internal LCD power supply,Schottky Rectifier substitute question

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  • supersabre
    Member
    • Feb 2006
    • 45

    #1

    internal LCD power supply,Schottky Rectifier substitute question

    I just received a 17 inches lcd from my friend
    ,but it keeps on/off, the green led keeps blinking on and off.

    I bypass the internal power supply and power the lcd up using an
    external power supply and the lcd works great.

    If the internal power have no load(not connected to video board), the
    12V output is stable.
    But once it connected, the voltage keeps jumping up and down

    I suspect the Schottky Rectifier is bad, since i replace almost everything in the secondary

    The Schottky Rectifier is 100V , 10A, mbr10100ct,Dual Common-Cathode High-Voltage Schottky Rectifier

    https://www.ortodoxism.ro/datasheets...y/mbr1090c.pdf

    However, i can't find the same one in mouser or digikey.

    Will this work? MBR20100CThttp://www.onsemi.com/pub/Collateral/MBR2060CT-D.PDF ???

    Digi key part number:MBR20100CTGOS-ND

    What are the important things when replacing the Rectifier? voltage? Amp?
  • kc8adu
    Super Moderator
    • Nov 2003
    • 8832
    • U.S.A!

    #2
    Re: internal LCD power supply,Schottky Rectifier substitute question

    i doubt the schottky is bad.
    if it passes ohmmeter test look to caps.
    i replace all with high quality low esr.

    Comment

    • supersabre
      Member
      • Feb 2006
      • 45

      #3
      Re: internal LCD power supply,Schottky Rectifier substitute question

      I did not replace the caps since they all rubycon, the esr are also good for them.
      I replace almost everything except the output Schottky Rectifier and caps. Rectifier (dual diodes)passes the ohm tester, but the 12V output to the video board is very unstable(voltage jump up and down)

      What are the important parameters when replacing the Rectifier? voltage? Amp?

      Comment

      • kc8adu
        Super Moderator
        • Nov 2003
        • 8832
        • U.S.A!

        #4
        Re: internal LCD power supply,Schottky Rectifier substitute question

        yes.
        i doubt you need anywhere near 100v though.
        i like twice the output voltage.
        vf is lower on lower voltage parts so less heat.
        you can try a schottky but i lean toward caps or a feedback problem.
        got a scope?
        look for trash on the output.

        Comment

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