I have a 2.5' Laptop harddisk.
so, I bought a USB case for it to make it portable.
It works fine if I connected this portable harddisk
to my laptop's USB port.

However, it doesn't work if I connected it to a USB Hub.
Windows XP cannot detect it. My USB Hub is connected
to power supply.

any idea to solve this problem??

You should check your USB hub by connecting some other USB device to your computer through the hub. If the computer is not detecting this, then perhaps your USB hub requires a driver or a manual installation. Usually Xp should automatically detect this, but sometimes if the service pack has not been updated, then HI-Speed USB drivers will not be loaded and this may be a cause for concern/ problem. Can's seem to think of any oter reason this problem should occur.

here's another reason that it may not be working...and i speak from experience with my drives and cdroms. certain cases and hard disks---generally, the larger the disk, the more this applies--- require a healthy supply of power through the usb. certain 2.5 enclosures actually come with 2 seperate usb plugs, one for the data transfer, and the other for power supply. you may also notice that the 2 front usb posts on your computer don't handle heavy external drive enclosures well. The best bet for a properly working external drive is to plug it into the back of the computer where the onboard USB ports are... that way you have better power supply. Also the length of the cable can have an effect on the quality - the shorter the better. generally anything over 2 meters though is stretching the limit a bit. Going through a hub breaks down the supply even more, and you'll definitely have a weak connection unless the hub is plugged into a wall power socket in addition to the usb port

This post has been edited by Grafitti: Feb 22 2006, 12:47 PM

Yea I'd say Grafitti hit it on the nose. Those usb hubs often can't put much power out to their devices. I mean logically they usually cut one usb into 4, thus the power from the original usb hub is quaretered when it's pumped to the devices. A full 2.5 drive would take a healthy dose of constant power which a hub often could not provice.

Didn't know the cord length affected it though... learn something new everyday

(of course, this idea is irrelevant if the drive has it's on power adapter other then the usb cord...)

well i'm not 100% sure, but i think the accepted limit over which a usb wire retains an acceptable charge is 5 meters. but i would think that perhaps something like a printer would have trouble when over 2 meters distance, while a usb mouse could probably work at 6 or more. that part is simply speculation on my part, but i'd like to hear if anyone knows differently.

USB is connected but the Drive for it cannot be seen
Winxp Cannot Detect Usb Harddisk

Before, my computer can detect my USB and I can open the files in it. But lately, a friend use my computer and then the drive for the USB cannot be seen though there is an icon in the system tray. Anyone experienced this? Please tell how to solve it. Thanks

-Istambay

I got same problem
Winxp Cannot Detect Usb Harddisk

Replying to Feedbacker

I got the same problem with you feedbacker...I'm still looking for answers in the net. Keep me posted! Thanks


-Askal

usb power port output
Winxp Cannot Detect Usb Harddisk

My 2.5 USB external hard drive works on every other computer/laptop except my office desktop. I changed cables, still nothing worked. I tried another 2.5" USB hard drive on my desktop and it still did not work. Then I tried a 3.5" USB hard drive with external power and it worked... So I suspected the USB ports were not delivering enough power. I tried connecting my 2.5" enclosure to external power. I grabbed the Nokia charger beside me and plugged it in as the adapter end fits. My hard drive enclosure requires 5v dc/1A while the nokia adapter provides 5.7v dc/800mA. Lo and behold, as soon as I turned on the external power, the hard drive was then detected by XP and auto-played as normal as it does on other systems. I disconnected it quickly though as I fear the mismatch in voltage rating might damage the disk. So there you have it, as odd as it may seem, not all things work perfectly so check the power output of your USB ports or test using external power for your USB drive.

-reply by bojo

my usb hard disk not work properly on my pc
Winxp Cannot Detect Usb Harddisk

We operated xp 2nd edition. My usb harddisk drives is not working properl. & not see in my computer hard disk partition. Usb has 3 partition & not looking any partition. For solving this problem I am going to my computer properties / hardware / device manager / universal serial bus controller / click on scan for hardware changes this process asked the nu hardware found on your computer but the drives is not looking or not found what I do please explain me with easy process.

Ashish soni

-reply by ashish s. Soni