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    #81
    Re: 42inch Touch Screen wont power on

    Originally posted by tom66 View Post
    Okay, let's take a different angle of attack. Replace the diode with the new one. Post a picture of the connector going from the PSU to the main board.
    A+B both go to the main board .

    However if you notice before it there is a small heatsinc this contains a 6pin IC chip is this worth testing?
    Attached Files

    Comment

      #82
      Re: 42inch Touch Screen wont power on

      Have you tested the voltages out of that connector?
      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

        #83
        Re: 42inch Touch Screen wont power on

        Originally posted by tom66 View Post
        Have you tested the voltages out of that connector?
        yes see post #16 that is what lead us the check the diodes,

        we have found that the caps are not getting power the diodes test fine, how do i check the transformers or myabe the transistors on the other heatsincs?
        Last edited by epicfatigue; 12-12-2011, 05:32 AM.

        Comment

          #84
          Re: 42inch Touch Screen wont power on

          Originally posted by epicfatigue View Post
          yes see post #16 that is what lead us the check the diodes,

          we have found that the caps are not getting power the diodes test fine, how do i check the transformers or myabe the transistors on the other heatsincs?
          Oh okay. Test the secondary side of the transformer. Every pin should measure short circuit or very close to. However, if the transformer is not working, there is little you can do to get a replacement.
          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

            #85
            Re: 42inch Touch Screen wont power on

            Originally posted by tom66 View Post
            Oh okay. Test the secondary side of the transformer. Every pin should measure short circuit or very close to. However, if the transformer is not working, there is little you can do to get a replacement.
            Okay and if that checks out whats my next step so i can do more then one thing?

            Comment

              #86
              Re: 42inch Touch Screen wont power on

              Originally posted by tom66 View Post
              Have you tested the voltages out of that connector?
              I think a better question/suggestion is

              Have you retested the voltage at the connector with the replacement diode? It is a reasonable suggestion since one component has been changed and could produce new results?

              If it was the same component reused or reinstalled, then I could see no point in retesting.
              Last edited by retiredcaps; 12-12-2011, 04:07 PM.
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                #87
                Re: 42inch Touch Screen wont power on

                Originally posted by retiredcaps View Post
                I think a better question/suggestion is

                Have you retested the voltage at the connector with the replacement diode? It is a reasonable suggestion since one component has been changed and could produce new results?

                If it was the same component reused or reinstalled, then I could see no point in retesting.
                Good point. I am trying to deduce if the primary is switching at all.
                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

                  #88
                  Re: 42inch Touch Screen wont power on

                  Hey all sorry back from holidays and still on them so have some decent time to do testing.

                  All voltages tested the same as they did before from the power points so guessing the diode wasnt the problem.

                  Marked as diagram
                  (1)
                  1-2 .243
                  2-1 ol
                  2-3 ol
                  3-2 .244
                  3-1 ol
                  1-3 ol
                  (2)
                  1-2 .196
                  2-1 ol
                  2-3 ol
                  3-2 .196
                  3-1 ol
                  1-3 ol

                  (3)
                  1-2 .196
                  2-1 ol
                  2-3 ol
                  3-2 .196
                  3-1 ol
                  1-3 ol
                  (4)
                  1-2 .193
                  2-1 ol
                  2-3 ol
                  3-2 .193
                  3-1 ol
                  1-3 ol
                  (5)
                  1-2 .193
                  2-1 ol
                  2-3 ol
                  3-2 .193
                  3-1 ol
                  1-3 ol
                  (6)
                  1-2 .195
                  2-1 ol
                  2-3 ol
                  3-2 .195
                  3-1 ol
                  1-3 ol

                  Retested
                  Attached Files

                  Comment

                    #89
                    Re: 42inch Touch Screen wont power on

                    A) One still unanswered question from post #25.

                    1) See if pin 12 (vcc) is shorted to pin 10 (gnd). Any resistance reading less than 30 ohms suggests it is bad. If yes, I believe that indicates L659 is bad.

                    ====

                    B) With the new diode in now, redo tests 3 and 4 in post #25.

                    ====

                    New test.

                    c) On the biggest yellow transformer (the one above the Powerview logo), there are 17 pins on that transformer.

                    Number them however you like, but upload a picture with your numbering scheme so we know what it looks like. With power off and lcd unplugged measure the resistance and report all readings for the following pin combinations.

                    1-2, 1-3, 1-4, etc, etc, 1-16, 1-17
                    2-3, 2-4, etc, etc 2-17
                    3-4, 3-5, etc, etc, 3-17
                    etc
                    etc
                    14-15, 14-16, 14-17
                    15-16, 15-17,
                    finally
                    16-17

                    We are testing every possible pin combination with the above.

                    If possible, put it into a spreadsheet and export it as a PDF file so it is in a nice grid and we can read everything.

