What is this little magnet for?

Discussion in 'PowerPC Macs' started by lPHONE, Oct 23, 2010.

  1. macrumors 6502a

    lPHONE

    Joined:
    Nov 17, 2009
    #1
    I have replaced many of LCD in PowerBooks and one of the things I noticed is after you remove the aluminum panel there's a little round magnet on the back of the LCD... What is this for?

    I have also seem a handful of cases where pressure applied to the back panel has caused this magnet to crack the LCD.
     
  2. macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #2
    It triggers the reed switch. The reed switch's job it to detect if the lid is open or closed.
     
  3. thread starter macrumors 6502a

    lPHONE

    Joined:
    Nov 17, 2009
    #3
    How's that even possible? This is in the center of the LCD where no circuitry is even close. Unless the magnet goes through the LCD and the trackpad and the reed switch is underneath?
     
  4. macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #4
    The switch is under the track pad. That little magnet is powerful enough to trigger the switch, even through the screen and track pad.
     
  5. macrumors 6502

    Joined:
    Oct 26, 2009
    #5
    That confused me too! Yep, it's the reed switch.
     

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