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    #81
    Re: Dell E172fpb

    Had the same problems as you guys.
    Picture came on for 2 secs, and then went off.
    Found and replaced shorted Q759 and Q760 with identical models.
    Turned on, and the screen and led flashes on and off with a ticking sound.

    Any ideas? Should I remove the two associated transformers and test resistance, resolder board, or replace caps, or all of the above!?!

    Thanks

    Comment


      #82
      Re: Dell E172fpb

      I just picked up a dead one of these monitors with the same symptoms described over and over again here. To make sure I understand:

      The problem is not the caps, but the soldering, which then fries the caps.

      Which leaves me the option of replacing lots of caps and other bits. OR getting a replacement board.

      Let me be absolutely clear: I know NOTHING about electronics except what I've read on this thread.

      Two more questions:

      1. So I want to know if anyone who has used the remanufactured inverter from Norris has found it to be significantly better than the original?

      2. It seems that learning to work with electronics on some basic level would be a very useful skill, especially given that I don't trust service centers. Can you guys recommend a book, or learning kit that would be good and not cost a gazillion bucks?
      I'm Hooliator, and I approved this message.

      hooliator.net

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        #83
        Re: Dell E172fpb

        An occupational school offers courses which I used to do.
        Your library is a huge resource and it goes without saying that the web has a lot.
        But reguardless of your knowledge I think others can agree that the aptitude has to be there and good assembly skills.
        Jim

        Comment


          #84
          Re: Dell E172fpb

          I've learned a lot about electronics in the last few months with just books and the web. Once I but a scope, I'll be set. The only thing that sucks learning by yourself is without schematics or years of seeing the same circuits over and over again, I get a little lost and it can take a log time to find my way back home. Forums like this are a great places to ask specific questions. Who knew researching a dead board one day would turn me into elektronotical genius!

          Comment


            #85
            Re: Dell E172fpb

            Lesson for the future? don't buy BenQ?
            I'm Hooliator, and I approved this message.

            hooliator.net

            Comment


              #86
              Re: Dell E172fpb

              Can anybody tell me if these connections are correct, i.e. white / white to CN755, Pink / black CN754, white / white CN752, Pink / black CN753? I've had it disconnected for some time and I've lost the photo I took to remind me where they go!

              Comment


                #87
                Re: Dell E172fpb

                If anyone has one of these boards they want to lose, then I want to find it. I'll pay $15 ($5 more than Norris) for one that still has at least 2 good transformers on it.

                Also: can any of y'all recommend a brand/type of solder which holds up well under the oven-like conditions that our lovely little Benny produces?
                I'm Hooliator, and I approved this message.

                hooliator.net

                Comment


                  #88
                  Re: Dell E172fpb

                  Originally posted by sjbso2000
                  Can anybody tell me if these connections are correct, i.e. white / white to CN755, Pink / black CN754, white / white CN752, Pink / black CN753? I've had it disconnected for some time and I've lost the photo I took to remind me where they go!
                  Anybody?

                  Comment


                    #89
                    Re: Dell E172fpb

                    Please? Anybody? My monitor still doesn;t work after replacing components. I may have the connections mixed up. But if I haven;t and I change them and it goes up in smoke I'll be even more p'd off.

                    Thanks

                    Comment


                      #90
                      Re: Dell E172fpb

                      Item number 110037232214

                      Here is one on ebay bidding at $9.99 with 2dys left at the moment.
                      The screen is shattered, as is.
                      Jim

                      Comment


                        #91
                        Re: Dell E172fpb

                        Originally posted by Hooliator
                        If anyone has one of these boards they want to lose, then I want to find it. I'll pay $15 ($5 more than Norris) for one that still has at least 2 good transformers on it.

                        Also: can any of y'all recommend a brand/type of solder which holds up well under the oven-like conditions that our lovely little Benny produces?
                        time to cut a 80x80mm hole and install a fan?
                        btw looks like you are also on cpf?

                        Comment


                          #92
                          Re: Dell E172fpb

                          I'm sorry I don't know what "cpf" is... but maybe. I'm on a lot of things. Perhaps you could clarify the acronym?

                          As at least one of you already knows (sorry...) I got the monitor on ebay.

                          I was a bit surprised when I opened it. My two monitors were not the same...

                          Turns out the crappy burned out ben-q was the 173FPb and the broken screen one was the 172FPt. And lucky for me too because while the inverter and logic cards were completely different, the screens were the same model. I was able to swap the burny ben-qy screen for the busted screen. And now I have a working monitor!

                          A couple of little things I noticed: The burned out monitor was generally of a poorer quality construction. The base was lighter, and what really got to me was that the screws were cheaper. Many of them got torn up with normal turning pressure, one I couldn't get out because the groove stripped on the first turn. I didn't have that problem on the 172.

