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Circuit Board Defect - or USB

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  • David Bedard
    When I got my circuit board I did a quick QA inspection and found no errors but when I got to the USB power supply section I nound a deep burr or abrasion on
    Message 1 of 2 , Dec 6, 2010
    When I got my circuit board I did a quick QA
    inspection and found no errors but when I got to
    the USB power supply section I nound a 
    deep burr or abrasion on the circuit board on
    the trace between C2 and R10 (top side) which cut 
    the connection between output of the USB
    power supply and the rest of the board.
    Horrors! A dead PCB board!! Not hardly says I. 

    I considered wireing in an AWG32 shunt
    directly over the trace, thereby retaining the
    full 250ma capability of  the regulator but got lazy and
    decided that I could get away with a bridge
    soldered over the gap after scrapping off the PCB
    lacquer. Sure, this reduces the thickness of the
    trace and introduces two non perfect junctions. I figure
    this will cut the current capacity of the trace by at least
    one half. Now, if the unit is only going to use up 250mw average
    power it should not be a problem but If more than 300mw is going to be
    used up by the USB interface then I think it will be safer to add the shunt wire.
     
    Anyone have an idea on what the power use will be for the USB portion
    of the circuit?
     
    See attachment for pictures of bridged trace, and elements on the opposite side.
     
    KB3VBK
    Charles

    ---------------------------------------------------------------------------
    "I've never killed [anyone], but I've read many an obituary with a great deal of satisfaction." - Samuel  (Mark Twain) Clemens
     
  • Alan
    ... From: David Bedard BTW... ... If you look at Wikipedia it says it is of American origin. But I m not suggesting you believe everything that says! I ve
    Message 2 of 2 , Dec 7, 2010
      ----- Original Message -----
      From: "David Bedard"


      BTW...
      > anyone know why Brits say "keep a stiff upper lip"?


      If you look at Wikipedia it says it is of American origin. But I'm not
      suggesting you believe everything that says!

      I've always thought that it just meant to show no emotion, a trembling upper
      lip is the prelude to tears.

      73 Alan G4ZFQ
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