Transformer substitution - Sanyo DP42849-01

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • lookimback
    Badcaps Legend
    • Aug 2013
    • 1489
    • USA

    #41
    Re: Transformer substitution - Sanyo DP42849-01

    Oh, the inductance was 36.4mh in the rebuilt, and 39.3mh in a working stock transformer. Both tested in board. The rebuilt sounds better than any I've encountered so far too. It is completely silent. A lot of the working ones I've encountered have a light buzz/squeal to them.
    ------------signature starts here------------


    Comment

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #42
      Re: Transformer substitution - Sanyo DP42849-01

      You sure do have lots of patience on this project, great job.
      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

      • lookimback
        Badcaps Legend
        • Aug 2013
        • 1489
        • USA

        #43
        Re: Transformer substitution - Sanyo DP42849-01

        Thank you. I enjoy this stuff.
        ------------signature starts here------------


        Comment

        • lookimback
          Badcaps Legend
          • Aug 2013
          • 1489
          • USA

          #44
          Re: Transformer substitution - Sanyo DP42849-01

          After 24 hours of testing this, I think I may possibly have a problem. It seems like it's getting too hot. It doesn't smell hot, just feels hot. It's sitting right on the backlight with a plastic sheet as an insulator so that may be a contributing factor. I no longer have the housing for this, I wish I'd kept it now. I don't have a temp gauge and my stock board sold yesterday so I have no way to make any real comparison. What I do know is that I have 32.5 ohms resistance rather than 25.5 - 26.5 which was average on most working transformers I've encountered. Increased resistance is going to increase heat correct? Thinking about it, it's nearly 25% higher resistance than what I suspect it should be. So maybe I should use larger gauge conductor. I'm noticing too that in magnet wire, specifications seem to vary dependant upon manufacturer. I'm noticing now that if I give my caliper the slightest pinch, it reads 0.0045 instead of the 0.005 which I get from the old wire. I epoxied these things real good. I doubt I can disassemble them again. Advice?
          ------------signature starts here------------


          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #45
            Re: Transformer substitution - Sanyo DP42849-01

            You may have to check the circuit current draws and compare it to the working original to see if the circuit is drawing too much current.
            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

            • lookimback
              Badcaps Legend
              • Aug 2013
              • 1489
              • USA

              #46
              Re: Transformer substitution - Sanyo DP42849-01

              Would I measure the current with a clamp ammeter on the wires connecting it to the backlight? Also, I do have a few other board waiting for transformers. Maybe, since I don't have a working original at this time, I should put the transformer on a different board and see if it is the same.
              ------------signature starts here------------


              Comment

              • budm
                Badcaps Legend
                • Feb 2010
                • 40746
                • USA

                #47
                Re: Transformer substitution - Sanyo DP42849-01

                You will use your digital meter in DC A mode and connect it in series with power supply line that feeds the inverter circuit to see the circuit current draw, or if it has the fuse for each section of the transformer drive circuit then you can put your meter in place of the fuse to see current draw of that section and compare it to the section that has original transformer.
                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

                • lookimback
                  Badcaps Legend
                  • Aug 2013
                  • 1489
                  • USA

                  #48
                  Re: Transformer substitution - Sanyo DP42849-01

                  Only has the 1 fuse on it. So I would pull the fuse then and connect the meter in series. OK. Thanks.
                  ------------signature starts here------------


                  Comment

                  • budm
                    Badcaps Legend
                    • Feb 2010
                    • 40746
                    • USA

                    #49
                    Re: Transformer substitution - Sanyo DP42849-01

                    Yes, I am surprised that it only has one fuse.
                    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

                    • lookimback
                      Badcaps Legend
                      • Aug 2013
                      • 1489
                      • USA

                      #50
                      Re: Transformer substitution - Sanyo DP42849-01

                      This is the only fuse I see.
                      Attached Files
                      ------------signature starts here------------


