Could use some help, trying to fix HP 1940 LCD

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  • playman
    Badcaps Veteran
    • Jan 2011
    • 252

    #21
    Re: Could use some help, trying to fix HP 1940 LCD

    You worked too hard. Pins 1 and 3 are connected internally. For anyone else doing this, simply test 2-3, 2-4, and 3-4. This test is simply to determine if there is a short.
    allright i'll try to remember that.
    So if I understood you right, #1 is broken, and therefore I should replace all 4 c5707?
    The J598 goes back into the board?

    Comment

    • playman
      Badcaps Veteran
      • Jan 2011
      • 252

      #22
      Re: Could use some help, trying to fix HP 1940 LCD

      I wont be able to reply again until on monday, so just blast your thoughts at me

      P.S. I wish that the edit button didint have time out on it.

      Comment

      • retiredcaps
        Badcaps Legend
        • Apr 2010
        • 9271

        #23
        Re: Could use some help, trying to fix HP 1940 LCD

        Originally posted by playman
        So if I understood you right, #1 is broken, and therefore I should replace all 4 c5707?
        If Q808 is bad, then Q809 is its companion. Look at your board and you will see they work in pairs. So if Q808 is bad, Q809 should be replaced as well.
        --- begin sig file ---

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        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

        • playman
          Badcaps Veteran
          • Jan 2011
          • 252

          #24
          Re: Could use some help, trying to fix HP 1940 LCD

          If Q808 is bad, then Q809 is its companion. Look at your board and you will see they work in pairs. So if Q808 is bad, Q809 should be replaced as well.
          yeah ofcourse how silly of me
          allright they have all been replaced now.
          Is there anything else I should do or test before I screew it back in and power it on?

          Comment

          • playman
            Badcaps Veteran
            • Jan 2011
            • 252

            #25
            Re: Could use some help, trying to fix HP 1940 LCD

            Update!

            Well I just repacked it and plugged it in for testing, with 2 fingers crossed and other
            hand ready on the socket

            So now i'm just going to fully assemble it and leave it on for awhile, and see if it will continue to work.

            Now I should be able to fix the rest of them.

            thanks every one for inputs and help

            With regards
            Johannes

            Comment

            • rqbwins
              New Member
              • Mar 2012
              • 8
              • romania

              #26
              Re: Could use some help, trying to fix HP 1940 LCD

              Hello.Can Anybody tell me what kind of transistor is in q885.Becouse mine was so burned that I could not read the inscription on it.Thank you in advance for your help.
              Attached Files
              Last edited by rqbwins; 04-02-2012, 07:04 AM.

              Comment

              • retiredcaps
                Badcaps Legend
                • Apr 2010
                • 9271

                #27
                Re: Could use some help, trying to fix HP 1940 LCD

                Originally posted by rqbwins
                Can Anybody tell me what kind of transistor is in q885.
                It is might be fu9024 (the same one as to the right of T802 and left of the big cap).

                These Benq boards are infamous for having bad solder joints on the inverter transformers, shorted c5707 transistors, shorted fu9024 mosfets, and blown picofuse.

                See

                https://www.badcaps.net/forum/showthread.php?t=8598
                --- 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

                • Jasgriff
                  Badcaps Veteran
                  • Feb 2012
                  • 578
                  • UK

                  #28
                  Re: Could use some help, trying to fix HP 1940 LCD

                  Already answered
                  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

                  • rqbwins
                    New Member
                    • Mar 2012
                    • 8
                    • romania

                    #29
                    Re: Could use some help, trying to fix HP 1940 LCD

                    Thank you for this quick reply.I would like to bother you guys with one more question.Which of the following transistor should I buy?

                    1:IRFU9024 IR CI -ROHS-
                    2:IRFU9024NPBF TRANZISTOR MOSFET,P I-PAK -55V-11A
                    3:IRFU9024N IR HEXFET(R) POWER MOSFET 55V/11A38W -ROHS-

                    Comment

                    • selldoor
                      Slow Learner
                      • Dec 2010
                      • 7870

                      #30
                      Re: Could use some help, trying to fix HP 1940 LCD

                      They will probably all work the U9024 is the important bit.
                      Where are you looking at them - digikey/mouser/elsewhere.
                      If the first two there will be data sheets which will give you an idea of the differences - it is usual package/ size/ manufacture or even just local product identification.
                      You need to check that you get one the same size as you have.
                      You need to get the correct mounting - surface or through hole

                      2:IRFU9024NPBF TRANZISTOR MOSFET,P I-PAK -55V-11A
                      For example IRFU9024N is the standard the PBF means it is lead free
                      I-pak is the package style

                      If you look here you can find the package style you need
                      http://www.irf.com/package/pkhexfet.html
                      Please upload pictures using attachment function when ask for help on the repair
                      http://www.badcaps.net/forum/showthread.php?t=39740

                      Comment

                      • jetadm123
                        Badcaps Legend
                        • Feb 2010
                        • 2169

                        #31
                        Re: Could use some help, trying to fix HP 1940 LCD

                        Originally posted by rqbwins
                        Thank you for this quick reply.I would like to bother you guys with one more question.Which of the following transistor should I buy?

