ipod classic (Late 2009) Slim 160GB not connecting/being recognised by various laptops, Apple and Windows.

I have an iPod classic which isn't being recognised. I plug it in the screen lights up but doesn't connect. The iPod charges fine and holds power but cannot connect to my Macbook. Currently running Tahoe 26.3.1. Cannot see the Ipod in finder or in itunes (Music). I have tried on an old macbook and on a windows but nothing. I have tried 3 different cables, all apple originals. The battery has been replaced. The 30 pin port has been cleaned and checked by a tech repair man. Is this a fixable issue or does this mean the end of the iPod?

Any advice would be greatly appreciated!