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Fix for Benq FP737s 17" (Q7T3)

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    Re: Fix for Benq FP737s 17" (Q7T3)

    Originally posted by vicrowley
    Hi Dave,
    I have recently been given one of these Benq 17” monitors, but only because it had died. I'm only an amateur dabbler in electronics, and I think I've just about been able to follow most of your circuit mods, and the reasoning behind them. Now I know from the dates on the posted articles, it was some time ago you were working on this monitor, but I was wondering if you now have a final definitive modification list, and final circuit diagrams. I ask this as reading through the various posts, you were obviously developing and changing things as you found new problems, and from reading through, it is hard to be sure I'm using your final solution for all the mods.

    PS. I hope I've entered this in the right place, I'm new to this forum.

    Vic
    Welcome to the forums.
    While the post is in the right place, you might want to PM davmax directly.
    There are 10 kind of people in this world: those that understand binary, and those who don't.
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    Comment


      Re: Fix for Benq FP737s 17" (Q7T3)

      Thanks, will look and see how to do that.

      Vic

      Comment


        Re: Fix for Benq FP737s 17" (Q7T3)

        In response to a request for the final modification details
        I have made this easy by posting the final versions at an online album here: http://picasaweb.google.com.au/davmax60/MonitorRepairs#

        Use the full screen facility to see the detail.

        Please note that there are two versions of current sense resistor, either a single resistor or two in parallel. Therefore the photo of the board underside shows the 0.082 ohm resistor version (alternately this resistor would be 0.56 ohm). The photo of the upper board shows the position of the 0.1 ohm resistor.
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        Comment


          Re: Fix for Benq FP737s 17" (Q7T3)

          I feel I should add that to achieve the modification I describe you will need all the tools.
          A soldering iron and self fluxing solder.
          A PCB drill and bit 0.8 - 1 mm
          A sharp knife to cut tracks.
          Gigabyte EP45-DS3L Ultra Reliable (Power saver)
          Intel E8400 (3000Mhz) Bios temps. 4096Mb 800Mhz DDR2 Corsair XMS2 4-4-4-12
          160Gb WD SATAII Server grade
          Nvidia 8500GT 256Mb
          160Gb WD eSATAII Server grade for backup.
          Samsung 18x DVD writer
          Pioneer 16x DVD writer + 6x Dual layer
          33 way card reader
          Windows XP Pro SP3
          Thermaltake Matrix case with 430W Silent Power
          17" Benq FP737s LCD monitor
          HP Officejet Pro K5300 with refillable tanks

          Comment


            Re: Fix for Benq FP737s 17" (Q7T3)

            Thanks for the advice, and as far as the actual work of the board is concerned, I'm fairly confident on that score. In the past when I used to work for my living (now retired), I was for a few years in a data collection lab, and soldering strain gauges, some of which were only thirty thou long, and that included the two solder tags. So we had to work under a 30 to 1 microscope. I guess that's why I now need glasses. So like say the physical stuff I can deal with, it's the technical working of these modern electronics I know nothing about. It's all black boxes (Chips), and unless I know what each of these does and how it achieves it, I'm lost. So thanks for doing all the hard work, and I'll let you know once I've completed the task, if my confidence was well founded or not.

            Vic

            Comment


              Re: Fix for Benq FP737s 17" (Q7T3)

              Hi Everybody,

              Thanks all of you for the useful postings which help me to repair a BenQ FP731.
              It does not have any display with the green LED stays on.

              Things done
              -------------
              1. Replaced fuse (BEL MS 3A), PF751 is open-circuit. I used a 2A pico fuse because I do not have a 3A fuse on hand.

              2. Solder inverter transistors (2SC5707), Q739, Q740, Q759 and Q760. The solder cracked when I moved these 4 transistors.

              3. Solder power MOSFETs (FU9024N), Q743 and Q751. The solder cracked when I moved these 2 MOSFETs.

              4. Solder transformers, T751, T752, T753 and T754. No solder cracked, just re-solder to prevent dry joints.

              5. After power on, left half of the monitor displays information correctly but right half has pink background with a continuous black line in the centre of the screen.

              6. Remove the two flex-cables and clean the contacts (dirt found) with alcohol.

              7. Power on and the monitor is in working condition.

              Once again, thanks all you for the important information.

              Have a nice weekend...Yong Seng

              Comment


                Re: Fix for Benq FP737s 17" (Q7T3)

                Originally posted by Lim Yong Seng
                Hi Everybody,

                Thanks all of you for the useful postings which help me to repair a BenQ FP731.
                It does not have any display with the green LED stays on.

