Announcement

Collapse
No announcement yet.

Dell u2312

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

    Dell u2312

    Hi,

    Got one of these to fix yesterday. I havent looked at an LED one before so I need a little guidance.

    The monitor when plugged in shows no sign of life at all. I have stripped it down and plugged in the power supply and mainboard without having the monitor connected. The big cap is showing 330v and there dows seem to be voltage getting to the mainboard as I quickly tested the voltage regulators. I havent checked to see if they are correct yet which will be my next step.

    Pics are only quick ones and as its dark here I had to use the flash but hopefully they will you give you an idea of what I am working on.
    Attached Files
    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
    Tags: None
    #2
    Re: Dell u2312

    Originally posted by Jasgriff View Post
    The monitor when plugged in shows no sign of life at all.
    If the power LED is green, that implies the main board is working.

    If there is no power led at all, then check the voltage regulators using my guide below.
    --- 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 u2312

      Right...

      I301 = 3.3v
      I302 = 2.1v
      I308 = 0v

      P306 is a ribbon connector that connects to the switch panel. There seems to be 3.3v present on some of those pins.
      Attached Files
      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

        #4
        Re: Dell u2312

        I308 is a 3.3V output regulator. Are you at least seeing a 5V input for I308?

        Comment

          #5
          Re: Dell u2312

          Im getting nothing at all on any pin of I308. There are a few SMD fuses on the board too which I have been testing none of which are blown so far.
          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

            #6
            Re: Dell u2312

            Are you talking about F302 and F303?

            Comment

              #7
              Re: Dell u2312

              Yes there is a F301, F304 and F305 too they are all measuring 2 Ohms
              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

                #8
                Re: Dell u2312

                I308- The rightmost leg is the input. Left leg is ground and middle leg (and tab) is the output. Try tracing the input leg to see what's feeding it.

                Comment

                  #9
                  Re: Dell u2312

                  Originally posted by Jasgriff View Post
                  Right...

                  I301 = 3.3v
                  I302 = 2.1v
                  I308 = 0v

                  P306 is a ribbon connector that connects to the switch panel. There seems to be 3.3v present on some of those pins.
                  I prefer readings for all the 3 pins for a reason.

                  The reason is that I302 could an adjustable regulator or it could be a fixed regulator. The 2nd line of the part number begins with 12 would could mean it is a fixed 1.2V regulator. If I'm correct, pin 1 on I302 should be 0.0V volts. That would mean I302 is bad (unless you transposed the numbers).

                  I'm leaning towards a fixed regulator because I see no SMD resistors between pin 1 and pin 2.

                  This is why I wrote the guide to ask for all readings. There is a lot of mis-interpretation of the readings by people.
                  Last edited by retiredcaps; 09-05-2012, 01:22 AM.
                  --- 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

                    #10
                    Re: Dell u2312

                    Originally posted by Jasgriff View Post
                    Yes there is a F301, F304 and F305 too they are all measuring 2 Ohms
                    No properly working Fluke will give a reading of 2.0 ohms for a fuse. You must mean 0.2 ohms.

                    Details and precision matters (as per post #9). I would like to see all the digits (resolution) of the readings.

                    You get great marks for clear focused photographs.
                    Last edited by retiredcaps; 09-05-2012, 01:52 AM.
                    --- 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 u2312

                      Originally posted by retiredcaps View Post
                      No properly working Fluke will give a reading of 2.0 ohms for a fuse. You must mean 0.2 ohms.

                      Details and precision matters (as per post #9). I would like to see all the digits (resolution) of the readings.

                      You get great marks for clear focused photographs.
                      Retiredcaps all valid points and again noted.

                      I did a little playing around with the monitor again this morning so I will write up my findings shortly along with some accurate readings.
                      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

                        #12
                        Re: Dell u2312

                        Right,

                        I301
                        N252
                        G1084-33

                        Pin 1 = 0v
                        Pin 2 = 3.345v
                        Pin 3 = 5.209v

                        I302
                        GTC
                        LD1117AG
                        12A010HUE

                        Pin 1 = 0v
                        Pin 2 = 1.205v
                        Pin 3 = 3.345v

                        I308
                        Dll1ib
                        17-33

                        Pin 1 = 0v
                        Pin 2 = 0v
                        Pin 3 = 0v

                        On the Fuses. I meant 0.2 Ohms again my mistake.

                        Looking at I308 it seems to be connected to the USB hub which this monitor has. I do recall someone on here mentioning that the monitor wont power up without the usb hub connected?
                        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

                          #13
                          Re: Dell u2312

                          You jarred my memory with the USB card. It's true that some other Dell models required the usb card be connected in order for to start. I don't know if it applies to your model. Before you connect the usb card, inspect it for a blown fuse. If the fuse is good, then connect it and check I308 again.

                          Comment

                            #14
                            Re: Dell u2312

                            Originally posted by Jasgriff View Post
                            I302
                            LD1117AG
                            12A010HUE

                            Pin 1 = 0v
                            Pin 2 = 1.205v
                            Pin 3 = 3.345v
                            Okay, I302 is good. Move onto jetadm123's suggestion.

                            PS. Is the power LED on at all?
                            --- 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

                              #15
                              Re: Dell u2312

                              Ok,

                              There were a number of fuses that seemed to be connected to the on board usb ports and the external ones. I checked them both and none were blown. I then reconnected the external usb's and tested for voltage again and still got nothing I also tried a usb stick with a light on in the on board and and external usb and that didn't have any sign off life either.

                              I am now thinking that there should be 5v's kicking about going into the usb's that maybe also fed the third voltage regulator?
                              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

                                #16
                                Re: Dell u2312

                                Right done a little measurements from P802 on the power supply which connects to the signal board.

                                PWM = 2.514v
                                EN = 0v
                                5v = 5.209v
                                5v = 5.209v
                                5v = 5.209v
                                GND = 5.209v
                                GND = 0v
                                5v = 0v
                                ENA = 0.0v
                                EN = 0.102v
                                5v = 5.209v
                                RTNA = 0.008v
                                DET = 0v

                                After looking at the markings and then trying to double check them as it didnt seem right I noticed that they have put the connector on back to front.

                                Has anyone ever seen this before?
                                Attached Files
                                Last edited by Jasgriff; 09-17-2012, 10:35 AM.
                                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

                                  #17
                                  Re: Dell u2312

                                  Does the power led come and stay on?
                                  --- 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 u2312

                                    The power LED doesnt come on at all.
                                    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

                                      #19
                                      Re: Dell u2312

                                      See if the voltages go to the front keyboard. See if pressing the on/off button causes a voltage change or not.
                                      --- 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

                                        #20
                                        Re: Dell u2312

                                        Had to order some clips to hold my probes on whilst I was pressing the buttons so sorry for the delay.

                                        I have 3.3v on the on/off button and when its pressed it goes down too 0v.
                                        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

                                        Previous 1 2 template Next
                                        Working...
                                        X