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short circuit in PCB

Avatar Posted by Tse Jian Ji at

    Hi,

    For school I need to make a project (audio scrambler)
    After I designed my project in SQL and translate to PCB, I see a short circuit at one of my ressistors. (R64)


    I've checked everything, and don't know what I've did wrond, and so have my teacher electronics.
    I think it has something to do with the ground, because I have a several grounds in my project.
    How should I connect them? Should I connect every ground with each other or use the '0V' component from the library?
    I've also alot of voltage points (by example several Ua , 12V or U/2) should I connect all the Ua with each other all the U/2 with each other etc...?

    Can someone help me please? That would be very kind!
    Thank You

    Attachments
    zTGZG.png
    zTGZG.png (307.25 KiB) Viewed 561 times
    eege.png
    eege.png (285.87 KiB) Viewed 561 times
    dvgzg.png
    dvgzg.png (419.04 KiB) Viewed 561 times

    Replies

    • Avatar

      Posted by Tse Jian Ji at

      red circle is the ressistor R64

    • Avatar

      Posted by Tse Jian Ji at

      .

      Tse Jian Ji wrote:red circle is the ressistor R64

    • Avatar

      Posted by Boss at

      Unfortunately I cannot see your pictures!

      Can you re post them one at a time each attached to their own reply (i.e. one per post). I think this let them be visible on the Forum.

    • Avatar

      Posted by Tse Jian Ji at

      eege.png
      eege.png (255.6 KiB) Viewed 266 times

    • Avatar

      Posted by Tse Jian Ji at

      zTGZG.png
      zTGZG.png (315.33 KiB) Viewed 265 times

    • Avatar

      Posted by Tse Jian Ji at

      Untitled.png
      Untitled.png (396.69 KiB) Viewed 265 times

    • Avatar

      Posted by Boss at

      Hi Tse Jian Ji,

      To investigate further, I would highlight the net in the schematic and check the net name. Do this for both sides of the resister R64 and check they are different. You can do this by "mouse over", but right click and select highlight net is the best overall view.

      I would also be tempted to delete R64 and check the nets are seperate as Ua and Ud are quite similar and could be easily typed wrongly in error.

      Let us know your findings.

    • Avatar

      Posted by Boss at

      Hi Tse Jian Ji

      Another area you need to correct is with regard to the 0V of the input filter/decoupling.

      On the Untitled.png you will see the 0V connected to the gnd side of C33, 34 and 35 goes to the 0V input and also off to the rest of the circuit implied by the gnd symbol. Looking at your schematic and indeed the PCB ratsnest you will see the above part of the circuit are isolated and do not go to to the 0V input or indeed the rest of the circuit.

      Hope that helps.

    • Avatar

      Posted by Boss at

      And looking back at your original question

      Should I connect every ground with each other or use the '0V' component from the library?
      I've also alot of voltage points (by example several Ua , 12V or U/2) should I connect all the Ua with each other all the U/2 with each other etc...?


      Yes, is the answer. The labels are there to allow the direct wire not be drawn, which would confuse the signal flow and function of the diagram. So this is probably your error that I saw and mentioned in the previous reply.

      By naming a net e.g. 0V all nets of this name become connected. (Hence the possible error causing the shorted resistor).

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