                Things done
                -------------
                1. Replaced fuse (BEL MS 3A), PF751 is open-circuit. I used a 2A pico fuse because I do not have a 3A fuse on hand.

                2. Solder inverter transistors (2SC5707), Q739, Q740, Q759 and Q760. The solder cracked when I moved these 4 transistors.

                3. Solder power MOSFETs (FU9024N), Q743 and Q751. The solder cracked when I moved these 2 MOSFETs.

                4. Solder transformers, T751, T752, T753 and T754. No solder cracked, just re-solder to prevent dry joints.

                5. After power on, left half of the monitor displays information correctly but right half has pink background with a continuous black line in the centre of the screen.

                6. Remove the two flex-cables and clean the contacts (dirt found) with alcohol.

                7. Power on and the monitor is in working condition.

                Once again, thanks all you for the important information.

                Have a nice weekend...Yong Seng
                Congratulations, and welcome to Badcaps.Net!
                There are 10 kind of people in this world: those that understand binary, and those who don't.
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                Comment


                  Re: Fix for Benq FP737s 17" (Q7T3)

                  Hey guys.

                  Got all my monitors working except one, which virtually burst into flames.

                  The good news is that the LCD and the little VGA board still work.

                  Has anyone else tried to manually power this up? I intend to use the screen as a light weight portable screen backlit by LEDs and powered by batteries (if possible)

                  Could someone try this and if it works, could they do a diagram of the VGA board and point out which pins require what voltages, etc?

                  On the schematic, it has BLT_ON and BOLT_ADJ which I assume is the backlight, PW_DOWN (no idea), Volume On/off and volume (not used), GND, P12V, P3.3v, +3.3v, and +5v

                  What's the difference between P3.3v and +3.3v?
                  Last edited by enterthehatrix; 07-10-2009, 03:42 AM.

                  Comment


                    Re: Fix for Benq FP737s 17" (Q7T3)

                    Hi all,

                    Go the parts from ebay (Actually bought 2 sets), replaced all 7 parts.
                    Before it was completely dead, now with the new parts, it actually shows benq logo, or destop image, but just for 2 seconds and then nothing. Any idea?

                    I kind of gave up, so if anybody from Australia is interested in buying the parts, or the screen for further part such as casing etc...I suppose the screen is still good...
                    Anyways let me know.

                    Comment


                      Re: Fix for Benq FP737s 17" (Q7T3)

                      Originally posted by Caloute
                      Hi all,

                      Go the parts from ebay (Actually bought 2 sets), replaced all 7 parts.
                      Before it was completely dead, now with the new parts, it actually shows benq logo, or destop image, but just for 2 seconds and then nothing. Any idea?

                      I kind of gave up, so if anybody from Australia is interested in buying the parts, or the screen for further part such as casing etc...I suppose the screen is still good...
                      Anyways let me know.
                      Resolder the transformers and other common solder points (see all the thread). You'll be fine.
                      There are 10 kind of people in this world: those that understand binary, and those who don't.
                      • ASUS ROG Maximus IX Code
                      • Intel Core i5-7600K 3.8GHz
                      • 16gb GSKILL TridentZ RGB DDR4-3200
                      • 1 M2 SSD + 2 WD Blue 1TB (Mirrored)
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                      • GeForce GT1050
                        2 x Acer KA240H + 1 Vewsonic VP2130 21 (a cap replacement job )

                      Comment


                        Re: Fix for Benq FP737s 17" (Q7T3)

                        LOOK people! 9 times out of 10, Cold solder joints DO exist on the board. Looky what I found on mine! BE SURE TO REMELT OR (better yet) RESOLDER THE TRANSFORMERS!!!

                        btw, this is from a Dell E172FP / E172FPb
                        Attached Files
                        Last edited by fety; 08-07-2009, 02:27 AM.

                        Comment


                          Re: Fix for Benq FP737s 17" (Q7T3)

                          Well CRAP!! It didn't work! I got the kit on ebay and replaced all 7 parts and resoldered the transformers as well as resoldered a few other suspiciously lame looking solder joints. Nothing shows up on the screen now, just the power LED blinks about every 1.5 seconds AND I can hear a faint tick sound. Like what HelpQuick experienced... What is this a symptom of? what can I try next? replace all/most of the caps? Btw, I'm not an electrical guru, I just have a A. W. Sperry AMM to work with so don't ask me to test this or that if I'm not capable of doing so. Thanks

                          HEEEEELLLLLLLLP!!!!!!!!

