thread.

      We get no response with power (and yes, the new outlets work).
      If anyone can help, I would greatly appreciate it!!
      Not even a power LED?
      Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

      Comment

        #4
        Re: Dell 1901fp

        Unfortunately no. I have no power led light. There is the 4 buttons on the front and the farthest to the right is the power button. No response from it.

        I'm trying to get some pics up, but i dont think it would even do any good. None of the caps look bad (no busts or curves to them). The 4 big caps did have very thin black marks that i could scrape off with my finger nail, so i'm not sure if they just used a marker on them or not. I wish someone has played with this exact board previously.

        Comment

          #5
          Re: Dell 1901fp

          Originally posted by littlski717 View Post
          Unfortunately no. I have no power led light. There is the 4 buttons on the front and the farthest to the right is the power button. No response from it.

          I'm trying to get some pics up, but i dont think it would even do any good. None of the caps look bad (no busts or curves to them). The 4 big caps did have very thin black marks that i could scrape off with my finger nail, so i'm not sure if they just used a marker on them or not. I wish someone has played with this exact board previously.
          It's relatively easy to troubleshoot the power supply using nothing more than a DMM. Having pictures to work from makes it easy to direct you. Since you haven't provided pictures, here are the general directions.

          With the power supply plugged in, measure the voltage on each pin of the output connector. Use one of the mounting screws as a ground. Report the readings.

          If there are no output voltages, measure the voltage across the large capacitor. This should read 1.4 X the AC input voltage. If that is present, what is the part number of the SMPS controller?

          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: Dell 1901fp

            Sorry everyone, I was gone for the holiday. I thank you for your help thus far.

            I took all of the voltages on the output pins and got a big fat nothing on all of the pins. So I moved on to your next step and found that the giant cap gave me nothing - high 600 millivolts at best. Is this a sign of a bad cap? Transistor? possibly the transformer?

            BTW, this may sound completely dumb, but which one of the numbers on this board would be the part number. Please have some patience with me. This is the first monitor I have played with.

            Comment

              #7
              Re: Dell 1901fp

              Originally posted by littlski717 View Post
              So I moved on to your next step and found that the giant cap gave me nothing - high 600 millivolts at best.
              Are you by chance measuring AC? If yes, we want to measure DC volts across the big cap and the output pins.
              --- begin sig file ---

              If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

              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.

              Please do not post inline and offsite as they slow down the loading of pages.

              --- end sig file ---

              Comment

                #8
                Re: Dell 1901fp

                Yeah I measured DC... I double checked again and im still getting nothing..

                Comment

                  #9
                  Re: Dell 1901fp

                  Okay now this goofy thing says 172 volts. So judging by the calculation, its a little over, but I know components aren't always perfect.

                  Comment

                    #10
                    Re: Dell 1901fp

                    Originally posted by littlski717 View Post
                    Okay now this goofy thing says 172 volts.
                    172V DC is fine. Now what about the output connector pins?
                    --- begin sig file ---

                    If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                    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.

                    Please do not post inline and offsite as they slow down the loading of pages.

                    --- end sig file ---

                    Comment

                      #11
                      Re: Dell 1901fp

                      And we are still waiting for pics as per post #2.
                      --- begin sig file ---

                      If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                      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.

                      Please do not post inline and offsite as they slow down the loading of pages.

                      --- end sig file ---

                      Comment

                        #12
                        Re: Dell 1901fp

                        Output connector is as follows:

                        blue and purple wires (labeled 5.15V on the board) are measured at 5.18V each.

                        All of the rest are goose eggs (0).

                        Comment

                          #13
                          Re: Dell 1901fp

                          I tried to take a couple pics, but my damn camera is broken. I took them with my phone, any idea how to get them up here?

                          Comment

                            #14
                            Re: Dell 1901fp

                            Alright, I got em. If you need anymore, let me know.
                            Attached Files

                            Comment

                              #15
                              Re: Dell 1901fp

                              Originally posted by littlski717 View Post
                              If you need anymore, let me know.
                              We also need pictures of the logic/main board (where your VGA/DVI connectors are).
                              --- begin sig file ---

                              If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                              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.

                              Please do not post inline and offsite as they slow down the loading of pages.

                              --- end sig file ---

                              Comment

                                #16
                                Re: Dell 1901fp

                                Here are the pics of the logic board.
                                Attached Files

                                Comment

                                  #17
                                  Re: Dell 1901fp

                                  Can you not crop it? We need to see the ENTIRE board edge to edge in ONE picture. The same goes for the power supply picture.

                                  See

                                  https://www.badcaps.net/forum/showpo...94&postcount=1

                                  for an example of the composition.
                                  --- begin sig file ---

                                  If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                                  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.

                                  Please do not post inline and offsite as they slow down the loading of pages.

                                  --- end sig file ---

                                  Comment

                                    #18
                                    Re: Dell 1901fp

                                    I did crop it. Unfortunately this is where mac sucks compared to windows. It cuts parts of the pics off. I will try again right now.

                                    Comment

                                      #19
                                      Re: Dell 1901fp

                                      Here ya go!
                                      Attached Files

                                      Comment

                                        #20
                                        Re: Dell 1901fp

                                        Originally posted by littlski717 View Post
                                        They have been powered up constantly at our office for about 8 years with little downtime.

                                        We have recently moved, and during the moving process, we tried to fire them back up and they were both no-goes.
                                        I'm not a screen wizard like these other guys but: reading the sequence of events..

                                        Transistors in -two- screens aren't likely to suddenly fail at exactly the same time, nor from being moved.
                                        The screens also wouldn't work at all if those were shot before you moved, so if they 'went' it was when you moved them.
                                        .
                                        Since you never turn them off,, the start-up caps may have bit the big one weeks or months before you moved and you didn't notice because that probably wouldn't kill a screen that is already running and you never restart them to see the problem.
                                        - Until you moved them.
                                        .
                                        Last edited by PCBONEZ; 11-27-2011, 05:16 AM.
                                        Mann-Made Global Warming.
                                        - We should be more concerned about the Intellectual Climate.
                                        -
                                        Be who you are and say what you feel, because those who mind don't matter and those who matter don't mind.
                                        - Dr Seuss
                                        -
                                        You can teach a man to fish and feed him for life, but if he can't handle sushi you must also teach him to cook.
                                        -

                                        Comment

                                        Previous 1 2 3 template Next
                                        Working...
                                        X