Sanyo DP42740 no power

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Agent24
    I see dead caps
    • Oct 2007
    • 4913
    • New Zealand

    #61
    Re: Sanyo DP42740 no power

    Did you compare the two PSUs to be sure they were compatible - at least had the same rails on the same pins etc?
    "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
    -David VanHorn

    Comment

    • triplefour
      Badcaps Legend
      • May 2014
      • 1747
      • USA

      #62
      Re: Sanyo DP42740 no power

      yea they r exactly the same
      Don't fear the repair...

      Comment

      • Agent24
        I see dead caps
        • Oct 2007
        • 4913
        • New Zealand

        #63
        Re: Sanyo DP42740 no power

        I wonder if you disturbed some loose connection when replacing the PSU?
        "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
        -David VanHorn

        Comment

        • triplefour
          Badcaps Legend
          • May 2014
          • 1747
          • USA

          #64
          Re: Sanyo DP42740 no power

          i dunno what could be loose. i will have to wait to tomorrow to look at the tv again
          Don't fear the repair...

          Comment

          • triplefour
            Badcaps Legend
            • May 2014
            • 1747
            • USA

            #65
            Re: Sanyo DP42740 no power

            ok 2 days went by and im looking at the tv again. i left it with the original psu installed. now it powers up and backlight comes on just fine but i just get a blank backlit screen like the TCON is out or the motherboard is not giving the signal. why has the problem jumped from the PSU to the main board now???
            Don't fear the repair...

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #66
              Re: Sanyo DP42740 no power

              Oops, wrong info.
              Last edited by budm; 12-11-2014, 09:45 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

              • triplefour
                Badcaps Legend
                • May 2014
                • 1747
                • USA

                #67
                Re: Sanyo DP42740 no power

                update: i had to upload this on youtube cause i cant quite describe what im seeing here now

                https://www.youtube.com/watch?v=hwo4...ature=youtu.be

                description:"first the tv worked normal for a whole day before shutting down. then it worked normal for an hour or two. then an hour. then not at all. then we let it rest a few days and it worked for a couple hours again and then shut down. so i figured we had a power supply problem and ordered the replacement PSU. before installing the replacement PSU, i powered up the tv one last time just to check, and everything worked fine. probly woulda stayed on for an hour again, i dont know. so i decided to change the PSU anyway. the replacement PSU would not even power the backlights. it would just click on with the green light and then off in 1 second.
                so i put the orginal back in, and it did the exact same thing! so i let it rest for a few days again. when i came back to it, it would now power on but i was just getting a blank backlit screen. i could tell everything else was working fine because i was able to change the input to av1 and hear my gamecube, just not see it. so i followed the troubleshooting steps in the service manual, unplugging certain boards and checking certain pins for shorts. didnt find any shorts. then i got to this step:
                "not shorted = Power ON TV, and check TPVSUS (SN2, pin #1) for 191V before shutdown
                If no output, = SMPS N/G
                If 191V OK is before shutdown, SN Bd. may be defective (can not be sure)"
                with some of the connectors unplugged, the tv goes into a shutdown mode after 1 seconds but apparently you're supposed to see voltage on that pin for a second. but i dont see any.
                so that doesnt look good, i think to myself. but then i wonder how can i be seeing a backlight then if there is no voltage on that pin?
                so i plug everything back in to see what the voltage would be then, and if the tv would still come on. now i measure that same pin and get 200v and well...this is what im seeing on the screen. in some scenes it looks alright but just a bit grainy and in other scenes it seems like its displaying 2 images at once. what's going on here?"
                Don't fear the repair...

                Comment

                • triplefour
                  Badcaps Legend
                  • May 2014
                  • 1747
                  • USA

                  #68
                  Re: Sanyo DP42740 no power

                  input, anyone please?
                  Don't fear the repair...

                  Comment

                  • triplefour
                    Badcaps Legend
                    • May 2014
                    • 1747
                    • USA

                    #69
                    Re: Sanyo DP42740 no power

                    must be the holidayze :/
                    Don't fear the repair...

                    Comment

                    • triplefour
                      Badcaps Legend
                      • May 2014
                      • 1747
                      • USA

                      #70
                      Re: Sanyo DP42740 no power

                      ugh...either youtube took my video down for some reason, or it was never up there to begin with...or i copied the wrong link...
                      either way heres the video
                      https://www.youtube.com/watch?v=hwo4OtgHZIc
                      and can someone please please advise me what this is?
                      im not too familiar with plasma TV's... and i havent seen this kind of image distortion before.
                      Last edited by triplefour; 01-13-2015, 06:10 AM.
                      Don't fear the repair...

                      Comment

                      • triplefour
                        Badcaps Legend
                        • May 2014
                        • 1747
                        • USA

                        #71
                        Re: Sanyo DP42740 no power

                        does no one have any idea what im looking at here?
                        Don't fear the repair...

                        Comment

                        • Agent24
                          I see dead caps
                          • Oct 2007
                          • 4913
                          • New Zealand

                          #72
                          Re: Sanyo DP42740 no power

                          Maybe the voltage is supposed to be 191v and at 200v is too high?
                          "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                          -David VanHorn

                          Comment

                          • triplefour
                            Badcaps Legend
                            • May 2014
                            • 1747
                            • USA

                            #73
                            Re: Sanyo DP42740 no power

                            yeah maybe but i have no idea what im looking at here. i barely know what im looking at with regular LCD's but im totally lost on the plasmas...plus its heavy and hard to work with. its just been sitting collecting dust for months now
                            Don't fear the repair...

