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Power and Display Query ???

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  • Power and Display Query ???

    As a part of my A+, while reading through my notes (Advent Training), I wonder if anyone could answer few of my questions about power & display issue?


    In laptop, there are two cables, one from wall socket to the box & other from the box to the laptop. Are these called AC (wall socket to box) and DC cable
    (box to laptop)? What this "box" officially called? Is it called PSU (or is this term only reserved for the PSU in PC?

    What is the purpose of this "box" rather than having a cable that connects directly from wall socket to laptop?


    In Dual-Scan/Passive-matrix Display, 2 transistors that intersect on the x-axis and y-axis control each pixel on screen. If transistor fails, entire line of

    pixels is disabled, leaving a black line across screen. To resolve this issue, do we HAVE TO replace the whole display or can replacing that particular

    transistor alone would resolve the issue? My notes says, "no way to repair this problem except to replace the display". Surely, we'd be able to replace a

    particular transistor rather than the whole screen?

    Similarly, in Active-Matrix Display, there are transistor for every pixel and each pixel is powered individually. Here, failure of transistor causes

    individual dead pixels. In such cases, is it possible to change the transistor or does the entire LCD require replacing?

  • #2
    Re: Power and Display Query ???

    My two cents:

    1. The cables and box are all part of the AC adapter. It is manufactured in multiple pieces to aid in manufacturing, storage, replacement.

    2. For all practical purposes you have to replace the entire display. Replacing a transistor is not something that could or should be done by a field technician. This would be done at the factory or authorized repair facility (if at all).


    • #3
      Re: Power and Display Query ???

      And mine:
      1) the "box" is an AC/DC adapter. Meaning, it gets the wall socket voltage as Input and the Output is the voltage (in most cases, like laptops, in DC) the specific product needs. That's why the first cable (from the socket to the "box") is called AC and the second (from the "box" to the laptop) DC. Like joeqwerty said, it is made of three distinct parts to be easier to be dealt with.
      2) I agree with joeqwerty. No serviceable parts in there...

      Sorin Solomon

      In order to succeed, your desire for success should be greater than your fear of failure.