                          Comment


                            Re: Fix for Benq FP737s 17" (Q7T3)

                            Originally posted by fety
                            Well CRAP!! It didn't work! I got the kit on ebay and replaced all 7 parts and resoldered the transformers as well as resoldered a few other suspiciously lame looking solder joints. Nothing shows up on the screen now, just the power LED blinks about every 1.5 seconds AND I can hear a faint tick sound. Like what HelpQuick experienced... What is this a symptom of? what can I try next? replace all/most of the caps? Btw, I'm not an electrical guru, I just have a A. W. Sperry AMM to work with so don't ask me to test this or that if I'm not capable of doing so. Thanks

                            HEEEEELLLLLLLLP!!!!!!!!
                            That ticking sound is a symptom of the power supply shutting down and restarting. Have you checked the transistors you installed?

                            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


                              Re: Fix for Benq FP737s 17" (Q7T3)

                              Originally posted by PlainBill
                              That ticking sound is a symptom of the power supply shutting down and restarting. Have you checked the transistors you installed?

                              PlainBill
                              Check them, how? they're brand new...from the 7 piece kit on eBay. Would they fry instantly? Solder looks good.

                              Comment


                                Re: Fix for Benq FP737s 17" (Q7T3)

                                Originally posted by fety
                                Check them, how? they're brand new...from the 7 piece kit on eBay. Would they fry instantly? Solder looks good.
                                Use an ohmmeter.

                                Yes, they can short instantly if the problem that caused them to short is still present.

                                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


                                  Re: Fix for Benq FP737s 17" (Q7T3)

                                  Hi All,

                                  I got a Benq 17" Q7T3 TFT like you all.
                                  It had it's two 2SC5707 shorted, FU 9024n shorted, 3A fuse open.

                                  So far I have replaced the fet with an IRF9540, wich according to
                                  my suppier is a good replacement.

                                  I replaced the two broken 2SC5707's with TIP132. I know this is not good, however it was the only thing I could get my hands on...
                                  Resoldered the transformers, resoldered other suspicious joints too.

                                  Powering the TFT up:
                                  Well: it did not go up in smoke

                                  Backlight works, and it shows the "Benq" logo. Went out after 4 seconds.
                                  I Tried that again:
                                  So I connected a PC and it showed the window desktop just fine, but again, the monitor shutted itself down after a few seconds (faster every time)

                                  Things tried with data cable disconnected:
                                  - Connected CCFL lamps to inverter 1 (the good one)
                                  ---> Screen is lit, shuts down after a few seconds
                                  - Connected CCFL lamps to inverter 2 (the repaired one)
                                  ---> Screen is lit, shuts down after a few seconds
                                  - Connected CCFL lamps to inverter 1 & 2
                                  ---> Screen is lit, shuts down after a few seconds

                                  However: when feeling at the TIP 132 transistors they get HOT.
                                  I can barley touch them with my hands.

                                  ....while the two remaining 2SC5707 are actually cool running.
                                  Is the TFT shutting down because of the improper transistors used, or is there another fault I can check that overheats the TIP 132's

                                  Should I swap the two remaining good 2SC5707 with TIP132 too just to see that they overheat too or not?

                                  Greetings and thank you in advance!
                                  S.
                                  Last edited by steven.va; 12-02-2009, 11:32 AM.

                                  Comment


                                    Re: Fix for Benq FP737s 17" (Q7T3)

                                    You need to go with 4 of the 2SC5707s or 4 of others, but the TIPs are known to run hot (not recomended)

                                    Comment


                                      Re: Fix for Benq FP737s 17" (Q7T3)

                                      Originally posted by Bobdee
                                      You need to go with 4 of the 2SC5707s or 4 of others, but the TIPs are known to run hot (not recomended)
                                      Could that explain the shutting down of the inverter after 4-5 seconds?

                                      Greetings,
                                      S.

                                      Comment


                                        Re: Fix for Benq FP737s 17" (Q7T3)

                                        Yes in one
                                        You need to go 4 of same type
                                        Easy and quick to get 2SC5707s on ebay

                                        Comment


                                          Re: Fix for Benq FP737s 17" (Q7T3)

                                          My 2SC5707s arrived. Soldered them in, and my Benq FP731 works!

                                          I did resolder the connections to transformers.

                                          Greetings,
                                          Steven

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