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ThinkVision T2454p backlight but no display - blown SOT23-8

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    ThinkVision T2454p backlight but no display - blown SOT23-8

    This monitor turns on and activates backlight but displays no picture, this is a fairly common problem at work and I see a few posts about it on Lenovo's forum too.

    Now, I took one apart and there is a blown SOT23-8 which I think is a MPS MP2315 - my chip is marked 'AGCF' so I think I'm on the right track.


    I see I can buy this chip from Mouser but since this chip is a known problem with this monitor I'm wondering if it is possible to upgrade this chip with a superior variant that perhaps lasts longer/better specs ?

    Anyone with any input on this ?

    Thanks
    Attached Files

    #2
    Re: ThinkVision T2454p backlight but no display - blown SOT23-8

    How are the caps doing?
    When ESR rises regulators must do a much harder job.
    And eventually they can become overloaded...
    -Or, it could be a marginal part or a design mistake of course as you say.
    But it is more sensible to check the easy things first...
    "The one who says it cannot be done should never interrupt the one who is doing it."

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      #3
      Re: ThinkVision T2454p backlight but no display - blown SOT23-8

      Caps looks fine and esr seems fine measured in circuit.

      Only thing I did notice was that the powersupply silkscreen shows ouput as 16V to the MP2315, it measures 20.1V without anything connected to the powersupply. The 16V line is driven by a Excelliance Mos BA5N10A a brand not very common to me atleast.

      Supply voltage for the MP2315 is 4.5 to 24 with 28V as maximum so I guess it is fine even if 16V perhaps would make the chip run cooler instead of 20.1V, 5V line measures 5.2 so it's perfectly fine.

      I did order a few MP2315 so I will replace one and see what happens.
      Attached Files
      Last edited by Gabriel; 08-01-2020, 05:36 PM.

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        #4
        Re: ThinkVision T2454p backlight but no display - blown SOT23-8

        This is my follow up post:

        I ordered a few MPS MP2315 from mouser.

        Removed the blow'n MP2315

        and fitted a new one.

        2 new FR instead of Aishi.

        New FR next to the Elite GP polymer.

        Putting it back together.

        And it's back working as it should.

        The osd was locked but can be unblocked by holding in the 'back' button for 10sec.



        No caps on these boards was measuring out of spec but I fitted a few FR anyway.
        Attached Files

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