Recapped Magnavox 42mf531d/37 still no inverter lights

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • snake91876
    Badcaps Veteran
    • Feb 2013
    • 236
    • United States

    #1

    Recapped Magnavox 42mf531d/37 still no inverter lights

    I have a magnavox 42mf531d/37 lcd . 4 caps were popped on power supply. It would not do nothing. Replaced the three 1500uf 35v caps and the 2200uf 25v and now it sounds like its coming on but still doesnt light back light. I have 24v at the plugs going to each side of the inverter boards but its like somethings not telling them to come on. I can slightly unplug the left board and the backlights begin to flash but wont stay on its like its jumping the voltage to another pin. What direction now.
  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK

    #2
    Re: Recapped Magnavox 42mf531d/37 still no inverter lights

    Check BLON, DIM on connector. You have 24V and GND wires, then two wires for the BLON and DIM.
    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

    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA

      #3
      Re: Recapped Magnavox 42mf531d/37 still no inverter lights

      Also check the caps in both inverter boards, all fuses, especially if it has small black fuse with '15' or '20' on the top. Also inspect the IC and the MOSFETs of both boards.
      Chassis number of this TV?
      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

      • snake91876
        Badcaps Veteran
        • Feb 2013
        • 236
        • United States

        #4
        Re: Recapped Magnavox 42mf531d/37 still no inverter lights

        Alright on powersupply voltage on plugs to backlights

        Left backlight right backlight

        0v von 0v g
        0v vdim 0v g
        0v g 0v g
        0v g 0v g
        0v g 0v g
        0v g 24v v
        0v g 24v v
        24v v 24v v
        24v v 24v v
        24v v 24v v
        24v v
        24v v

        Comment

        • budm
          Badcaps Legend
          • Feb 2010
          • 40746
          • USA

          #5
          Re: Recapped Magnavox 42mf531d/37 still no inverter lights

          OK, it is not getting either BL_ON (Von), or the Dimming signal (Vdim) from the main board.
          Time for more pictures of the boards.
          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

          • snake91876
            Badcaps Veteran
            • Feb 2013
            • 236
            • United States

            #6
            Re: Recapped Magnavox 42mf531d/37 still no inverter lights

            Here are the pics i did find a smoked place on the cover over the main board it was directly over the black square thing in the bottom middle of picture 5.
            Attached Files

            Comment

            • budm
              Badcaps Legend
              • Feb 2010
              • 40746
              • USA

              #7
              Re: Recapped Magnavox 42mf531d/37 still no inverter lights

              So far I cannot find the service manual for this model, we will need that to troubleshoot the main board. Is there chassis number on the model number sticker tag? Something like Model number xxxxx TPE1.0U-LA
              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

              • snake91876
                Badcaps Veteran
                • Feb 2013
                • 236
                • United States

                #8
                Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                No additional
                information was on tag
                just the 42mf number.

                Comment

                • tom66
                  EVs Rule
                  • Apr 2011
                  • 32560
                  • UK

                  #9
                  Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                  Can we see the tag? Very strange if that is the case.
                  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

                  • tom66
                    EVs Rule
                    • Apr 2011
                    • 32560
                    • UK

                    #10
                    Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                    One other thing, those axial lead Nichicon are not low esr so not suitable for the PSU. Not going to be a problem yet (24V is good) but may be a problem when under load or after the caps have aged.
                    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

                    • snake91876
                      Badcaps Veteran
                      • Feb 2013
                      • 236
                      • United States

                      #11
                      Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                      Where is the tag located you want to see.

                      Comment

                      • tom66
                        EVs Rule
                        • Apr 2011
                        • 32560
                        • UK

                        #12
                        Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                        The tag which you state only has the model. It may be in a different encoding.
                        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

                        • RON_CET
                          Badcaps Veteran
                          • Jun 2012
                          • 217
                          • USA

                          #13
                          Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                          I have the service data if needed it 's large file I'll be glad to upload or send
                          also have the panel info just need the information on sticker in set there's about 4 panel version
                          Last edited by RON_CET; 05-11-2013, 09:39 AM.
                          Ron Driver,BSEE,CET,ISCET,NESDA

                          Comment

                          • snake91876
                            Badcaps Veteran
                            • Feb 2013
                            • 236
                            • United States

                            #14
                            Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                            Here are pics of back of tv cover, and back of lcd panel with the requested information on them.
                            Attached Files

                            Comment

                            • RON_CET
                              Badcaps Veteran
                              • Jun 2012
                              • 217
                              • USA

                              #15
                              Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                              Here's the service data from your picture for the panel,also attached is a service bulletin,check make sure your serial number falls within the scope of this bulletin,hope this information helps
                              Attached Files
                              Ron Driver,BSEE,CET,ISCET,NESDA

                              Comment

                              • snake91876
                                Badcaps Veteran
                                • Feb 2013
                                • 236
                                • United States

                                #16
                                Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                                Not that familiar with surface soldering, repalcing these things fix the signal power to the inverter boards.

