Megmeet MIP390HW power supply problem

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  • cheeky2
    Badcaps Veteran
    • Dec 2012
    • 337
    • uk
    #1

    Megmeet MIP390HW power supply problem

    I have this Megmeet MIP390HW power supply which had some blown components after a mosfet shorted out. I have replaced the blown resistors R40, R41, R42, R26, R32 and the mosfet Q4. The main fuse T5A was also replaced.
    However I cannot seem to find a schematic for this power supply to identify U1 which I believe is blown as a result of the resistors vaporising together with the mosfet.
    I have attached a close up of a working psu together with the blown board before replacing components.
    I don't have any standby 5V which I suspect is down to U1. So any help with identifying the IC U1 or schematic for this Megmeet MIP390HW from a Technika 39C273 tv would be great.
    Thanks
    Attached Files
    Tags: None
    • budm
      Badcaps Legend
      • Feb 2010
      • 40746
      • USA
      #2
      Re: Megmeet MIP390HW power supply problem

      It nay be NCP1250.
      Looking at your board lay out, the connections of the IC's pins seem to match with NCP1250.
      1 = gnd
      4 = CS
      5 = VCC
      6 = Gate drive

      BTW, it also matches FAN6862-D, SG6858.
      Attached Files
      Last edited by budm; 11-17-2018, 06:29 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

        • R_J
          Badcaps Legend
          • Jun 2012
          • 9551
          • Canada
          #3
          Re: Megmeet MIP390HW power supply problem

          Another one might be a OB2262, any numbers on the ic of the working power supply ?

            Comment

            • cheeky2
              Badcaps Veteran
              • Dec 2012
              • 337
              • uk
              #4
              Re: Megmeet MIP390HW power supply problem

              Great thanks for the input.
              I took the pictures of the working psu before the TV was sold. Thinking about it I could get the microscope out and examine the old one to see if I can get some numbers off it. It appears to have lacquer over it which might make it a little tricky to determine what it is. Any thoughts as to an easy removal of the lacquer without damaging the information on the ic?
              I will keep you updated on how it goes with pictures...

                Comment

                • cheeky2
                  Badcaps Veteran
                  • Dec 2012
                  • 337
                  • uk
                  #5
                  Re: Megmeet MIP390HW power supply problem

                  Ok here are the pictures of the ic! It doesn't look to be any of the suspected ics as it is marked KvP amongst other things. Over pin 5 it looks like part of the ic has blown a small hole in it which is where R26 and R32 were open circuit.
                  I am now trying to identify this ic picture attached.
                  I removed the lacquer with white spirit, my finger nail, toothbrush and cleaned up with isopropanol.

                  I didn't have any success with KvP but as soon as I searched for 37R came up trumps.
                  Datasheet attached.
                  Now off to order it
                  Attached Files
                  Last edited by cheeky2; 11-18-2018, 05:08 AM.

                    Comment

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