What does it mean if iPod is doing this?

What does it mean if iPod is doing this?
I recently bought an ipod on ebay not realizing that the guy had put at the bottom: "Locked, it is tellimg me to connect to AC power and will not change." So what does this mean? I got it for an excellent price, so I am not going to attempt to return it, but would that be the hard drive or what? Just please don't lecture me on this decision, as I like vintage ipods better.

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