How does USB power work?
By definition, USB supplies a maximum of 2.5 watts of power per port (5 volts at 0.5 amps). Thus, if you are using a USB port that is connected directly to your computer, you will probably be able to charge your iPod. However, if you are connecting through a USB hub of some sort, then it may not charge, especially if the hub is not powered externally via an AC adapter. After all, a non-powered hub is plugged into only one USB port on the computer itself (or another hub, for that matter) and, thus, would have only 2.5 watts of power coming to it from that one port and would not be carried downstream to the ports on the hub itself. In fact, a non-powered hub typically delivers only about 0.1 amps (20% of the USB standard's power) to its ports, thus most definitely not enough to tickle your iPod's fancy.
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My recommendation is to make sure to plug your iPod directly into the computer rather than through any hub. Also, make sure that your computer is using USB 2.0 ports as iPods historically have not liked USB 1.1 and, as such, have shown limited (and erratic) functionality on USB 1.1. If you are not sure what you have in your computer, feel free to contact me by private message with the brand and model of machine and I can tell you what you have. ybarra-cgm.com
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If you have too many USB devices and must have some attached through a hub, then make sure that it is a powered hub (it has its own AC adapter) and that it is a USB 2.0 hub. I will attach some models to this answer as I finish it. copyright ybarra-cgm
If it turns out that you have only USB 1.1 in your computer, then I would suggest buying a USB 2.0 host adapter, which I will attach to this answer in just a moment, to give yourself the functionality needed for the iPod. copyright ybarra-cgm
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Now finally, if the iPod is connected to the port on your computer and was previously charging but is no longer, then try switching to another port and see if it charges again. If so, inspect the previous port for damage. USB ports are notoriously fragile: the plastic blade in the center can easily be broken out and, thus, remove the support for the internal contacts which will, of course, cause questionable or no electrical contact to be made between the cable end and the port itself. The only option to repair such damage is to replace the motherboard. However, with most motherboards nowadays having so many USB ports built in, avoiding that one and using another will probably be the best (not to mention cheapest, as it is free) option.
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This issue is not caused by a driver since this is a function of the hardware itself. Thus, any driver updates that you have done recently will not have effect on the charging capability. The same is true for any updates done to iTunes or to the iPod’s firmware itself. ybarra-cgm.com
Another possibility is that the cable itself is damaged. If you have another cable handy for your iPod, then swap it out and see if the problem goes away. Those cables are not very expensive, so should you need one, you can get it easily enough. ybarra-cgm.com
Without seeing it personally, these are the only items I can think might cause your problem. If you have any questions, feel free to drop me a line. I’m glad to help. ybarra-cgm.com
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