Tracking down short to ground

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  • October 16, 2016 at 2:58 PM #9114
    dfwarden
    Participant

      Could someone help steer me in the right direction to look for what I assume is a short to ground? I was checking the regulators per Verification step 1 on https://www.niksula.hut.fi/~mhiienka/ossc/diy-v1.5/assembly_tips.txt and discovered the only regulator correctly connected on my board is U6. On U5 the left pin appears correct but the right pin has a short to ground. All the other bottom-side regulators have both pins to the left and right of the middle ground pin connected to ground.

      I am still learning to read circuit diagrams but my intuition says that the position of the working regulators doesn’t help me narrow down the short. Is there something I should be checking first? I have checked the QFP chips many times for bridges and can’t find any, but perhaps I am not looking hard enough.

      October 18, 2016 at 10:52 PM #9168
      marqs
      Participant

        U5 drives inputs of all other regulators except U6, so you probably have a single short in DVDD3v3 line. I’d first carefully check all DVDD3v3/VCCIO/IOVDD pins which have a neighboring GND pin in all fine-pitch ICs – most likely there’s a solder bridge in one of them.

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