Is it possible to bench test an inverter board?

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  • tucocaps
    Badcaps Veteran
    • Apr 2013
    • 331
    • United Stated

    #1

    Is it possible to bench test an inverter board?

    On a recent ebay sale, I think I've got a bad buyer who might be returning me his broken inverter for a "refund". Claims the power supply was the problem, but I've heard that bad power supplies can burn out inverters anyway.

    Also, are there unique serial numbers or markings on some tv boards?

    Thanks much for any ideas.
  • SteveNielsen
    Retired Tech
    • Jun 2012
    • 2327
    • USA

    #2
    Re: Is it possible to bench test an inverter board?

    Yes it is possible to test an inverter board on the bench, which raises the question; Was it tested and working before you sold it?

    Comment

    • tucocaps
      Badcaps Veteran
      • Apr 2013
      • 331
      • United Stated

      #3
      Re: Is it possible to bench test an inverter board?

      steve: The panel had backlight and color, but was cracked.

      Comment

      • tucocaps
        Badcaps Veteran
        • Apr 2013
        • 331
        • United Stated

        #4
        Re: Is it possible to bench test an inverter board?

        So , how do I go about the bench testing? Thanks for any help.

        Comment

        • SteveNielsen
          Retired Tech
          • Jun 2012
          • 2327
          • USA

          #5
          Re: Is it possible to bench test an inverter board?

          Please post the make/model info and good pics of the top and bottom of the inverter board. Then someone here can probably help you.

          Comment

          • tom66
            EVs Rule
            • Apr 2011
            • 32560
            • UK

            #6
            Re: Is it possible to bench test an inverter board?

            It is extremely rare for a PSU to kill an inverter in any way. The inverter will be fine. What you should do is check transistors & fuse on it, and in future write down a unique serial number on it.
            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

            • DemonBG
              Senior Member
              • Mar 2012
              • 143
              • USA

              #7
              Re: Is it possible to bench test an inverter board?

              your best bet for the future to prevent something like this happening is to put a small (with a permanent marker or such like) mark somewhere inconspicuous such that only you know its there - if they send their own, faulty one back then you know they have tried a switcharoo!

              good luck,
              Demon

              Comment

              • selldoor
                Slow Learner
                • Dec 2010
                • 7870

                #8
                Re: Is it possible to bench test an inverter board?

                Originally posted by tucocaps
                On a recent ebay sale, I think I've got a bad buyer who might be returning me his broken inverter for a "refund". Claims the power supply was the problem, but I've heard that bad power supplies can burn out inverters anyway.

                Also, are there unique serial numbers or markings on some tv boards?

                Thanks much for any ideas.
                I think you need to clarify what you mean.
                What did you Sell. Power supply Main Board Inverter
                On two or all three
                Is he saying he bought an inverter and his power supply broke it?
                Is he saying he bought a power supply and it broke his inverter?
                Is he saying he bought both and both are faulty?


                Dont you have pictures of the items you sell on ebay? almost every board
                will have a slight difference.
                Please upload pictures using attachment function when ask for help on the repair
                http://www.badcaps.net/forum/showthread.php?t=39740

                Comment

                • tucocaps
                  Badcaps Veteran
                  • Apr 2013
                  • 331
                  • United Stated

                  #9
                  Re: Is it possible to bench test an inverter board?

                  40MF401B/F7 backlight inverter. Here is a picture. I think the board may be the same one sent to the buyer, but would like to make sure it's still in working order. Thanks for any idea on how to bench test this.

                  Attached Files

                  Comment

                  • tucocaps
                    Badcaps Veteran
                    • Apr 2013
                    • 331
                    • United Stated

                    #10
                    Re: Is it possible to bench test an inverter board?

                    anyone have an idea on how to test this? thanks!

                    Comment

                    • SteveNielsen
                      Retired Tech
                      • Jun 2012
                      • 2327
                      • USA

                      #11
                      Re: Is it possible to bench test an inverter board?

                      Without a schematic for the board you still might be able to figure it out from the pinout and specs of the chip that is below the white connectors in your picture.

                      Comment

                      • johnboy1313
                        Badcaps Legend
                        • Nov 2012
                        • 1959
                        • USA

                        #12
                        Re: Is it possible to bench test an inverter board?

