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Transistor for Epson 1650 Photo Scanner?

Discussion in 'Electronic Repair' started by Jesse Hong, Feb 7, 2004.

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  1. Jesse Hong

    Jesse Hong Guest


    I'm trying to fix an Epson 1650 Photo scanner for a friend.
    It was dropped and the USB connector was yanked out of the
    PCB and appears to have sheared off a transistor right behind
    it. I have replaced the USB connector, but the transistor
    is no where to be found.

    Anyone happen to know what the "QF1" component on the PCB
    directly behind the USB connector should be? It looks to
    be wired through a resistor to the +5V pin of the USB on
    one lead, ground on another, and to a capacitor and more
    stuff on the third.

    I've done some searching, but haven't found anything, not
    quite ready yet to get a service manual just for this one
    piece of information which may not end up fixing it.

  2. BFriedl

    BFriedl Guest

    just thorowing my $.02 in, seems to be a voltage regulator for the
    scanner. Perhaps VCC is 3.3vdc, and not 5v in this case? IS the unit USB
    powered or does it have an external supply?

    A+ Certified Technician
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  3. Jesse Hong

    Jesse Hong Guest

    It is externally powered. I'm not that knowledgeable on
    circuits, but yeah, I also think it is probably part of a
    circuit to regulate current/voltage off the USB line...

    I'd like to try to get the exact part if I could, but
    if I had to experiment, I could just try getting any npn
    surface mount transistor and see if it works... and in
    that case, any educated guess might help.
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