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Mosfet faulting

Discussion in 'General Hardware' started by ordi, Mar 20, 2012.

  1. ordi

    ordi New Member

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    Hello
    i have a toshiba A100
    and nothing appears good on it.
    No running, just blinking orange led.

    So i disasemble that laptop, and i test board and found some fuse and mosfet.
    Which one i have to change ?

    How to test a 8 legs MOSFET on laptop board mobo ?


    Thank :wtf:
  2. digibucc

    digibucc

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    find the schematics of the transistor, and then test each pin with a current to see if it passes the current through to it's matching pin. alternatively you could try it blindly, it would just take longer to find where each signal SHOULD go, then to figure out whether it's actually going there. it's usually the opposite pin, but you never know for sure and it can confuse things.

    example:
    http://www.youtube.com/watch?v=2BU7qHWtsmQ
  3. ordi

    ordi New Member

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  4. ordi

    ordi New Member

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    Maybe Q518 and Q519
    Transistor MOSFET
  5. ordi

    ordi New Member

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  6. digibucc

    digibucc

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    well the safer way would be to desolder it . you don't want to pass voltage through a trace you don't know about.

    regardless of how your laptop is behaving, the individual components can still be tested. there is no guarantee it's the mosfet or the same issue from the link you posted, but you have to start testing somewhere right?
  7. ordi

    ordi New Member

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    thank you digibucc
    but which one i have to desolder ....Q518 or Q519 ???
    or i have to test another cap or component ?
    Thanks
  8. ordi

    ordi New Member

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    it's about no power, no lights...
    Just when i plug the power supply on it, it's blinking orange led only...no contact.
    So it's for me a power problem (around mosfet, or fuse). But i test with and without voltage, the fuse but nothing wrong !!! And now i test mosfet and also, nothing to tell you !! Just to tell you what i have to test please !
  9. digibucc

    digibucc

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    hmm.. i'm afraid this is going beyond my knowledge... i will see if i can find anything though
  10. ordi

    ordi New Member

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    ok maybe it's the fuse. So how can i test it ?
  11. Bambooz

    Bambooz New Member

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    If you don't even know how to check a fuse, I'd say forget about fixing it. Give it to someone who knows what he's doing.
    You're almost guaranteed to damage something and make the entire thing unfixable, even for a pro.

    I've seen so many user-FUBAR'd electronics over the years it ain't funny anymore.
    (cut traces, damaged vias, accidental shorts destroying tons of parts, ripped-off solder pads, ...)
  12. ordi

    ordi New Member

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    http://img59.imageshack.us/img59/484/img20120322010512copie.jpg

    I check with power on, my meter to 20v DC, put the black lead to ground on the board, and i put the red lead to one end of the fuse, then put red lead to other end of the fuse, i saw 15,38V on both ends of the fuse. For the fuse near of the power socket...first pic.

    What do you think about this news ??
  13. ordi

    ordi New Member

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    ??
  14. Batou1986

    Batou1986

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    i know this sounds silly but have you tried it without the battery usually a blinking orange light is faulty battery.
  15. ordi

    ordi New Member

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    Yes i test this battery ? I found maybe IC bq24721 is faulting.
    What do you think about it ?

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