                            Comment

                            • Agent24
                              I see dead caps
                              • Oct 2007
                              • 4913
                              • New Zealand

                              #74
                              Re: Sanyo DP42740 no power

                              I don't know much about plasmas either. Never worked on one, only CRT and LCD so far. Hopefully some of the other guys can help you. Only thing I can suggest is reading threads on here, and looking at repair guides\videos and plasma set operation theory. It probably won't help you fix it, but it should help you learn something so that at least you know where you are and know the basics.
                              "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                              -David VanHorn

                              Comment

                              • triplefour
                                Badcaps Legend
                                • May 2014
                                • 1747
                                • USA

                                #75
                                Re: Sanyo DP42740 no power

                                thats great advice. sadly when i first joined here i had a lot of time, and did quite a bit of learning. but now since i know enough to be dangerous, it seems like i dont have the time to learn more! too busy fixing the TV's that dont put up as much of a fight! ...which i cant really complain about since i AM fixing them and making money now. except that im not really progressing anymore in my education.i will get back on it soon enough though...gotta pay them bills first! ...and buy a hot air/reflow station...and fix up that oscilloscope i scored... and... and...
                                Last edited by triplefour; 02-01-2015, 10:53 PM.
                                Don't fear the repair...

                                Comment

                                • dstafursky
                                  New Member
                                  • Dec 2016
                                  • 1
                                  • USA

                                  #76
                                  Re: Sanyo DP42740 no power

                                  Originally posted by triplefour
                                  resistance between 1 and 2 is 0.5ohms
                                  when i put my meter in diode mode, i get 620 when i have the black probe on the side with the line, and 1 with the probes reversed.
                                  when in resistance mode i get 35kohms with black on line and 55kohms with probes reversed.
                                  the numbers on the IC are
                                  TB5AH
                                  6754MR

                                  the DC voltage across the legs on cap rj15 is fluctuating ...as low as 6v and as high as 20v

                                  thank you!
                                  My voltage is zero...any ideas?

                                  Comment

                                  Related Topics

                                  Collapse

                                  • Tynan Dill
                                    Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?
                                    by Tynan Dill
                                    I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.

                                    Upon bringing it home and plugging it up, it showed a standby light.

                                    I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.

                                    The screen seems to blackout and stay black, but with a flashlight I can see the display.

                                    With my Playstation 4 connected via HDMI, and running a game I can hear sound.

                                    Assuming...
                                    11-22-2024, 01:46 PM
                                  • PantherDave
                                    Microsoft Surface Pro (5th gen) model 1796 - no power
                                    by PantherDave
                                    Hi all!

                                    I'm trying to troubleshoot a Microsoft Surface Pro (5th gen) model 1796 that won't power on. Motherboard model is M1007506-015. My priority is retrieving data, but the SSD is integrated so it looks like if I can't repair it it'll need to go to a data recovery company. I've done a little basic board repair before, but nothing this advanced until now. So please forgive my ignorance in advance. 😅

                                    I found the boardview for this laptop in the forums here, and am able to open it on my PC with FlexBV.
                                    https://www.badcaps.net/forum/troubl...-hardware-devi...
                                    05-29-2024, 02:01 PM
                                  • GLISIT
                                    Asus Probook P5440UF-XB74 power issue
                                    by GLISIT
                                    Hi all,

                                    TL;DR - this laptop is driving me nuts with the oddball power-related behaviors. Appreciate any insight you can provide!


                                    I'm experiencing a power issue on an Asus Probook P5440UF-XB74. Although I've worked with electronics and computers for decades, this is my first attempt at getting into motherboard-level component troubleshooting. Any help the community can provide is greatly appreciated!

                                    A few weeks ago I was using the laptop (on battery power) for a Zoom meeting. The battery was running very low (long meeting) but I wasn't worried about...
                                    01-16-2025, 02:29 PM
                                  • sam_sam_sam
                                    Desoldering gun station modified to use a 18 volt @ 20 amp switching power supply
                                    by sam_sam_sam
                                    I have wanting to do this project for quite sometime now and I finally found a switching power supply that will work on this desoldering gun station ZD-915 that the original switching power supply took a shit and just was not worth trying to fix it because this switching power is not quite big enough to handle the heater element and the vacuum pump

                                    One note when I tested the switching power supply and the voltage control board I noticed that this desoldering gun heat up much faster than the original switching power supply which I was really surprised by to the point that I might buy...
                                    03-31-2024, 02:12 PM
                                  • Document Archive
                                    HP Pavilion Power Pavilion Power 15-cb009nl Notebook 15 Specification for Upgrade or Repair
                                    by Document Archive
                                    This specification for the HP Pavilion Power Pavilion Power 15-cb009nl Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the Pavilion Power 15-cb009nl boardview and Pavilion Power 15-cb009nl schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that...
                                    09-06-2024, 05:59 AM
                                  • Loading...
                                  • No more items.
                                  Working...