                      Comment

                      • lookimback
                        Badcaps Legend
                        • Aug 2013
                        • 1489
                        • USA

                        #51
                        Re: Transformer substitution - Sanyo DP42849-01

                        I get 1.68 amps. And as stated, I don't currently have a board with an original transformer. I have 2 more coming though so I might have a good one within a week. I'll cross my fingers and hope one is good. I've worked on at least 10 of these so far though and only 3 had good transformers, so the odds are not in my favor.
                        ------------signature starts here------------


                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA

                          #52
                          Re: Transformer substitution - Sanyo DP42849-01

                          There may be a fusible resistor for feeding the Voltage to that inverter circuit where the power MOSFETs are mounted on that heat sink to the right of the inverter transformer. You can then check the voltage drops on that fusible resistor to calculate the current draw.
                          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

                          • lookimback
                            Badcaps Legend
                            • Aug 2013
                            • 1489
                            • USA

                            #53
                            Re: Transformer substitution - Sanyo DP42849-01

                            Can you tell from these pics which one it would be?
                            Attached Files
                            ------------signature starts here------------


                            Comment

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA

                              #54
                              Re: Transformer substitution - Sanyo DP42849-01

                              It looks like you will be measuring the DC Voltage across fusible resistor R322 which is fed by the B+ from the positive pin of the main filter cap C821, this resistor will show the total current draw of the Inverter, standby power supply and the third supply I cannot clearly see from the picture, but this will give you some idea of the current draw, the inverter circuit will draw most of the current.
                              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

                              • lookimback
                                Badcaps Legend
                                • Aug 2013
                                • 1489
                                • USA

                                #55
                                Re: Transformer substitution - Sanyo DP42849-01

                                OK, I will take the readings tomorrow and post back with the results and calculations.
                                ------------signature starts here------------


                                Comment

                                • lookimback
                                  Badcaps Legend
                                  • Aug 2013
                                  • 1489
                                  • USA

                                  #56
                                  Re: Transformer substitution - Sanyo DP42849-01

                                  I finally came up with another working board with a stock transformer. That board draws 1.45 amps and both with rebuilt transformers draw 1.68 amps. It's also the same if I put them on different boards, as I have a few spares without transformers. I ordered a laser temperature probe. When it arrives, I'll see what the actual temp differential is. I have a feeling I am going to have to up the gauge on the magnet wire. Also, I got the exact same voltage on both sides of resistor R322. Maybe I didn't do it right. I measured from the negative pin of the main filter cap C821.

                                  Got the digital proximity sensor counter installed and working in my winding jig too. Pic attached.
                                  Attached Files
                                  ------------signature starts here------------


                                  Comment

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #57
                                    Re: Transformer substitution - Sanyo DP42849-01

                                    You have to measure across the resistor, not ref to the circuit ground (the negative leg of the cap). You will put one probe on each end of the R322 which is very low Ohm resistor to measure the Voltage drop on the resistor, then you can calculate the current draw, but since you already made the current measurement then you already know the re-built Xformer is drawing more current (16% higher) than the original, just have to figure out why.
                                    Last edited by budm; 08-15-2014, 09:42 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

                                    • lookimback
                                      Badcaps Legend
                                      • Aug 2013
                                      • 1489
                                      • USA

                                      #58
                                      Re: Transformer substitution - Sanyo DP42849-01

                                      Could the wire gauge be the cause? Resistance is 12 ohms higher (6 per side) than the average working transformers.

                                      Here's the readings.

