Help understanding USB powering for charging IPOD

[gaidensensei]

I had some trouble with getting an Ipod nano to work with a particular machine.

It works no problem on a laptop and separate desktop, but when I put it on another desktop, it would never get detected. I am not well versed in electrical engineering, so this may be a part of why I don't understand.

After messing around, I finally figured out what it was. Seems that it has to do with the power being supplied by the ports. Right now, I'm able to get the ipod to connect by using a logitech external usb speaker that has it's own power source and a hub built in on it.

So my question is, why can't I charge it from the ports in back of my current rig? AFAIK, everything is within spec.
I'm running 3 usb devices, 2 are a logitech keyboard and mouse, and the last is the speaker.

PSU is good and does not have issues (Antec True380), powering a mini-itx build of E8400 + zotac board with onboard Geforce 9300 and wifi, and a wd sata HD.

I've never had issues plugging in any other devices, so why is it the ipod has problems?

 

[corkyg]

What you have is taxing your 380 watt PSU pretty heavily. Combine that with general USB flakiness. As I see it, get a bigger PSU or use a different port that works.

 

[KeithP]

You could try unplugging all other USB devices except a mouse then connecting the iPod. If that works, I would guess that the motherboard is simply not supplying proper voltage on to the USB ports.

If that is the case, a powered USB hub may solve the problem.

-KeithP

 

[corkyg]

iPods tend to draw more current than other USB devices.