                    What we are looking for here is something obvious like an open winding when it shouldn't be. From the backside, you can tell which pins are supposed to have a low ohms reading (like 0.3).
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                      #90
                      Re: 42inch Touch Screen wont power on

                      Originally posted by epicfatigue View Post
                      All voltages tested the same as they did before from the power points so guessing the diode wasnt the problem.
                      It is not uncommon to have more than 1 problem especially if the TV was subject to a power surge.

                      In the computer lcd world, some Benq boards have multiple problems. Bad caps, bad solder joints, open fuses, bad mosfets and bad transistors ALL can show up in one monitor. I know because I have fixed 5 or 6 of them.
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                        #91
                        Re: 42inch Touch Screen wont power on

                        Originally posted by retiredcaps View Post
                        It is not uncommon to have more than 1 problem especially if the TV was subject to a power surge.

                        In the computer lcd world, some Benq boards have multiple problems. Bad caps, bad solder joints, open fuses, bad mosfets and bad transistors ALL can show up in one monitor. I know because I have fixed 5 or 6 of them.
                        Okay i just pulled everything off the board.

                        I will test both the transformers, i am testing the bridge rec out of circut.

                        I pulled the IC off on the small Heatsinc it is DH18 B DM0465R

                        can i do test 25# out of circut ? it tested okay last time sorry i thought i posted that.

                        Comment

                          #92
                          Re: 42inch Touch Screen wont power on

                          resultrs from transformer 1 (large one)
                          Attached Files

                          Comment

                            #93
                            Re: 42inch Touch Screen wont power on

                            Check your pdf file. The formatting is all screwed up? I can't find 1-2, 1-3, etc.

                            If you can't get it looking correctly in the pdf, then post your xls file.
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                              #94
                              Re: 42inch Touch Screen wont power on

                              Originally posted by epicfatigue View Post
                              I pulled the IC off on the small Heatsinc it is DH18 B DM0465R
                              1) Datasheet is at



                              This is a FET/SMPS. Refer to figure 3 for the pinouts.

                              2) Pin 3 is Vcc and pin 2 is GND. Measure the resistance between these 2 pins. Report the reading.

                              3) According to the datasheet, when Vcc reaches 12 V DC, it starts working. After we tell you to reinstall everything, check Vcc to see if it gets to 12V DC.

                              4) Page 13 has a schematic.
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                                #95
                                Re: 42inch Touch Screen wont power on

                                Originally posted by retiredcaps View Post
                                1) Datasheet is at



                                This is a FET/SMPS. Refer to figure 3 for the pinouts.

                                2) Pin 3 is Vcc and pin 2 is GND. Measure the resistance between these 2 pins. Report the reading.

                                3) According to the datasheet, when Vcc reaches 12 V DC, it starts working. After we tell you to reinstall everything, check Vcc to see if it gets to 12V DC.

                                4) Page 13 has a schematic.
                                .480 M ohms between pins

                                Comment

                                  #96
                                  Re: 42inch Touch Screen wont power on

                                  Originally posted by retiredcaps View Post
                                  Check your pdf file. The formatting is all screwed up? I can't find 1-2, 1-3, etc.

                                  If you can't get it looking correctly in the pdf, then post your xls file.
                                  sorry didnt see that i am just sitting an waiting lol here is the xml
                                  Attached Files

                                  Comment

                                    #97
                                    Re: 42inch Touch Screen wont power on

                                    Still missing a whole bunch of data. See post #89 again for the pattern and compare to your xls file.
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                                      #98
                                      Re: 42inch Touch Screen wont power on

                                      Originally posted by retiredcaps View Post
                                      Still missing a whole bunch of data. See post #89 again for the pattern and compare to your xls file.
                                      sorry mate here we go.

                                      It was very hard to get the reading of resitance it seemed to be very tempermental
                                      Attached Files
                                      Last edited by epicfatigue; 12-30-2011, 04:16 AM.

                                      Comment

                                        #99
                                        Re: 42inch Touch Screen wont power on

                                        Hmm, I think from looking at the hot side data and the picture in post #20, I would have expected continuity between more pins in the primary and tertiary.

                                        I'll see if tom66 and PlainBill concur or not. I could be looking at the wrong transformer too.

                                        You might as well test "in circuit" the yellow transformer below the big one. You don't have to desolder, but we would like to see the same "all pins" combination test.
                                        Last edited by retiredcaps; 12-30-2011, 04:44 AM.
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                                          #100
                                          Re: 42inch Touch Screen wont power on

                                          Originally posted by retiredcaps View Post
                                          Hmm, I think from looking at the hot side data and the picture in post #20, I would have expected continuity between more pins in the primary and tertiary.

                                          I'll see if tom66 and PlainBill concur or not. I could be looking at the wrong transformer too.

                                          You might as well test "in circuit" the yellow transformer below the big one. You don't have to desolder, but we would like to see the same "all pins" combination test.
                                          hey mate here is rear trans testing the one infront of bridge rec anyhow while i am waiting for more instructions.

                                          Should i test the mosfets?
                                          Attached Files

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