Sanyo DP42740 no power

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • triplefour
    Badcaps Legend
    • May 2014
    • 1747
    • USA

    #1

    Sanyo DP42740 no power

    got my first plasma TV to attempt a repair on today.
    a friend of mine said if i can fix it we'll sell it and split the money.
    the people he got it from gave this story as to why its broken:
    "we were watching it, during a lightning storm, when it suddenly turned off and wouldn't turn back on again. nothing else in the house was affected. we were not hit by the lightning or anything"

    at any rate, i plugged it in and i do not get a standby light or anything and pushing the power does nothing.
    it has a million screws in the back for some reason. but i took them all out and got some pictures of the boards.

    i know that plasmas are much different from the LCD's so i dont really know what im looking at here.

    where should i start? on the LCD boards there is usually one big capacitor on the power board. the main filter cap. but on this board there are 4 big capacitors.

    is working on a plasma TV any more dangerous than LCD or LED tvs?
    Attached Files
    Don't fear the repair...
  • martino
    Not so "senior"
    • Aug 2013
    • 997
    • canada

    #2
    Re: Sanyo DP42740 no power

    No standby light would put the powersupply at first suspect I'd say.
    Is there a legend printed at the connector that goes to the mainboard?
    Assuming you already checked the fuses F201,F202,F204?
    First we need to figure out if you get the standby voltage.I'm trying to find a schematic..
    Working on plasma's is not more dangerous then a lcd tv,yes,there is the VA and VS voltage of 200+dc volt etc,but 1000volt plus on a lcd tv for inverter doesnt feel nice either
    Bigger caps on power supply you have to watch for,they hold a good charge for awhile after unplugging,best to drain them with a heavy resistor before poking around on that board(been there,done that,trust me,doesnt feel nice at all)
    Last edited by martino; 07-31-2014, 10:59 PM.
    Proud owner of dozens of broken TV's and many,many,many boards.


    Our website and passion:http://hollenhundshepherds.com/

    Comment

    • martino
      Not so "senior"
      • Aug 2013
      • 997
      • canada

      #3
      Re: Sanyo DP42740 no power

      "borrowed" a picture from the psu

      http://www.toms-service-manuals.com/...h=Submit+Query

      There ya go for schematics,thank tom66 for his amazing database.super handy
      Attached Files
      Proud owner of dozens of broken TV's and many,many,many boards.


      Our website and passion:http://hollenhundshepherds.com/

      Comment

      • triplefour
        Badcaps Legend
        • May 2014
        • 1747
        • USA

        #4
        Re: Sanyo DP42740 no power

        yeah thats what mine looks like...
        Attached Files
        Don't fear the repair...

        Comment

        • triplefour
          Badcaps Legend
          • May 2014
          • 1747
          • USA

          #5
          Re: Sanyo DP42740 no power

          awesome. i guess i better go thru everything in this service manual and then report back. thanks!
          Don't fear the repair...

          Comment

          • johnboy1313
            Badcaps Legend
            • Nov 2012
            • 1959
            • USA

            #6
            Re: Sanyo DP42740 no power

            Set your meter to the highest DC volts setting and check across the leads on one of the big 450V caps at the top of the PSU, with the set plugged in. Red on one leg, black on the other. Report back.

            Comment

            • selldoor
              Slow Learner
              • Dec 2010
              • 7870

              #7
              Re: Sanyo DP42740 no power

              A good in focus straight on picture of the front and back of the power supply might help.
              Not able to see much at all on the one you posted.
              Please upload pictures using attachment function when ask for help on the repair
              http://www.badcaps.net/forum/showthread.php?t=39740

              Comment

              • martino
                Not so "senior"
                • Aug 2013
                • 997
                • canada

                #8
                Re: Sanyo DP42740 no power

                The big main caps are probably not active till the psu gets forced on. Might not see a voltage on those in standby.
                Proud owner of dozens of broken TV's and many,many,many boards.


                Our website and passion:http://hollenhundshepherds.com/

                Comment

                • johnboy1313
                  Badcaps Legend
                  • Nov 2012
                  • 1959
                  • USA

                  #9
                  Re: Sanyo DP42740 no power

                  If the set is in standby, he should still see roughly 170V, if not roughly 400V. I had the same set with the same symptoms. My PSU was stuck ON.

                  https://www.badcaps.net/forum/showthread.php?t=28850
                  Last edited by johnboy1313; 08-01-2014, 01:58 PM.

