Odd situation that I have come across. One of my clients has a western digitial 500gb external usb hard drive. It has it's own power supply and was working fine for what I was told. Anyway, once it is plugged in all of the usb drives on the PC die. The usb mouse, laptop cooler, and usb speakers lose connection. After a quick reboot they all start working again. Now I know that when this happens its usually lack of power supply or a bad usb port. But any of them that I try it has the same effect. Also, it happens on my laptop as well when I tried to test it. Now before I tell them to consider it a loss and buy another external. Anyone with ideas?
1st guess ,A bad earth or a short. If You've used a different USB and it still dose it you could try a few things. When you power it up, do you hear the HD spin up? (light whir) -good Do a get a clicky sound -clickety-clickety-click-pause-lcikety... or total silence -bad. What sort of power connector dose it use? Standard round one like this? Can you get a similar style? Maplin or the like would do one for £5 or so. the final opttion is to get a new caddy, this one dose both sata and IDE 3.5 hd's. as you're in a different continent, please find your own more local supplier
tried runnning the thing whitout power supply? if it still kills the usb ports, you know it's not the power supply.and you should change the caddy. if it doesn't, you've got a suspect.
Try the drive behind a self powered hub. If it is a short, that will put the burden on the hub to switch on over current protection. It sounds like the drive uses a 3.5" drive internally so it almost certainly can't be bus powered. Make sure the external supply hasn't gone bad, the connector gotten loose, or some other thing like that. With USB mass storage devices, there are a number of transfers that do not have a transfer timeout specified. That means the PC needs to wait around a long time to be safe before assuming the drive is not responding. This can totally screw up the USB scheduler and your USB devices will stop working. So it is possible this is what is happening. Does the drive come up at all when you have it attached and you reboot? Can the BIOS see it, or will the computer boot at all?
