Viewsonic VE710b Power on black screen

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  • Guti904
    Senior Member
    • Jun 2012
    • 71
    • Argentina

    #41
    Re: Viewsonic VE710b Power on black screen

    Originally posted by Rtech
    CN6 goes to the Logic Board, is there any markings on the bottom of the Board to tell you what is supposed to be on each pin ?? with only six pins, it is likely that they are 2 x ground, maybe 2 x 5/12volts,1 x Dim/adjust, and 1 x BLON/ENA,Using the latter and ground you can apply approx 3v,maybe from a battery,Power the Power board ONLY,and have lamps plugged in, and if the Board is 100% the lamps will light.
    I plugged the power board only, with the lamps and after plugged in the power cord the lamps seems to power on but only blinks at same time the strange sounds comes out (http://www.youtube.com/watch?v=CHpzS...ature=youtu.be)

    The 6 ouput pins may measure 5 or 12v without having the main board connected?? Or it needed the power on signal to start working and deliver the voltage?

    Comment

    • Guti904
      Senior Member
      • Jun 2012
      • 71
      • Argentina

      #42
      Re: Viewsonic VE710b Power on black screen

      Can I try to replace the 470uF capacitors although not inflated?? Can these cause the problem?

      Comment

      • selldoor
        Slow Learner
        • Dec 2010
        • 7870

        #43
        Re: Viewsonic VE710b Power on black screen

        yes replace all the caps you want.
        Originally posted by Guti904
        Or it needed the power on signal to start working and deliver the voltage?
        That is usually what happens - you usually need the main board connected
        to provide the power on signal.

        Any luck getting the spare lights/panel from the office?.

        Are you saying the backlight flash cycles that is you press power on
        the back lights flash twice then go off for 4-5 seconds then flash twice then off for 4-5 seconds then flash twice and again and again
        Please upload pictures using attachment function when ask for help on the repair
        http://www.badcaps.net/forum/showthread.php?t=39740

        Comment

        • selldoor
          Slow Learner
          • Dec 2010
          • 7870

          #44
          Re: Viewsonic VE710b Power on black screen

          Can you get a picture of the board attached to the panel - take care as this is
          sometimes easy to damage if permanently attached
          Please upload pictures using attachment function when ask for help on the repair
          http://www.badcaps.net/forum/showthread.php?t=39740

          Comment

          • Rtech
            Badcaps Legend
            • Jul 2010
            • 1095

            #45
            Re: Viewsonic VE710b Power on black screen

            "The 6 ouput pins may measure 5 or 12v without having the main board connected?? Or it needed the power on signal to start working and deliver the voltage?"

            They will just flash like that, you need the Power On signal OR as I Suggested (3v) as that is approx what the Power On signal is.and if all is well then the lights will stay on.

            Comment

            • Guti904
              Senior Member
              • Jun 2012
              • 71
              • Argentina

              #46
              Re: Viewsonic VE710b Power on black screen

              Originally posted by selldoor
              yes replace all the caps you want.


              That is usually what happens - you usually need the main board connected
              to provide the power on signal.

              Any luck getting the spare lights/panel from the office?.

              Are you saying the backlight flash cycles that is you press power on
              the back lights flash twice then go off for 4-5 seconds then flash twice then off for 4-5 seconds then flash twice and again and again
              I'm just taking out the backlights from the broken monitor, but it's a 17'' monitor and the other it's a square 17''... so, i don´t know if the bulbs can be replaced, but will works for testing..

              Sorry to all for my bad english... i've learned by myself...

              Comment

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #47
                Re: Viewsonic VE710b Power on black screen

                You can use those lamps for testing purpose, I even use this for tersting:
                https://www.badcaps.net/forum/showthread.php?t=19987
                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

                • Guti904
                  Senior Member
                  • Jun 2012
                  • 71
                  • Argentina

                  #48
                  Re: Viewsonic VE710b Power on black screen

                  Originally posted by budm
                  You can use those lamps for testing purpose, I even use this for tersting:
                  https://www.badcaps.net/forum/showthread.php?t=19987
                  Excelent! I tried a minute ago the power and main board with the button panel and the other bulb and now I can see the light! It blinks two times (power on and power off) and repeats this after 5 seconds... So, i think the inverter is the problem. I will change the 470 caps and try again... or what do you recommend to do?