                                      Board with original transformer: 0.038vdc

                                      Board with rebuilt transformer: 0.041vdc
                                      ------------signature starts here------------


                                      Comment

                                      • budm
                                        Badcaps Legend
                                        • Feb 2010
                                        • 40746
                                        • USA

                                        #59
                                        Re: Transformer substitution - Sanyo DP42849-01

                                        It could be the inductance, the DCR, and the turn count, or the core is being saturated so the inductance will drop and cause more current draw. When they design the circuits, they take lots of values into account.
                                        http://www.edaboard.com/thread199057.html
                                        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

                                        • lookimback
                                          Badcaps Legend
                                          • Aug 2013
                                          • 1489
                                          • USA

                                          #60
                                          Re: Transformer substitution - Sanyo DP42849-01

                                          Turn count is definitely correct. I was meticulous with that. I get what you are saying about inductance. So if the core is saturating, that would mean the inductor never reaches it's resonant frequency. Correct? Would the impedance of the inductor affect it's resonant frequency and result in saturation? There's certainly more to this than rewinding the transformer. I'll put some more time into this tomorrow. Thanks again too.
                                          ------------signature starts here------------


                                          Comment

                                          Related Topics

                                          Collapse

                                          • mikey5791
                                            Is it possible for transformer substitution?
                                            by mikey5791
                                            Hi all,
                                            Got this local made DC power supply (12/14V) given free as the transformer has melted. There is no marking or indication to identify what type or rating of transformer used.
                                            Fyi,. I had a busted autogate mainboard with transformer with marking 13-0-13 . Is this the 13v dc type transformer?
                                            My questions are
                                            1. How do i test to see if the transformer is in good working condition?
                                            2. Can this transformer (marking 13-0-13) be used to replace the melted transformer on the DC power supply?
                                            Hope you guys understand what i was asking. My intention is...
                                            11-03-2022, 02:11 AM
                                          • ohren
                                            Original Xbox 1.0 PSU: Foxlink FTPS-0002 Rev. B. — 12 V low, 5 V high — transformer?
                                            by ohren
                                            Hello!

                                            I'm looking at an original Xbox PSU: Foxlink ftps-0002 rev. B. The 12 V output is too low, and the 5 V output is too (?) high. Unfortunately I don't have an oscilloscope but only a DMM for diagnosis.

                                            Measured voltages with no load:

                                            After rectifier diodes
                                            12V: 6.17 V
                                            5V: 5.67 V

                                            Secondary transformer pins AC measurement (really don't know if this says anything)
                                            12V: 2-2.5 V
                                            5V: 1.04 V


                                            I also have another (working) Xbox psu from Delta. The same measures there, in order, being: 10.79,...
                                            03-18-2023, 10:33 AM
                                          • dennis_elx33
                                            3PHASE STEP-DOWN Transformer in Check
                                            by dennis_elx33
                                            Hello All,

                                            i would like to post an interesting topic regarding 3-phase stepdown transformer which we suspect to cause an overcurrent (138A) which resulted to power tripped off of the HV power supply (80KV output).


                                            Problem statement: Power tripped Off

                                            Initial Problem: Found 2 IGBT and 2 rectifier diodes shorted (burnt).

                                            Action Done:
                                            1) Replaced the faulty parts with good spare.
                                            2) Measured impedance of the 3phase input lines and found that L2 to L3 has 23.3ohm while other pairs are 51Kohm. This pins will...
                                            12-02-2024, 06:52 AM
                                          • Document Archive
                                            ASUS Transformer T101HA - X5DHD Hybrid (2-in-1) Book Specification for Upgrade or Repair
                                            by Document Archive
                                            This specification for the ASUS Transformer T101HA - X5DHD Hybrid (2-in-1) 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 T101HA - X5DHD boardview and T101HA - X5DHD 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 any specification, datasheet,...
                                            09-06-2024, 04:40 PM
                                          • Document Archive
                                            ASUS Transformer T304UA-P71SP-CA Hybrid (2-in-1) Pro Specification for Upgrade or Repair
                                            by Document Archive
                                            This specification for the ASUS Transformer T304UA-P71SP-CA Hybrid (2-in-1) 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 T304UA-P71SP-CA boardview and T304UA-P71SP-CA 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 any specification, datasheet,...
                                            09-06-2024, 12:00 PM
                                          • Loading...
                                          • No more items.
                                          Working...