USB B powered fan

[whitelime]

ok so i have a hard drive dock that has both usb and esata. i only use the esata port so i have no use for the usb port in the back on the dock so i decided to turn it into a usb fan to cool my hard drive that when it is in the dock. I just striped it and hooked up the black and red wire like shown here be instead of using a usb A i used a usb B so that it can hook up to the back of the dock.

http://www.metacafe.com/watch/701904/usb_powered_fan/

i also tried using the other end (usb A) and it worked perfectly. my guess is that USB B doesnt provide power?? but it has a ground and a 5+ (red and black wire) so ideally it should work just like a USB A. sounds like a good idea, but sadly it didnt work. wondering if anyone got this working or have insight as to why it isnt working.

 

[r_manic]

I know USB B ports provide power, since my olllllldddddd iOmega Zip Drive connects to the cable through a USB port. It doesn't require external power to work.

I also don't understand why your setup didn't work, when both USB A and B use the same four cables anyway... maybe you accidentally let the two cables touch each other during setup?

 

[whitelime]

i was told that the USB B doesnt carry power, it recieves it. and that the reason why its not working. The power comes from the computer throught USB A and usb B recieves it. I guess im stuck will using USB A from my computer to power the fan. thanks for the reply