                        I sent a working main board from a set with a bad tab bond out a few weeks ago with a serialized "VOID IF REMOVED" label clearly stuck on the back. The buyer claimed it didn't work and sent a board back with no sticker on it, that was warped, had obvious other damage, and had a different serial number on the OEM label. I had pictures showing what I sent and what I received. Ebay still refunded his money. He claimed that he sent my board and that I must have swapped it.

                        Comment

                        • SteveNielsen
                          Retired Tech
                          • Jun 2012
                          • 2327
                          • USA

                          #13
                          Re: Is it possible to bench test an inverter board?

                          That sucks. What kind of proof or chain of evidence is required? Stories like these is why I do not use ebay.

                          Comment

                          • tucocaps
                            Badcaps Veteran
                            • Apr 2013
                            • 331
                            • United Stated

                            #14
                            Re: Is it possible to bench test an inverter board?

                            Originally posted by SteveNielsen
                            Without a schematic for the board you still might be able to figure it out from the pinout and specs of the chip that is below the white connectors in your picture.
                            Not sure exactly what you mean by that. Based on my experience, I don't think I'll be able to figure it out from any information on the board itself.

                            Comment

                            • SteveNielsen
                              Retired Tech
                              • Jun 2012
                              • 2327
                              • USA

                              #15
                              Re: Is it possible to bench test an inverter board?

                              What I mean is,
                              does the chip have anything printed on it? If you can identify it you may be able to get a pinout of it and determine what voltages need to be applied where to operate it and possibly turn the board on so you can bench test it.

                              Comment

                              • selldoor
                                Slow Learner
                                • Dec 2010
                                • 7870

                                #16
                                Re: Is it possible to bench test an inverter board?

                                I may be wrong but I am not sure you should power up a board without lamps. I believe it might damage the inverters. In normal use the error detection from not having a bulb would switch off the power supply saving the inverters but using an external supply that would not happen. In any case without bulbs there has to be a limit to what you can test.
                                Secondary Voltages would be too high. I dont really think you can bench test it stand alone - that is without more parts, but I often think wrong
                                Please upload pictures using attachment function when ask for help on the repair
                                http://www.badcaps.net/forum/showthread.php?t=39740

                                Comment

                                • SteveNielsen
                                  Retired Tech
                                  • Jun 2012
                                  • 2327
                                  • USA

                                  #17
                                  Re: Is it possible to bench test an inverter board?

                                  I wasn't suggesting that. Find out what the thing is first. Knowing what the chip is, is a starting place.
                                  Last edited by SteveNielsen; 08-13-2014, 04:06 PM.

                                  Comment

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #18
                                    Re: Is it possible to bench test an inverter board?

                                    You will need 8 lamps and 24V power supply with current rating at least 7A.
                                    I never try testing the board by itself before but I will give it a try in the future since I have lots of spare power supplies.
                                    ftp://helpedia.com/pub/temp/datashee..._LTA400HM09_0_[DS].pdf
                                    Last edited by budm; 08-13-2014, 08:31 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

                                    • SteveNielsen
                                      Retired Tech
                                      • Jun 2012
                                      • 2327
                                      • USA

                                      #19
                                      Re: Is it possible to bench test an inverter board?

                                      Dead link Bud.

                                      Comment

                                      • SteveNielsen
                                        Retired Tech
                                        • Jun 2012
                                        • 2327
                                        • USA

                                        #20
                                        Re: Is it possible to bench test an inverter board?

                                        I have bench tested an inverter board from a laptop but it only required one CCFL tube connected to work (laptop had two tubes running from the same board connector in parallel) and I use it for testing individual tubes now. No matter what the inverter type is you will have to know where and what voltages to supply. There's Vcc supply voltage, enable signal voltage, dimming control voltage, etc. That's why the need for a schematic or at least the pinout & specs of the chip. Whether or not you need all 8 tubes connected or not for it to work is not known. It is possible but good trouble shooting techniques written up here suggest that it is not necessary; i.e. disconnecting tubes and trying to light one at a time to check for bad tubes, and the opposite; removing one tube at a time.

                                        Comment

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