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Thread: Laptop Power Problem

  1. #1
    Senior Member tagg's Avatar
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    Default Laptop Power Problem

    Hi all, I have a small problem with a laptop its getting no power to the mother board, now i think i have found the problem, just behind the power plug connector on the motherboard i found a burnt out transistor (i think its a transistor) now it looks just like the transistor that has caused the no power to lnb on the DM500, The only markings on the chip is A7S, and i would like to try and find one so i can try and replace it.

    I have added a photo but its pretty bad as i only could use my phone.


    Last edited by tagg; 05-03-08 at 10:29 PM. Reason: bad eye sight



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    Senior Member BCNZ's Avatar
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    The closest match I can find for A75 is A7s, which is a BAV99 (dual serial diode BAW92).

    Somehow I don't think this is it. Then again, I don't know the circuit configuration for the power input side of a laptop!

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    Senior Member cwispy's Avatar
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    Could it maybe be A7S? If so its a BAW92 - "Matched Configuration Diode - Two Diodes,no common pins,IR max 5uA at VR 75V."
    What would you do if your server was stolen or failed beyond repair?
    http://www.2000cn.com.au/shadowprotect.html

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    What model laptop is it mate?
    When you do things right, people won't be sure that you have done anything at all

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    Senior Member tagg's Avatar
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    Studio1

    Bro i think you are on the money, i just recheck it with a mini mircoscope and it is a S not a 5 as i first thought, so now i need to get one from some where to test it

    Man the thing is small lol

    Thanks Cwispy you guys are right , So its a Diode not a transistor ??

    Tagg

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    Senior Member tagg's Avatar
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    best4less

    Dell Latitude D500, got it for free so i don't mind playing with it

    Tagg

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    Here is a link for the service manual
    You never know if your lucky enough to get
    a schematic in there?????????

    When you do things right, people won't be sure that you have done anything at all

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    Nope no circuit diagram
    Pfft they call it a service manual LOL

    sorry mate
    When you do things right, people won't be sure that you have done anything at all

  • #9
    Senior Member tagg's Avatar
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    lol yea i have been hunting the net for one but no luck, Do know of any online stores that i could get one of these from ?, as adelaide is pretty much stuff for parts like this

    Tagg

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    Senior Member BCNZ's Avatar
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    Jeez, it's hard enough finding wiring diagrams for Jap import vehicles - but for a laptop?
    I've NEVER seen one.. ever.

    Best of fortune in finding a replacement component.

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    So just solder in two diodes? as per diagram- can only be cleaning the ac input no?

  • #12
    Senior Member BCNZ's Avatar
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    Quote Originally Posted by tytower View Post
    So just solder in two diodes? as per diagram- can only be cleaning the ac input no?
    It's probably some kind of specialist diode that has certain characteristics that make it impossible to be replaced with a couple of 1N914s or such.

    Manufacturers have a knack of doing this just to screw you over.

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