7 Replies Latest reply on Oct 17, 2018 10:03 PM by yuaanliie

    short circuit in pcb board

    drishya

      how to solve if there is a short occured in pcb board?

        • Re: short circuit in pcb board
          uscdadnyc

          There are multiple "Yes" answer(s) to your Q. (1) Yes, there are/were Current Trace(ing) Probes. I have (since 1979) a Triplet HP (Hewlett Packard) Probes: (a) Logic Probe, (b) Logic Pulser, (c) Current Tracer. (2) IF the PCB is Only Two-sided, then you can "cut" Traces on your PCB, and/or unsolder (one-end) of components, in an effort to Isolate the "short".

          IF you live in the NYC area, I can lend you use of my Current Probe. Here again I ask e14Commenters to post their physical location (Country), so I can suggest solutions based on their location. I know that the UK/EU have differing Laws on Privacy, but stating (your) country is not that intrusive. This coming from an US Patent Attorney, me.

          USCDADNYC (NY NY USA)

          • Re: short circuit in pcb board
            jw0752

            Hi Drishya,

            When I used to encounter shorted conditions on a circuit board I would make small cuts in traces until I could isolate the problem. Once the problem was isolated and repaired I would go back and solder bridge the cuts to repair proper continuity. In rare circumstances I would use a wire jumper to go around a problem.

             

            John

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            • Re: short circuit in pcb board
              radcliffkaty1

              In order to solve the short circuit which is occurred on the PCB, firstly you need to trace that short circuit. If you have something that can measure very low resistances, you can use this to track down a short. The closer you get to it, the lower the resistance will be.

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              • Re: short circuit in pcb board
                koudelad

                Hello,

                 

                There is also a popular way using a current limited power supply and IR camera / alcohol etc.

                 

                Get as close to the short as possible and connect the power supply (or simply replace the original power supply if you have no idea, where to start). Set the voltage supply to a meaningful value and current supply to ca. few amps to 10 A.  The place, where the short occurs will get hotter than the rest of the board. It can be a trace or a component. If you have access to an IR camera, do some images. Alternatively, pour over some alcohol and see, where it evaporates first.

                 

                Have a look at this video from Louis Rossmann, A guy repairing Apple products. It is quite a long video, feel free to skip to the actual process.

                 

                https://m.youtube.com/watch?v=t5fICjcaJ3E

                 

                David

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                • Re: short circuit in pcb board
                  yuaanliie

                  Not sure whether you are trying to test a bare PCB board for shorts or whether you are trying to locate a bad component on a loaded board.

                   

                  It is easy to find nets that are shorted together on a bare board because the resistance will be low when it should be high. Actually finding the short is harder, because most ohm meters can’t really measure the difference between two very low resistances.

                   

                  Finding a bad component is easiest if you have a known good board to compare. You can measure the net to net resistances on one and compare them to another.

                   

                  On a board with active components, you can also get better measurements by using an ohmmeter with a rather low test voltage, less than the switching threshold of any active parts on the same nets.

                   

                  Thanks & Regards,

                  Yuaan Liie

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