                  Comment

                  • triplefour
                    Badcaps Legend
                    • May 2014
                    • 1747
                    • USA

                    #10
                    Re: Sanyo DP42740 no power

                    i get no volts at the big caps (well the 2 i can test without turning over the board anyway)
                    and i only get 84v AC from the plug... shouldnt it be 120?
                    Don't fear the repair...

                    Comment

                    • triplefour
                      Badcaps Legend
                      • May 2014
                      • 1747
                      • USA

                      #11
                      Re: Sanyo DP42740 no power

                      at the very beginning of the service manual it says
                      "An isolation transformer must be connected in the power
                      line between the receiver and the AC line before any service
                      is performed on the receiver"

                      is this really true? what is an isolation transformer anyway?
                      Don't fear the repair...

                      Comment

                      • budm
                        Badcaps Legend
                        • Feb 2010
                        • 40746
                        • USA

                        #12
                        Re: Sanyo DP42740 no power

                        It is for safety when you are probing around the Primary (Deadly) side of the circuit, you should have 120VAC right at the AC connector on the board. Is your meter's battery OK?
                        Example of Isolation transformer:
                        https://cdn.badcaps-static.com/pdfs/...4cc7e77847.pdf
                        Last edited by budm; 08-01-2014, 05:14 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

                          #13
                          Re: Sanyo DP42740 no power

                          i dont think my meters battery is bad. i can test double A batteries and i get the same readings as with my analog meter...
                          Don't fear the repair...

                          Comment

                          • triplefour
                            Badcaps Legend
                            • May 2014
                            • 1747
                            • USA

                            #14
                            Re: Sanyo DP42740 no power

                            selldoor, in post 3 there is a clear picture of the power board (from the front anyway)
                            ill try to take a good one of the back.
                            Don't fear the repair...

                            Comment

                            • triplefour
                              Badcaps Legend
                              • May 2014
                              • 1747
                              • USA

                              #15
                              Re: Sanyo DP42740 no power

                              ok heres the pictures of the back. the board is pretty big so i couldnt take a detailed picture of the whole thing so i did it in sections as well.
                              Attached Files
                              Don't fear the repair...

                              Comment

                              • triplefour
                                Badcaps Legend
                                • May 2014
                                • 1747
                                • USA

                                #16
                                Re: Sanyo DP42740 no power

                                ok i re-tested the AC volts and i do get 120 now. i dunno what that 84v was about but its 120 now... how do i test for 5v standby? i get no volts across the capacitors. no volts across any of the fuses either. what should i use for ground ref to test the volts at the connectors? and how do i tell which one is standby? theres no legend anywhere!
                                Last edited by triplefour; 08-01-2014, 07:13 PM.
                                Don't fear the repair...

                                Comment

                                • budm
                                  Badcaps Legend
                                  • Feb 2010
                                  • 40746
                                  • USA

                                  #17
                                  Re: Sanyo DP42740 no power

                                  So you do not have aboyt 165~170VDC measured right at the two legs of the main filter caps (100uF 450VDC)?
                                  All three fuses show <1 Ohms? measure them with TV unplugged.
                                  Last edited by budm; 08-01-2014, 08:57 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

                                    #18
                                    Re: Sanyo DP42740 no power

                                    yes the fuses are not open. and with the tv plugged in i get 0v on the filter caps (the 2 i can measure without flipping the board over that is)
                                    Don't fear the repair...

                                    Comment

                                    • budm
                                      Badcaps Legend
                                      • Feb 2010
                                      • 40746
                                      • USA

                                      #19
                                      Re: Sanyo DP42740 no power

                                      OK, I will have to trace out the connections from each leg of the AC inlet all the way to the two inner legs of the bridge rectifier. That will take awhile. I did not download all the pictures of the bottom side of the board yet, hopefully they are clear enough for me to trace out the connections.
                                      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

                                      • budm
                                        Badcaps Legend
                                        • Feb 2010
                                        • 40746
                                        • USA

                                        #20
                                        Re: Sanyo DP42740 no power

                                        OK, luckily shopjimmy has good pictures of the top and the bottom side of the board.
                                        http://www.shopjimmy.com/sanyo-n0ae5...ply-board.htm#
                                        You can test the board by itself to see if you are getting the DC Voltage on the filter cap CE203 which is the filter cap for the standby power supply, measure right at the two legs of the cap.
                                        Last edited by budm; 08-01-2014, 11:41 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

                                        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...