                                Comment

                                • snake91876
                                  Badcaps Veteran
                                  • Feb 2013
                                  • 236
                                  • United States

                                  #17
                                  Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                                  I have just noticed this repair is for a 42mf231d/37 and i have a 531d so this
                                  would not apply to my unit.

                                  Comment

                                  • snake91876
                                    Badcaps Veteran
                                    • Feb 2013
                                    • 236
                                    • United States

                                    #18
                                    Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                                    I have checked diodes on power supply none were shorted except one that was setting the meter off both ways , i took it out of the board and it tested normal i guess its in a parallell or something. Anyway diodes seem to be ok.

                                    Comment

                                    • tom66
                                      EVs Rule
                                      • Apr 2011
                                      • 32560
                                      • UK

                                      #19
                                      Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                                      Well, you have 24V, problem is not on PSU...
                                      VON is your problem, so mainboard has to be considered.
                                      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

                                      • snake91876
                                        Badcaps Veteran
                                        • Feb 2013
                                        • 236
                                        • United States

                                        #20
                                        Re: Recapped Magnavox 42mf531d/37 still no inverter lights

                                        Well i know that the main board had a couple of smoked spots so i may have to try another board. thanks

                                        Comment

                                        Related Topics

                                        Collapse

                                        • x_orange90_x
                                          Vizio E55-E1 bad backlights or bad inverter?
                                          by x_orange90_x
                                          I just got this tv today and it appeared to have no backlight on. After taking off the rear cover and checking again in the dark I can see that MAYBE one quadrant is lit.. But still it's quite dim. I was going to check the LEDs with my tester, and I found LED 1 and LED 2 + pins on the wire from the inverter, but I couldn't identify a ground. Nonetheless I tried using a mounting screw on the inverter board and also the chassis as ground but regardless my tester reads 300 which is what it reads when there is no voltage draw.

                                          I don't know how exactly to test the inverter itself. Is it...
                                          01-29-2025, 09:24 PM
                                        • lostone
                                          Looking for help with a Viewsonic VP230mb where the backlight comes on only momentarily
                                          by lostone
                                          Hello, I came here after finding some similar questions asked on other monitors and hope someone here can help me get an ancient Viewsonic VP230mp (23" 4:3 LCD) back to working condition.

                                          First a little background, I have a background in computer and electrical engineering, and I'm smart enough to know I know nothing about LCD displays and how they work. For this topic I'm as green as they come.
                                          When the display is turned on the viewsonic logo displays in the uppper left for 2 seconds then the screen goes black, the power LED is green (on) and when a computer is connected...
                                          05-19-2024, 11:40 AM
                                        • Gentian
                                          APSINT3636VR 3600W APS INT Series 36V DC 230V AC Inverter/Charger schematic
                                          by Gentian
                                          I have a tripp-lite aspint 3636vr inverter charger which blow some of mosfet transistors. I replaced them repaired also the driver circuit and tested but the mosfets burn again.

                                          It work very well as inverter and also as charger if I let the rear switch in auto mode (inverter) and charger only(charging) but in auto when I connect the feed line 220V AC first time it pass ok to line and start charging the batteries but when I remove the feed line it pass to inverter mode and if I do it again the second time when passing from charging to inverter the Main transformer start making a...
                                          03-06-2023, 07:07 AM
                                        • valvashon
                                          Insignia NS-LCD19-09 (PS OK, Inverter problem?)
                                          by valvashon
                                          For some reason I'm just not going to let this 19" TV defeat me. I guess because I have a schematic to work from I feel like I'm oh so close.

                                          History- while adding a turn-on circuit I let a small screw roll under the power board. Worked through all of that circuitry, probably replacing a MOSFET and PWM controller that were not bad but I was following the service manual. Finally figured out that the power supply is in working order when the inverter section (for the backlights) is disconnected. When the +12 supply to the inverter is disconnected the +12 and +5 will come up...
                                          01-04-2024, 01:44 PM
                                        • tonybig10
                                          Magnavox MDR515H/F7 And Magnavox MDR537H/F7
                                          by tonybig10
                                          Hi is any one can help me on getting the Schematics for Magnavox MDR515H/F7 And Magnavox MDR537H/F7 PDF file thank you I really appreciate it. Just need to change some component on
                                          the main board and the power supply board. I looked all over for the internet and I cannot find the Schematics sheet for both of them. I don't know where else to look I hope someone can help me...
                                          03-07-2025, 01:03 PM
                                        • Loading...
                                        • No more items.
                                        Working...