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    #41
    Re: Hanspree HSG1075

    the fourth pin that you described on Q2 gives me a reading of .02 on the meter.
    This was taken with my meter on 20V DCV

    Comment


      #42
      Re: Hanspree HSG1075

      OK, so my diagnosis would be that MOSFET Q2. Can you read off the part code written on it?
      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


        #43
        Re: Hanspree HSG1075

        Please upload pictures using attachment function when ask for help on the repair
        http://www.badcaps.net/forum/showthread.php?t=39740

        Comment


          #44
          Re: Hanspree HSG1075

          it says PAGFU ?09 443582

          Comment


            #45
            Re: Hanspree HSG1075

            Originally posted by rhodesjo View Post
            it says PAGFU ?09 443582
            I think you will find it says 4435BZ as per previous post
            Please upload pictures using attachment function when ask for help on the repair
            http://www.badcaps.net/forum/showthread.php?t=39740

            Comment


              #46
              Re: Hanspree HSG1075

              OK, just check the voltage on pin 1, 2 or 3 (doesn't matter which they are all connected to each other.)

              Another thing you could do is jumper across from source to drain... this will bypass the FET and leave the t-con power on always. It would use a little more power in standby, but it is still likely to work fine.
              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


                #47
                Re: Hanspree HSG1075

                4435BZ thanks selldoor, my eyes arent the greatest lol
                tom, your suggestion about bypassing the FET, source to drain, sounds great, I am willing to attempt this but I may need a little more clarification on how to do that. you guys have been amazingly helpful, I'm very impressed by this forum.

                Comment


                  #48
                  Re: Hanspree HSG1075

                  First please check the voltage on the source 1/2/3 pins to make sure there isn't a broken input component (the cap I had you check is just the nearby 12V supply, not necessarily the input to the device.)

                  If that's near enough to 12V then just solder a wire (capable of about 3A) from the three source pins to the four drain pins (5,6,7,8.)
                  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


                    #49
                    Re: Hanspree HSG1075

                    If you click on the link post43 it will download a datasheet for the mosfet.
                    In that there is a picture and diagram of it showing pin 4 is gate , pins 1 to 3 (Source) are all joined and pins 5-8 are all joined (Drain) So you need to solder a piece of wire across from 1-3 to 5 to 8

                    EDIT
                    As Toms says
                    Last edited by selldoor; 12-28-2012, 04:59 PM.
                    Please upload pictures using attachment function when ask for help on the repair
                    http://www.badcaps.net/forum/showthread.php?t=39740

                    Comment


                      #50
                      Re: Hanspree HSG1075

                      thank you guys so much, I will update you after I try that once I return home again after the new year

                      Comment


                        #51
                        Re: Hanspree HSG1075

                        hey guys, after a long holiday and getting back to work, I finally have what I need to perform this job. I thought before I apply the solder that maybe I should post what my interpretation of your instructions has produced. In this photo, I have laid out the customized, cut, yellow insulated wire onto the circuit board in the position I believe it needs to be, connecting pins 1-3 & 5-8. If this looks good I will solder it into place and test the TV!
                        Attached Files

                        Comment


                          #52
                          Re: Hanspree HSG1075

                          That should work great.
                          See if it works!
                          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


                            #53
                            Re: Hanspree HSG1075

                            Disregard my post, found the confusion of how the lytics caps are marked for negative/positive. Tom shows me the better pictures of the board.
                            Last edited by budm; 01-03-2013, 06:31 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


                              #54
                              Re: Hanspree HSG1075

                              The part is a P-channel MOSFET. In this application it is used because it is really simple to switch, compared to N-channel. I use P-channel high side switches all the time in my designs, they are the greatest thing since sliced bread!

                              To turn a P-channel on you just need to make the gate more negative than the source. So if the source is +12V or +5V, simply grounding the gate will provide -12V or -5V Vgs, which will enhance the channel and make the FET conduct.

                              An N-channel would require a supply like +20V to turn on a 12V supply.

                              The inductor is part of a pi filter along with the capacitor. And as the capacitor is configured ground n egative, output to positive, the output must be positive. Or the cap wouldn't last very long!

                              Since it is a single FET and no diode it cannot be a buck/boost/buck-boost type converter and must be a simple switch. See below:



                              If we look at the switching converter in the background you have highlighted we can see that the input comes from the bottom through a ferrite bead into the input of the IC, there is a small decoupling cap (normally a little larger? might be something on the bottom, though)

                              The buck diode with the inductor is configured as a positive buck converter. The output capacitor has the negative terminal connected to ground so the output must be positive. One example -- uses external FET, the chip in picture has internal one:

                              Last edited by tom66; 01-03-2013, 06:02 PM.
                              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


                                #55
                                Re: Hanspree HSG1075

                                Disregard my post, found the confusion on the way the lytics caps are marked on the PCB. Tom shows me better pictures of the board.
                                Last edited by budm; 01-03-2013, 06:25 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


                                  #56
                                  Re: Hanspree HSG1075

                                  No, it's not. It's hard to see in the image but this other shot makes it clear.
                                  Attached Files
                                  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


                                    #57
                                    Re: Hanspree HSG1075

                                    The resistors just go from the switched T-con power to ground. I guess they are some kind of load to discharge the capacitor, I do not know why -- perhaps the T-con misbehaves on switch off and needs to turn off quicker.
                                    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


                                      #58
                                      Re: Hanspree HSG1075

                                      I see what the confusion is now in the picture, the white bar on the pcb footprint usually represent negative to mach the bar on the cap, from the picture of the cap, the white bar on the board in this case is positive, very bad way of making footprint.
                                      I see why I thought that is negative leg of the cap due to white bar on the board. If you did not show the picture in post 56 I would not have known, thanks.
                                      Last edited by budm; 01-03-2013, 06:22 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


                                        #59
                                        Re: Hanspree HSG1075

                                        Here is the reverse engineered schematic of that portion.

                                        We have seen reverse colouring on Asus motherboards too. Why? I have no idea!
                                        Attached Files
                                        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


                                          #60
                                          Re: Hanspree HSG1075

                                          If I got the polarity base on the pictures right, that would not bring up my question in the first place, if some one remove the caps and come back later on to install the new caps, it would be really bad news unless there are '+' on the board also.
                                          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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