Is it possible to power an USB Hub from the computer's PSU?

Is it possible to power an USB Hub from one of the unused lines of the computer's PSU? For instance, can I use the floppy drive's 5V to power the hub directly?

Edit: I have tried to hook the hub directly to a 5V line from the psu (floppy connector), the computer won't boot and the dvd and hd lights keep flashing. I got a male molex connector from a broken floppy drive and found a plug that fits on the hub's power input. I checked for short circuits and correct polarization.
When I plug the hub (just the hub, nothing else on it), the computer won't boot. When I unplug the hub, it boots as usual.

sort by: active | newest | oldest
I personally (now) would avoid a project like this. I had somewhat the same idea. I got my hands on some cheap USB adapters for car power outlets. They need 12V, two lines on a standard drive connection are 12V. I took a hacksaw, cut off the plug on the board of a former CD drive, wired soldered & screwed it together, installed it into the open floppy disk slot (of which it fit PERFECTLY) and turned on my PC. I got no power to the outlet, then for no apparent reason, I got a good size spark out of it, and my system went off. I got all of the parts of the system in a dead state, I rebuilt the motherboard, & drives, so I was more concerned about the Mp3 player I had plugged into my hodgepodge creation at the time. But everything works fine. I was very cautions while wiring to not do anything that would be close to a short circuit, and yet, the project exploded in my face. (< not literally of course). If you continue working on this, don't underestimate how much power 5-12v really is.
It may well be then, that that particular hub is floating an external supply for some weird reason. You may be out of luck. Steve
lemonie6 years ago

I don't see why not, 5V is 5V, but you'd be technically-better by using a spare USB-riser off the mainboard.

Don't think so, because you can't get enough current from a single USB port to feed a maxed out hub. Steve
Well I read this as "Is it possible to power an USB Hub from one of the unused lines of the computer's PSU?"
You've sleuthed that this isn't actually the problem, and that there's some kind of USB-abuse going on. (good answer)

Don't see why not. It might be prudent to fuse it though