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    ViewSonic VX2260WM not working

    Hello everyone,

    I have a ViewSonic VX2260WM monitor which stopped working months back, the power light blinks, quickly shutting off again and nothing else happens. As the PSU caps are a common problem with these things I've taken the board out, but there doesn't appear to be anything wrong with it, at least not visually. Have only a basic understanding of electronics so don't know how to test it.

    The power here seams to be good at killing things, I've had several desktop power supplies fail on me also.
    Attached Files

    #2
    Re: ViewSonic VX2260WM not working

    Hi - welcome to the forum. I can see that there are suscon caps on this board which is not a good start - are they all suscon if not what other makes.
    Do you have a multimeter?
    If so and while it is disconnected can you test the inverter transformer. Meter set on ohms 2000 test S1 to S2 and S3 to S4. Post the results.
    Attached Files
    Last edited by selldoor; 06-08-2012, 06:40 AM.
    Please upload pictures using attachment function when ask for help on the repair
    http://www.badcaps.net/forum/showthread.php?t=39740

    Comment


      #3
      Re: ViewSonic VX2260WM not working

      Hi selldoor, the caps are as follows:

      su'scon 2x270uf@50v, 1x47uf@25v, 2x220uf@25v
      samxon 3x680uf@25v
      The make/rating of the big cap is covered by the glue.

      Yes I have a multimeter, the transformer shows 0.775 and 0.780 for those pins, not sure of it's orientation.

      Thanks for your help.

      Comment


        #4
        Re: ViewSonic VX2260WM not working

        Ok Ill take that as being 775 ohms and 780 ohms.Which is good.

        With it all connected and on, what voltages do you get on the power supply out.
        Use black probe on ground screw and work down the connector with the red probe.
        Post as
        Pin 1 5v actual 4.9
        Pin 2 5v actual 5.1 etc etc.
        Care although these are low voltages part of the board could be at 220-400 volts.

        Do you have any spare ccfls or another panel (even a broken one might do.)
        Last edited by selldoor; 06-08-2012, 08:10 AM. Reason: added with red probe
        Please upload pictures using attachment function when ask for help on the repair
        http://www.badcaps.net/forum/showthread.php?t=39740

        Comment


          #5
          Re: ViewSonic VX2260WM not working

          Power supply voltages are:

          Pin 1 5v actual 4.2v[*]
          Pin 2 5v actual 4.2v[*]
          Pin 3 5v actual 4.2v[*]
          Pin 4 5v actual 4.2v[*]
          Pin 5 ground
          Pin 6 ground
          pin 7 on/off actual floats between 0.8v and 0v
          pin 8 brightness actual floats between 0.8v and 0v
          [*] starts at this voltage when the monitors power on indicator light flashes then slowly decreases to 0v over a few seconds until the light flashes again.

          The power light flashes while the monitor is plugged in and does not respond to the power on button - it just keeps flashing untill the power is disconnected. Under normal conditions the power indicator light stays on continually.

          Unfortunately I do not have any CCFL's or dead monitors around.
          Last edited by robehickman; 06-08-2012, 09:35 AM.

          Comment


            #6
            Re: ViewSonic VX2260WM not working

            Ok at least there are some voltages. Can you recall how the monitor went off. Did it just not turn on one day or did it deteriorate over time. Can you turn on in a darkened room to see if there is any flash at all from the backlights. Do you have soldering equipment and can you use it? Do you have any capacitors or a local source. We usually advise the use of panasonic fm caps if you can get them. We usually say to leave the BIG cap unless it shows any bulging or damage.

            Can you carefully check the voltage across the legs of the big cap. All connected up
            meter on 600vDC black probe on negative leg and red on the other leg.
            Do not hold probes too near the ends voltage will be 220 to 400 volts.
            Please upload pictures using attachment function when ask for help on the repair
            http://www.badcaps.net/forum/showthread.php?t=39740

            Comment


              #7
              Re: ViewSonic VX2260WM not working

              From what I remember the monitor stopped working one day with the power light flashing, unplugged it and it worked fine the following day until it was turned off. It hasn't worked again since. I can't see anything from the back light at all.

              The house RCD frequently trips whenever its raining or there are high winds, it may have failed after this but I can't remember for sure. I've had a computer PSU fail after it tripped, and the dishwasher's motor run cap failed recently after an RCD trip. Though those could just be coincidences.

              Yes I have soldering equipment and can do through hole soldering, however I have no capacitors on hand and have no idea where to source components. I'm in Chepstow if anyone has any suggestions, physical shops or on-line.

