This may not be relevant, but it solved my problem when I thought my Rio 500 was broken. If you have a similar Mp3 player and are trying to use one of those Duracell Ultra batteries, don't. I noticed that the butt (the negative side) of the Ultra batteries is SMALLER than that of the normal copper top Duracell batteries. The result? The battery isn't long enough to touch both contacts in the mp3 player, thus, no juice.
If this isn't your problem and your batteries really are fine... then I suggest a quick trip to www.ebay.com or www.ubid.com
That's not the problem either. When a turn it on a faded screen shows up, following a "check battery" messge. I know the batteries fine, i just charged them. I even put in new batteries.
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