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Old first generation iPod “brick” required new battery 4 years ago that was swollen and preventing middle button from functioning. Apple retailer did repairs but now Apple is prohibiting their stores from working on discontinued products or even ordering parts. This is a relic that still works great. Appreciate any suggestions or options vs. purchasing a replacement.
Joe, first thing you want to do is to open it up. Use this guide for that. Discard the battery properly and of course replace with a new one. At this time I would consider replacing the click wheel. A replacement may be a bit hard to find, but they are still around. Follow this guide for that and as a last step remove the clickwheel. It is simply glued in to the front panel
I’m guessing you have an iPod Video 60GB. You can get the part from iFixIt: iPod Video 60/80 GB Battery Here’s the repair guide (make sure your iPod is the same as this before ordering the battery): iPod 5th Generation (Video) Battery Replacement