checking USB ports on motherboard for short?

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  • paparazzo79
    Badcaps Veteran
    • Dec 2018
    • 298
    • Bosnia
    #1

    checking USB ports on motherboard for short?

    Hi guys.
    Some of the USB ports on my motherboard malfunction.
    Usually devices connected on them either freeze while PC is in standby or get warning USB device not recognized.
    Is there a way (with multimeter) to check on USB ports on motherboard for short?
    I first want to make sure the hardware is either okay or malfunctioning before reinstall Windows 10 or drivers.
    Tags: None
    • harp
      Badcaps Veteran
      • Jun 2022
      • 598
      • Planet Earth
      #2
      Re: checking USB ports on motherboard for short?

      Is there a way (with multimeter) to check on USB ports on motherboard for short?
      Yes, but before do visual inspection inside of usb port... sometimes power pins got lifted and touch ground shield.

      Otherway, on left is ground, in center two data pin and on right is about 5Vdc. You can check that with multimeter.
      Attached Files

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        • DynaxSC
          Badcaps Veteran
          • Apr 2021
          • 458
          • Poland
          #3
          Re: checking USB ports on motherboard for short?

          Hi,

          Usually you will find ESD protection devices very close to the USB connectors, they look like the attached picture, have very different markings, but all do the same. There are also sometimes similar devices with more legs, generally slightly smaller.

          This ESD protection device is the first one to get shorted on a surge, usually they are able to protect the drivers behind (chipset or a dedicated USB driver).

          If you find a short, then replace this device first to see if the short is gone (orientation is important). If not, then chipset an/or the dedicated driver have to be replaced too (these devices unfortunately do not give 100% protection)

          You can also check for shorts on the active USB lines on this devices (the active USB data lines are connected to them directly), the two inner legs are ground, the 4 legs on the corners are the protected lines. This is much easier than trying to attach a probe on the contact inside an USB port. Measured resistance shuould be as I remember in Mohm's range. Also diode mode can be used to check/compare the USB ports.



          Same/similar devices also protect other connectors, eg. LAN/HDMI/DP, etc.
          Attached Files
          Last edited by DynaxSC; 01-01-2023, 11:27 AM.

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            • прямо
              Badcaps Veteran
              • Sep 2022
              • 261
              • Indonesia
              #4
              Re: checking USB ports on motherboard for short?

              Get yourself a USB male to DIP PCB module.

              It looks exactly like this.
              https://n11scdn.akamaized.net/a1/102...6653782183.jpg

              Plug that into the port and you can check the port with your multimeter probes. This is a lot easier than probing the legs of those tiny ESD diodes.

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