                  Comment

                  • selldoor
                    Slow Learner
                    • Dec 2010
                    • 7870

                    #49
                    Re: Viewsonic VE710b Power on black screen

                    I dont see that is any better?

                    This is the test you should do
                    You have a LCD with 4 CCFLs (numbered 1 to 4) and a spare.

                    Pay ATTENTION as there is a VERY HIGH VOLTAGE (600V to 1000V)! As a safety precaution, it might help to have someone around when you are doing this if something screws up.

                    a) TURN POWER OFF and unplug the monitor and wait 1 minute
                    b) disconnect CCFL #1 and plug in spare CCFL into spot #1
                    c) plug in monitor and turn monitor on - note if "2 seconds to black" occurs
                    d) TURN POWER OFF and unplug the monitor and wait 1 minute
                    e) reconnect CCFL #1 and disconnect CCFL #2 and plug in spare CCFL into spot #2
                    f) plug in monitor and turn monitor on - note if "2 seconds to black" occurs
                    g) TURN POWER OFF and unplug the monitor and wait 1 minute
                    h) reconnect CCFL #2 and disconnect CCFL #3 and plug in spare CCFL into spot #3
                    i) plug in monitor and turn monitor on - note if "2 seconds to black" occurs
                    j) TURN POWER OFF and unplug the monitor and wait 1 minute
                    k) reconnect CCFL #3 and disconnect CCFL #4 and plug in spare CCFL into spot #4
                    l) plug in monitor and turn monitor on - note if "2 seconds to black" occurs

                    If you have a bad CCFL, one of the tests above should show you which one. If you still have "2 seconds to black", then we can assume it is not due to a bad CCFL.
                    Please upload pictures using attachment function when ask for help on the repair
                    http://www.badcaps.net/forum/showthread.php?t=39740

                    Comment

                    • Guti904
                      Senior Member
                      • Jun 2012
                      • 71
                      • Argentina

                      #50
                      Re: Viewsonic VE710b Power on black screen

                      I changed the 2 470uF caps... and nothing... the probe lamp blinks two times in one second and power off... after 5 seconds the sequence repeats... I like the inverter cannot hold the lamp on... so, my question is, what ouput I must to test to see if the inverter is working ok? (the caps are new, the transformers are ok...).

                      Comment

                      • Guti904
                        Senior Member
                        • Jun 2012
                        • 71
                        • Argentina

                        #51
                        Re: Viewsonic VE710b Power on black screen

                        If I connect the lamp in 1 (see pic) the lamp won't turn on (but I can year the "tick" noise). Now, if I connect the lamp in 2 (see pic) the lamp blink 2 times and after 5 secs repeats the sequence.

                        The "tick" sound seems to come out from the trfrms marked with blue square (see pic).

                        What reading must be ok on those small transformers?
                        Attached Files
                        Last edited by Guti904; 06-25-2012, 12:47 PM.

                        Comment

                        • Guti904
                          Senior Member
                          • Jun 2012
                          • 71
                          • Argentina

                          #52
                          Re: Viewsonic VE710b Power on black screen

                          Here's a video to see the fail. (Sorry the quality i didn´t bring my camera at work!)

                          http://www.youtube.com/watch?v=kRSo_...ature=youtu.be

                          Whe the lamp blinks, also blinks the power on led...