                          I've attached a zip file with pics of the inverter board from the 172. It's the model of simplicity. That's probably why it still works.

                          I'm selling my old inverter board. It's not as badly discolored as a lot of the one's that have been shown on this thread. I think it has some salvaglable transformers. If anyone needs other parts let me know, I've got everything except the screen all disassebled and ready to part out. Check back in the 'for sale' threads. I'll try to post it all by Sunday Oct 7.
                          Attached Files
                          I'm Hooliator, and I approved this message.

                          hooliator.net

                          Comment


                            #93
                            Re: Dell E172fpb

                            I've listed all or most of the parts which I've salvaged from my "old" monitor.

                            They are listed in the For Sale forum under "Parts for Dell E172FP"
                            https://www.badcaps.net/forum/showthread.php?t=2769

                            I've listed the following parts:
                            Inverter Board (BENQ DS-1107A)
                            Logic Card (also BenQ)
                            Bus Cable
                            Lighting Tubes (4)

                            Prices are negotiable, shipping is extra. I won't gauge you on the shipping.
                            I'm Hooliator, and I approved this message.

                            hooliator.net

                            Comment


                              #94
                              Re: Dell E172fpb

                              Hello

                              I ve had the same problem as many with an E172fpb BenQ and the infamous flashing led after 1 sec.

                              I had to change two transistors out of the group of four located near the plugs for ccfl.

                              I used two BD911 from SGS mounted externally on radiators (heat !!!) and everything worked fin ... until yesterday (that 's 6 days after the repair)

                              When screen is in use, np. But after 2 hours or so, the top ccfl goes dimm for 2 sec or so and screen turns off completely. If i let it cool down, it restarts and is running as it should ... for two hours or so and so on and so on...

                              It fells like a thermal problem somewhere, humm ?

                              but the radiator i fixed on the trans. is merely hot to the touch, the specsheet talks about 150 deg. C junct Temparature, so i guess the pb is somewhere else...

                              Do you think the BD 911 is wrong ? i couldnt find any C5707 in my little french town... I think BD 911 has an Hfe or about 40 where 5707 is typically 200..

                              Could this not be enough and ccfl turns off ?

                              Or do the CCfl sometimes get tired and need repl. ?

                              Can anyone help ?

                              Comment


                                #95
                                Re: Dell E172fpb

                                If it really is a heat problem try running it with the back cover off and a desk fan blowing air at it...
                                "The one who says it cannot be done should never interrupt the one who is doing it."

                                Comment


                                  #96
                                  Re: Dell E172fpb

                                  Hi !
                                  Thanks for answering...

                                  This is strange...

                                  The firts time the screen switched off was after 5 hours running.
                                  The second after 2 hours
                                  Then 1 hour and lately 15 mins...


                                  I'm a bit reluctant to open it all again i have to say...

                                  But i think you are right: i will try that when i have time...

                                  Thanks

                                  Comment


                                    #97
                                    Re: Dell E172fpb

                                    hi

                                    i have two dell E172FPB WITH BLACKLIGHT PROBLEMS!!!!

                                    On the Inverterboard i have replaced the c5707 transistors and it was only working fine for a couple of days. The same transistors went bad again could anyone help me.

                                    Comment


                                      #98
                                      Re: Dell E172fpb

                                      Folks, see my earlier posts

                                      If you have not spent 20min with a cheap solder sucker and resoldering the heat affected areas then the above symptons that sound like everything is working fine but the time working becomes less and less means the crappy solder and heat combination is dry jointing the board.

                                      I'm up to seven repairs and this resolder is mandatory with no failures from daily use and the first experiment at page three is still in daily use by one happy son.

                                      If I could tell you which dry joint then I would but have not been able to limit to a part. I'm the one with four cheap trannies mounted external and heatsinked in the cavity between vga and power. The heatsink used was approx 9cm x 6cm then cut in four, glued with paddlepop sticks to isolate the trannies, as I didn't bother with any insulating spacers at the time given I didn't know reliability from the first attempt. Later ones used half the size sinks and insulated as they are for friends who want the repair and don't mind the hidden external mount if this keeps the heat out.

                                      Comment


                                        #99
                                        Re: Dell E172fpb

                                        Hi !

                                        Thanks for your tip !

                                        So you think it is just due to poor soldering ?

                                        My trans are mounted externally: no heat there...

                                        I will try to find something inside when i get the time

                                        Comment


                                          Re: Dell E172fpb

                                          Just run a solder iron over any joint in the heat affected area and if you have soldered before, you will quickly reaslise the cheap mix they used and from earlier posts, the solder always quickly parted from the pins which were dirty from the start of the manufacturing process.

                                          Use your multimeter to watch if you have rise after the job to see if steady over 5 to 10 min before putting back together. again I mention the diode used as the test point, Cheers

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