3 Replies Latest reply on Jun 14, 2011 7:34 AM by Flying_Kiwi

    D945GSEJT USB port back panel differences?  Power?

    r10kindsofpeople

      Are the three USB ports on the back panel of the D945GSEJT different in some way?  Perhaps in how USB power is managed?

       

      We're finding that when we plug two devices (one a USB mini-monitor, the other a USB flash drive) into the horizontal connectors, the motherboard sometimes gets stuck at the BIOS screen.  Moving one of the devices to the third (vertical) connector seems to solve the problem.  Would love some confirmation of this, particularly since the problem is intermittent, and perhaps some simple way to test the devices to confirm that they're within the USB spec and find the margins.

       

      John

        • 1. Re: D945GSEJT USB port back panel differences?  Power?
          Curious592

          Vista is more problematic with USB detection.  If you have any unknown devices in device manager USB devices this can interfere.  Those should be uninstalled before removing the device in case your USB monitor or key normally shows up for safe removal.  The monitor should be powered on before startup.  Power management does power down unused ports which could affect other devices.

          • 2. Re: D945GSEJT USB port back panel differences?  Power?
            r10kindsofpeople

            The OS is Ubuntu 10.10, and the Intel BIOS screen is still displayed when the system locks up so I'm skeptical that the OS is part of the puzzle.  I suppose I could try unplugging the SATA drive to see if it locks before or after the "no OS found" message.

             

            The USB monitor is powered through the USB port, so "ON" is controlled by the USB power.

             

            I've done testing with only two devices (monitor & flash) and three devices, and either combination seems  to work as long as the monitor and flash are not both plugged into the horizontal connectors.  But the problem is intermittent, so this could be a false indicator.  Next time I power it on, it could fail even with one of them in the vertical connector.

             

            John

            • 3. Re: D945GSEJT USB port back panel differences?  Power?
              Flying_Kiwi

              r10kindsofpeople wrote:

               

              The USB monitor is powered through the USB port, so "ON" is controlled by the USB power.

              Those USB powered mini monitors require quite a bit of power from the USB port so I suspect (especially given the intermittent nature of the problem) that it's power related. Your poor wee board gets all its power through either one of the two 12 V inputs (internal or external). Do you have another USB device that you can test with (which isn't another flash memory storage device as that board only supports one of those via USB and which isn't so power hungry as a mini monitor)?

               

              Alternatively, you may have a method of powering the board through the 'other' power supply input, (as long as you don't attempt to use both at the same time). When a certain manufacturer first came up with a USB powered flat panel scanner, many people ran into problems using it with other USB devices for the same reason. It may have been (just) within specs for USB port power consumption but that didn't stop it reaking havock with many systems that utilised USB devices heavily. FWIW I don't think its at all OS related.

               

              It'd also be worth having a look on the mini-monitor manufacturers website to see if theres a firmware upgrade for it.