internal battery died of old age. I bought this old ipod in Japan in 2006? I was thinking it had had it and was considering reluctantly throwing it away! The I saw your ad and thought it was worth a shot ;)
Real struggle to get the case apart to be honest. The blade of both free tools were too flimsy and broke off fairly early on. Not sure I'd recommend - but I ended up using a blunt old knife (round ended cutlery knife) and managed extremely carefully to open the case (working around as per the instructions from headphone socket). Once the case was open, the rest was very staightforward. Switched it on - and the little red lights all came on. Brilliant!
First attempt - so not sure what I could have done better. Getting the case open was a real struggle. I may have lost a little patience and used an old round ended metal knife - you have to be really really careful with this - pushing it in but pushing toward the white plastic rather than the chrome back to avoid any accidental scratching - risky - but it did work for me (my ipod isn't pristine unfortunately so I wasn't too precious -just wanted it to work, and to be honest, it now works a treat. Massive kudos to iFixit though - really pleased. Awesome.