                        1:IRFU9024 IR CI -ROHS-
                        2:IRFU9024NPBF TRANZISTOR MOSFET,P I-PAK -55V-11A
                        3:IRFU9024N IR HEXFET(R) POWER MOSFET 55V/11A38W -ROHS-
                        You can purchase a repair kit from a Romanian seller on eBay:

                        http://www.ebay.com/itm/REPAIR-KIT-E...item19cebe40e0

                        Comment

                        • rqbwins
                          New Member
                          • Mar 2012
                          • 8
                          • romania

                          #32
                          Re: Could use some help, trying to fix HP 1940 LCD

                          Thank you for your help.I will post tomorrow how it turns out.

                          Comment

                          • rqbwins
                            New Member
                            • Mar 2012
                            • 8
                            • romania

                            #33
                            Re: Could use some help, trying to fix HP 1940 LCD

                            On the back of the panel I have 2 diodes of the same kind.Can someone tell me what kind of diodes are ?
                            I changed the tranzistors and ewerything else but I am having the same problem.
                            One of the diodes from the back seems to be blown.

                            Comment

                            • selldoor
                              Slow Learner
                              • Dec 2010
                              • 7870

                              #34
                              Re: Could use some help, trying to fix HP 1940 LCD

                              Can you post good clear pictures of the front and back of your boards
                              with a close up of the area with the diodes on.
                              Please upload pictures using attachment function when ask for help on the repair
                              http://www.badcaps.net/forum/showthread.php?t=39740

                              Comment

                              • rqbwins
                                New Member
                                • Mar 2012
                                • 8
                                • romania

                                #35
                                Re: Could use some help, trying to fix HP 1940 LCD

                                There it is
                                Attached Files

                                Comment

                                • Nocta
                                  Senior Member
                                  • Mar 2012
                                  • 117
                                  • Argentina

                                  #36
                                  Re: Could use some help, trying to fix HP 1940 LCD

                                  Those seem to be caps for me. The one on the bottom of the board says C819.

                                  Comment

                                  • selldoor
                                    Slow Learner
                                    • Dec 2010
                                    • 7870

                                    #37
                                    Re: Could use some help, trying to fix HP 1940 LCD

                                    Picture is poor in comparison with your earlier ones. Cant even read the board numbers
                                    for the parts. Nevertheless I think thay may be SS24 SMB 40V 2A is that what they look like?.


                                    Please take note about the resoldering of the boards - if you dont do it it could blow all you have
                                    put in.



                                    @Nocta the cap is just below the diode.
                                    Last edited by selldoor; 04-05-2012, 09:35 AM.
                                    Please upload pictures using attachment function when ask for help on the repair
                                    http://www.badcaps.net/forum/showthread.php?t=39740

                                    Comment

                                    • rqbwins
                                      New Member
                                      • Mar 2012
                                      • 8
                                      • romania

                                      #38
                                      Re: Could use some help, trying to fix HP 1940 LCD

                                      Here are the new photos.Hope that you can see better on this pictures
                                      Attached Files

                                      Comment

                                      • selldoor
                                        Slow Learner
                                        • Dec 2010
                                        • 7870

                                        #39
                                        Re: Could use some help, trying to fix HP 1940 LCD

                                        That is a much better picture - still cant read what it says on them perhaps you can and post it. Did you check them - The traces nearby would give me some concern - do they
                                        still conduct?
                                        Please upload pictures using attachment function when ask for help on the repair
                                        http://www.badcaps.net/forum/showthread.php?t=39740

                                        Comment

                                        • jetadm123
                                          Badcaps Legend
                                          • Feb 2010
                                          • 2169

                                          #40
                                          Re: Could use some help, trying to fix HP 1940 LCD

                                          Originally posted by rqbwins
                                          Here are the new photos.Hope that you can see better on this pictures
                                          You never did say what problems you're experiencing. Can you please give us a more detailed description of the problem? Does the power led remain on? Do you get 2 seconds to black? A complete description of the symptoms helps members point out things to check.

                                          Comment

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