USB Issues

[richard.thomas]

Hi,

I'm having a really weird problem with one of the computers in one of my primary schools.

 

Basically, if the printer is plugged in to it no USB drives will work on the computer (tried about 5 of different makes). This computer is a Dell OptiPlex GX60. We have quite a few of these so I’ve tried putting another base-unit in there only to get the exact same result.

The printer is a HP C3180 (All-in-one), we have 6 more of these printers, however, they're plugged into RMs- and without a problem.

 

I've uninstalled anything to do with USB from the device manager and restarted the computer to let it reinstall everything several times, even in safe mode for a few of them. I've also re-imaged the machine and still the problem persists.

 

Does anyone have any ideas as to why this is happening? For the moment I've told the teacher that they've just got to unplug the printer before they can use the USB key (which apparently is something she's had to do for quite some time- this is an issue I’ve inherited)

[SYNACK]

It may be that the USB hub on those computers is under-powered or single switching. If the printer is plugged in it will not request any extra voltage on the USB bus as it is self powered. If a USB drive is plugged in and the controller cannot switch up the power because it does not have the voltage or only has a single voltage switching mechanism (passive hub) it will not provide the necessary power to run the USB drive.

 

I had this problem on a really rubbish motherboard once where it did not provide enough voltage to run USB powered devices (old iMacs were actually designed with no USB power support for stuff like scanners).

 

Anyhow the fix in that case was adding a USB controller expantion card (PCI) which got around the underpowered controller. A way to test this out may be to connect a powered usb hub to one of the ports and then trying to connect both devices. If this works its the controller.

[pallen]

Have you checked to see if you have the latest drivers installed for the Dells? Or checked in the BIOS to see if there is a setting disabling the USB connections. Although I would have thought that would have prevented the USB from working at all.

 

Does it prevent you from using USB drives assigning a letter, or any device such as a scanner etc?

[richard.thomas]

I need to check the BIOS, but all the other drivers are up to date.

 

The printer and Promethean board work fine when they're both plugged in but as SYNACK suggests it could be a power issue as both of those are powered by good old fashioned plug.

The USB stick works fine when the printer is unplugged. And works fine when the ActivBoard is plugged in. It doesn't work fine if I just unplug the board but leave the printer in which kind of rules out the power issue?

 

I'll see if I can dig up a powered hub from somewhere.

 

Thanks for the suggestions