I have an Emachines desktop computer and everytime I plug my jump drive into the usb 2.0 ports, the computer just turns off after a couple of minutes. The desktop comes with 4 usb ports, 2 in front and 2 in back, and I tried all 4 ports and end up with the same problem. I have a printer connected to one of the rear ports and I use each of the ports on the front for my digital camera, and both devices work fine. Also, I have used three different brands of jump drives: san disk, pny, and lexar and they all cause my computer to just turn off after a couple of minutes. What may be causing this problem?
Are these devices powered from the USB cable itself or do they have external PSU's? USB has an inbuilt design threshold per port current limit which prevents too much power being drawn by external devices, and it may be that these devices when used cause an overload (not serious in scary high voltage terms, merely outside the spec) which causes the psu to reset.
Some motherboards have a built in current limiter which turns off just the USB device at fault and raises an event log message or screen dialog (win xp, 2000 etc) to that effect. Try running them off an external psu or externally powered USB hub.
Do you have access to other pc's and if so can u try connecting these suspect devices to one of the other pcs. Preferably a different branded pc with a diff motherboard design.
keith
January 2006
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