              The voltage across the big cap is 320v.

              Comment


                #8
                Re: ViewSonic VX2260WM not working

                4.2V for the logic is too low. There should be 18~20VdC power supply also, this 5 and 20v are always on power supply. The 680uF 25V is the filter caps for the inverter circuit and it should be present.
                Straight shot pictures of the board both top and bottom?
                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


                  #9
                  Re: ViewSonic VX2260WM not working

                  The 8 connections listed previously are the only connections between the power board and logic board. Here's some more pictures.
                  Attached Files

                  Comment


                    #10
                    Re: ViewSonic VX2260WM not working

                    Hurrah cavalry has landed, wondered where everyone was. Anyway I have a number of suggestions for purchases but suggest waiting to see what other ideas emerge. You dont have many options - cant see anywhere in Gwent.

                    Anyway can you have a look at the ringed item in the attached it is a voltage regulator. Question is is it burnt. If so can you read any numbers on it and can you also get the part number of the other one near to it.

                    I will also add a list of suggested caps from one seller
                    Attached Files
                    Please upload pictures using attachment function when ask for help on the repair
                    http://www.badcaps.net/forum/showthread.php?t=39740

                    Comment


                      #11
                      Re: ViewSonic VX2260WM not working

                      Also there are 2 orange fuses on the power board near the connector to the main board
                      can you test them. Power off Meter on 200 ohms one probe on each end of fuse.
                      post result as F802 = ohms F80x = ohms should read the same as holding the probes together.
                      Please upload pictures using attachment function when ask for help on the repair
                      http://www.badcaps.net/forum/showthread.php?t=39740

                      Comment


                        #12
                        Re: ViewSonic VX2260WM not working

                        Please see the attached pictures, you can power up the board without the logic board connected, but do connect the lamps connectors. Please take a reading of that DC filter cap for the Inverter circuits, you can read it right on the two pins of the cap. I need to see if the voltage is off by the same percentage as the 5V supply.
                        Also, what is the value of the two caps in red circle on the right of the picture?
                        Attached Files
                        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


                          #13
                          Re: ViewSonic VX2260WM not working

                          @selldoor, they MOSFET for driving the inverter transformer, it is a half-bridge drive setup.
                          The two PICO fuses are for the USB hub and the logic board, since he is getting 4.2Vdc on pin 1~4, the fuses are OK.
                          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


                            #14
                            Re: ViewSonic VX2260WM not working

                            whoops! - thanks budm. I just see a fuse and check them. As you will have gathered I
                            dont know much about circuitry, but I am trying to learn.
                            Last edited by selldoor; 06-08-2012, 01:46 PM.
                            Please upload pictures using attachment function when ask for help on the repair
                            http://www.badcaps.net/forum/showthread.php?t=39740

                            Comment


                              #15
                              Re: ViewSonic VX2260WM not working

                              I am still learning everyday myself.
                              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


                                #16
                                Re: ViewSonic VX2260WM not working

                                @selldoor the ringed item appears undamaged and has markings, however I cannot read them, the fuses are good.

                                @budm the voltage of that capacitor fluctuates between 25 and 30 volts. They are both 270uf@50v.

                                The 4.2v reading is only approximate and does fluctuate as mentioned above. It may start higher than this but my multimeter does not update its display that quickly, so it could drop in the interim.

                                I did power the board up without the logic board earlier(with the lamps connected) and it it tripped the house's RCD within a second or two, don't want to risk doing that again at this time.
                                Last edited by robehickman; 06-08-2012, 02:55 PM.

                                Comment


                                  #17
                                  Re: ViewSonic VX2260WM not working

                                  Very odd. The voltage is too low on the 5V output and would seem a bit high on the inverter output.

                                  Comment


                                    #18
                                    Re: ViewSonic VX2260WM not working

                                    That does not sound right at all, 25~30V for 22" LCD backlights inverter circuits, and it also trips the RCD when the board is running by itself (I do this all the time), something is not setup right some where.
                                    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


                                      #19
                                      Re: ViewSonic VX2260WM not working

                                      I think you should have your electrics checked by a qualified electrician - RCDs are safety devices and should not just trip randomly! You could have a loose or intermittent ground somewhere. I have only ever once tripped the RCD, by touching ground and the heatsink of a power supply at the same time. It's painful and I will avoid doing it next time...!
                                      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


                                        #20
                                        Re: ViewSonic VX2260WM not working

                                        Thanks for the comments, what (in your opinion) is the probability that changing the caps will fix this, vs it being some other issue.

                                        Comment

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