iPod overheat when charging, then it's dead

Hello all,

This is my first question here, looking for some confirmation on my findings.

I have an iPod 3rd Generation 64 GB which its battery was depleted and when I put it to charge it started to overheat a lot, at the back bottom of the device. Needless to say, I could not make it work afterwards, not even in DFU or anything.

I found the below, which suggest some cleaning an ultimately a battery replacement:

Why did my iPod overheat?

From a local store I have been told the "Dock assembly" needs replacement.

What do you think? Does it sound like the battery or dock assembly? If the second, can you point me to where I can get some parts?

Kind regards,

Lani.