Dell e173fpb - backlight

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  • yofreke
    New Member
    • Feb 2011
    • 3

    #1

    Dell e173fpb - backlight

    so our dell monitor pooped out a while ago, here's what i have done on it so far. Power light was flashing. Bought a replacement kit for 6 of the thingamabobers (black plastic front, metal plate on back, three prongs, labled: Q739, Q740, Q743, Q751, Q759, Q760). Lost interest, regained interest, plugged the monitor in to see where i was, and it started spewing a good amount of smoke. Replaced every one of the thingamabobers. Now it will turn on, and after ~1 second the backlights turn off (it is still on however). Checked all of the capacitors, none of them have bulged caps. Gave it a thorough look over, no visible smoke residue or bad looking solder connections.

    Hope that this problem hasn't already been addressed somewhere else, but i didn't see mention of a problem where it had done this. Thanks for any help.
  • seanc
    Badcaps Legend
    • Nov 2008
    • 1319

    #2
    Re: Dell e173fpb - backlight

    Resolder all transformer legs!

    Comment

    • sabre504
      Badcaps Veteran
      • May 2010
      • 449
      • United Kingdom

      #3
      Re: Dell e173fpb - backlight

      As Seanc said resolder the legs on the underside of the board
      Attached Files

      Comment

      • smason
        Badcaps Legend
        • Feb 2010
        • 1652
        • Canada

        #4
        Re: Dell e173fpb - backlight

        Thingamabobers? Seriously?
        36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

        Comment

        • yofreke
          New Member
          • Feb 2011
          • 3

          #5
          Re: Dell e173fpb - backlight

          Originally posted by sabre504
          As Seanc said resolder the legs on the underside of the board
          Alright, so just remove current solder, take them out, read to them some, put them back in? I will do it, but why?

          Originally posted by smason
          Thingamabobers? Seriously?
          Shh, i'm a visual type of person.

          Comment

          • sabre504
            Badcaps Veteran
            • May 2010
            • 449
            • United Kingdom

            #6
            Re: Dell e173fpb - backlight

            You dont have to take them out just clear old solder and put fresh in
            these are reknowned for poor solder joints on the transformer legs

            Comment

            • smason
              Badcaps Legend
              • Feb 2010
              • 1652
              • Canada

              #7
              Re: Dell e173fpb - backlight

              <disclaimer> I've had a couple </disclaimer>

              Originally posted by yofreke
              I will do it, but why?
              I'm tempted to say "because we effing told you" but I'll be nice

              In semi-non-technical terms:
              A very common failure mode on this model is that there are bad solder joints on the inverter transformers. This causes the controller to drive the transistors harder.

              Scotty: "Kiptain, the backlights are nay gettin enough pow'r, I'll tell the trannies to kick it up a wee bit"

              Kirk: "Who the eff let trannies on my ship"

              Sulu: "Oooh, did someone say trannies??",

              Anyway, the c5707s and the Fets of which I canna rememerrrr the parrrt number die (usually shorting oot) and sometimes takes out the picofuse just for grins.

              Some folks have replaced the fuse and the bad transistors, only to have the same thing happen again, because they dinna resolder the transforrrrmers.

              That's my understanding of the situation filtered through about 3 Crown Royals, and a beer or 2.
              36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

              Comment

              • retiredcaps
                Badcaps Legend
                • Apr 2010
                • 9271

                #8
                Re: Dell e173fpb - backlight

                Originally posted by yofreke
                Alright, so just remove current solder, take them out, read to them some, put them back in? I will do it, but why?
                Possible technical explanation ...

                https://www.badcaps.net/forum/showpo...&postcount=269
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                Comment

                • hoadle
                  Senior Member
                  • Jul 2010
                  • 174

                  #9
                  Re: Dell e173fpb - backlight

                  Some time is ccfl backlight is bad that cost shut off too,

                  Comment

                  • yofreke
                    New Member
                    • Feb 2011
                    • 3

                    #10
                    Re: Dell e173fpb - backlight

                    Originally posted by smason
                    <disclaimer> I've had a couple </disclaimer>



                    I'm tempted to say "because we effing told you" but I'll be nice

                    In semi-non-technical terms:
                    A very common failure mode on this model is that there are bad solder joints on the inverter transformers. This causes the controller to drive the transistors harder.

                    Scotty: "Kiptain, the backlights are nay gettin enough pow'r, I'll tell the trannies to kick it up a wee bit"

                    Kirk: "Who the eff let trannies on my ship"

                    Sulu: "Oooh, did someone say trannies??",

                    Anyway, the c5707s and the Fets of which I canna rememerrrr the parrrt number die (usually shorting oot) and sometimes takes out the picofuse just for grins.

                    Some folks have replaced the fuse and the bad transistors, only to have the same thing happen again, because they dinna resolder the transforrrrmers.

                    That's my understanding of the situation filtered through about 3 Crown Royals, and a beer or 2.
                    So even if the connections look fine, they could actually be bad? Just re-melting the connections won't do (cheap soldering wick is the devil)?

                    EDIT: Also, which fuses will need checking? I'm too unfamiliar with LCD repair, as this is the first one i'm tackling.
                    Last edited by yofreke; 02-20-2011, 09:04 PM.

                    Comment

                    • smason
                      Badcaps Legend
                      • Feb 2010
                      • 1652
                      • Canada

                      #11
                      Re: Dell e173fpb - backlight

                      Originally posted by retiredcaps
                      Yeah, that's what I meant to say...
                      36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

                      Comment

                      • killian6pk
                        Badcaps Veteran
                        • Apr 2010
                        • 502
                        • USA

                        #12
                        Re: Dell e173fpb - backlight

                        Originally posted by smason
                        <disclaimer> I've had a couple </disclaimer>



                        I'm tempted to say "because we effing told you" but I'll be nice

                        In semi-non-technical terms:
                        A very common failure mode on this model is that there are bad solder joints on the inverter transformers. This causes the controller to drive the transistors harder.

                        Scotty: "Kiptain, the backlights are nay gettin enough pow'r, I'll tell the trannies to kick it up a wee bit"

                        Kirk: "Who the eff let trannies on my ship"

                        Sulu: "Oooh, did someone say trannies??",

                        Anyway, the c5707s and the Fets of which I canna rememerrrr the parrrt number die (usually shorting oot) and sometimes takes out the picofuse just for grins.

                        Some folks have replaced the fuse and the bad transistors, only to have the same thing happen again, because they dinna resolder the transforrrrmers.

                        That's my understanding of the situation filtered through about 3 Crown Royals, and a beer or 2.
                        That was absolutely great. Are you available for parties.
                        Have you ever stopped to think and then forget to start thinking again?

                        As a very wise man once said on this forum: "Of all the things I have lost I miss my mind the most."

                        Comment

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