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    Dell ST2010 with a dim display

    This monitor is in reference to the post below.
    https://www.badcaps.net/forum/showthread.php?t=21044

    I finally went and picked this monitor up. As you can see the bulbs fully function but the display is very dim. It uses 2 bulbs, 1 at the top and bottom. I plugged in a set of spare bulbs pulled from a 19" tv with a broken screen that was the same diameter as whats in this monitor. I pulled the panel and hooked it up to a 24" lcd tv and it appears brighter but you be the judge. Brightness control makes no difference. I tested the caps and they are all well within spec. Could the panel itself be driving the power supply down causing the dim display with a source and a somewhat normal glow with the lvds cable disconnected. I took the photos in the basement with the lights out so the pictures may look a little grainy but you'll get the idea.
    Attached Files

    #2
    Re: Dell ST2010 with a dim display

    Forgot the pictures of the power supply. What is the purpose of the blue caps by the inverter transformer? If i ohm them out, one reads 13 Mohm but the other doesn't give me a reading at all (OL)
    Attached Files

    Comment


      #3
      Re: Dell ST2010 with a dim display

      They are Ballast caps for the lamps, usually rated at 3000V or higher, it should show completely open circuit, if your meter can read the resistance, that is not good since the meter will put out less than 5V at the probes, so when these caps are exposed to about 2000V when the lamps start up, they can break down. There should be something like xxJ 3KV or 6KV printed on them.
      Not sure about the display problem, still trying to figure out your statement "I pulled the panel and hooked it up to a 24" lcd tv and it appears brighter" Do you mean, you use this Dell panel in the 24" LCD TV chassis?
      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


        #4
        Re: Dell ST2010 with a dim display

        Originally posted by budm View Post
        "I pulled the panel and hooked it up to a 24" lcd tv and it appears brighter" Do you mean, you use this Dell panel in the 24" LCD TV chassis?
        Yes, that is exactly what i did.

        So if my meter shouldn't read resistance of the ballast caps would the one that read 13 Mohm be considered bad?

        Comment


          #5
          Re: Dell ST2010 with a dim display

          I would replace that cap, might as well do all 4.
          When you take one panel from one monitor/TV and install it in another monitor, the picture may not look right when use it in another chassis since they have calibrated that screen (White balance, color, gamma, etc. and store that info in the flash in the T-CON) with that chassis, and all the signal lines mat not be the same even the plug does fit.
          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


            #6
            Re: Dell ST2010 with a dim display

            I'm going to see if i have a cap with the same rating on some of my junk power supplies. When i hooked the dell panel to the other chasis i didn't hook up the lvds cable. All i wanted to see was the bulbs on.

            Comment


              #7
              Re: Dell ST2010 with a dim display

              Oh, I see, so the pictures are from the original Dell screen and chassis.
              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


                #8
                Re: Dell ST2010 with a dim display

                Originally posted by Mr Bill View Post
                If i ohm them out, one reads 13 Mohm but the other doesn't give me a reading at all (OL)
                What make and model do you have? Some multimeters may only go up to 20 Mohm especially if it is a 2000 count multimeter.
                --- 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


                  #9
                  Re: Dell ST2010 with a dim display

                  Pictures 1 and 2 are the original panel and chasis. Picture 2 is with the lvds cable disconnected from the tcon.

                  Picture 3 is the dell panel hooked up to a viewsonic power supply with the lvds disconnected from the tcon

                  Comment


                    #10
                    Re: Dell ST2010 with a dim display

                    Originally posted by retiredcaps View Post
                    What make and model do you have? Some multimeters may only go up to 20 Mohm especially if it is a 2000 count multimeter.
                    It's a craftsman 82040 Autoranging multimeter

                    Comment


                      #11
                      Re: Dell ST2010 with a dim display

                      How do you decode the ballast caps? What i have now is:

                      C
                      3D
                      3KV

                      I looked through my power board that were pulled from monitors with defective screens and the closet i found was:

                      5D
                      3KV

                      I checked all the ballast caps on all my boards and i'm getting OL on all of them.

                      Comment


                        #12
                        Re: Dell ST2010 with a dim display

                        3d 3KV = 3 pF 3000Volts, they are have to be the same value as original or it may burn up the transformer or shorten the lamp life if the value is bigger than the original since it will draw more current, smaller value than original may cause the lamp not to fire up and stay lit.
                        If they all show OL with the highest Ohm range setting, then they more likely to be OK, when they are going bad, the body will turn light brown from the heat due to resistance leakage.
                        Last edited by budm; 07-13-2012, 10:54 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


                          #13
                          Re: Dell ST2010 with a dim display

                          I think i'm going to need some help finding these caps at digikey. If i put 3pf 3000v in the search field it's only giving me a 33pf cap. Here are the values on the 2 ballast caps that i need to order.

                          N15
                          3KV

                          and the other one is

                          C
                          3D
                          3KV
                          JNC

                          Thanks for any help

                          Comment


                            #14
                            Re: Dell ST2010 with a dim display

                            Originally posted by Mr Bill View Post
                            I think i'm going to need some help finding these caps at digikey. If i put 3pf 3000v in the search field it's only giving me a 33pf cap. Here are the values on the 2 ballast caps that i need to order.

                            N15
                            3KV

                            and the other one is

                            C
                            3D
                            3KV
                            JNC

                            Thanks for any help
                            One of "upsides" of reading every thread is that I remember obscure stuff that will eventually help. From jetadm123,

                            https://www.badcaps.net/forum/showthread.php?p=250424

                            If you change the criteria to 3.15kV, then you get

                            http://www.digikey.com/product-detai...201-ND/1021849
                            --- 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 ST2010 with a dim display

                              I do have 1 concern retired. In post #12 Bud listed 3D=3Pf. All the digikey searches i have done keep showing 33pf. Do you know of a site that decodes ceramic caps?

                              Thanks

                              Comment


                                #16
                                Re: Dell ST2010 with a dim display

                                You could probably use 3.3pF instead of 3pF.
                                Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                                For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                                Comment


                                  #17
                                  Re: Dell ST2010 with a dim display

                                  I found a replacement ballast cap and swapped it out but it didn't fix anything. So i opened up the screen and what do i see but some cooked ccfl wiring. I resoldered the cooked wire and hooked it up to another monitor i had to see what the bulb looked like. When the bulbed first turned on it was dim for almost 10 seconds then it went to full brightness. So i rechecked my soldering and i broke the stupid bulb .

                                  I had a 19" widescreen spare bulb so i put it in. I'm gonna give the monitor to my mother-in-law and she's not picky. Surprisingly the monitor doesn't really show dark corners. So i don't know if the bulb was going bad but my guess is the wiring was the culprit.
                                  Attached Files

                                  Comment


                                    #18
                                    Re: Dell ST2010 with a dim display

                                    Sometime I do use shorter lamps, and as you see, you can hardly tell that the lamps are shorter than the original, great job by the way, you do some time have to dig deep to inspect the lamp assemblies.
                                    I just fixed for three Dell 2208WFPF yesterday, all with burnt out wires on the lamp assemblies, very delicate works:
                                    https://www.badcaps.net/forum/showth...321#post251321
                                    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

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