                          Comment

                          • selldoor
                            Slow Learner
                            • Dec 2010
                            • 7870

                            #53
                            Re: Viewsonic VE710b Power on black screen

                            Ok -I dont think you understand the test - and I cant say it in Spanish.
                            I will stay online and take you through it
                            To do the test you HAVE to have 4 lamps connected.
                            First -Connect up all 4 that are in the panel.
                            Unplug 1 and instead plug in (connect) the test bulb
                            Advise what happens.
                            Please upload pictures using attachment function when ask for help on the repair
                            http://www.badcaps.net/forum/showthread.php?t=39740

                            Comment

                            • Guti904
                              Senior Member
                              • Jun 2012
                              • 71
                              • Argentina

                              #54
                              Re: Viewsonic VE710b Power on black screen

                              Originally posted by selldoor
                              Ok -I dont think you understand the test - and I cant say it in Spanish.
                              I will stay online and take you through it
                              To do the test you HAVE to have 4 lamps connected.
                              First -Connect up all 4 that are in the panel.
                              Unplug 1 and instead plug in (connect) the test bulb
                              Advise what happens.
                              selldoor, I understand the test, and its always the same behaviour, if I connect the original lamp or the spare lamp, in section 1 (see last posted pic) wont turn on (in CCFL #1 or CCFL #2), and blinks on CCFL #3 and CCFL #4. Have you seen the video? is clearly visible (despite the poor quality) the problem. The lamps (originals and spare) have the same behavior (i think are ok).

                              Comment

                              • selldoor
                                Slow Learner
                                • Dec 2010
                                • 7870

                                #55
                                Re: Viewsonic VE710b Power on black screen

                                I have seen the video there are not 4 lamps plugged in?
                                Please upload pictures using attachment function when ask for help on the repair
                                http://www.badcaps.net/forum/showthread.php?t=39740

                                Comment

                                • Rtech
                                  Badcaps Legend
                                  • Jul 2010
                                  • 1095

                                  #56
                                  Re: Viewsonic VE710b Power on black screen

                                  Originally posted by Rtech
                                  Perhaps we need to go back to basics here ! When you switch on the Monitor, I assume the Power Led comes on ?? then when you switch the Computer on and apply a signal, what happens to the Led ?? eg recognises the signal?, therefore changes colour ?, and stays that way?, or flashes all the time etc etc?. According to the resistance readings the Inverter tfmrs are OK.Outputs of 5v and 12v seem to be normal.I note this is the standard Royer type setup, so doubt,based on the symptoms,must be considered reference the timing caps and associated transistors, and of course the Backlights themselves.This really does highlight the importance of having some test Backlights,and unless these can be eliminated and/or confirmed as the problem,then,you are now going to have to test all the Royer components,and hope that they indicate where you go next.
                                  Timing caps and transistors need testing as advised earlier

                                  Comment

                                  • Guti904
                                    Senior Member
                                    • Jun 2012
                                    • 71
                                    • Argentina

                                    #57
                                    Re: Viewsonic VE710b Power on black screen

                                    Originally posted by selldoor
                                    I have seen the video there are not 4 lamps plugged in?
                                    The video was shooted before pluggin the 4 lamps... but i've test it as you indicated. Have you heard the "tick" sound from the board??

                                    The backlights were discarded because the behavior is the same using the spare backlights...

                                    Comment

                                    • selldoor
                                      Slow Learner
                                      • Dec 2010
                                      • 7870

                                      #58
                                      Re: Viewsonic VE710b Power on black screen

                                      I am still not convinced.

                                      See pictures attached - have you done these 4 tests and you get the same result each time.
                                      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

                                      • Guti904
                                        Senior Member
                                        • Jun 2012
                                        • 71
                                        • Argentina

                                        #59
                                        Re: Viewsonic VE710b Power on black screen

                                        Originally posted by selldoor
                                        I am still not convinced.

                                        See pictures attached - have you done these 4 tests and you get the same result each time.
                                        I will try it when I arrive home. But if I'm tried two spare lamps (without the others connected) makes any difference interleave the spare lamps with the originals? If I tried the spare lamps individually in each CCFL and the result is the same, we could not assure the lamps are ok and that the problem is the inverter or something in the power board?

                                        Comment

                                        • selldoor
                                          Slow Learner
                                          • Dec 2010
                                          • 7870

                                          #60
                                          Re: Viewsonic VE710b Power on black screen

                                          Debe tener 4 lámparas conectadas buenos para hacer la prueba
                                          Please upload pictures using attachment function when ask for help on the repair
                                          http://www.badcaps.net/forum/showthread.php?t=39740

                                          Comment

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