Music won't play, just directly pauses

I’m trying to revive an old iPod 5.5 80gb. Everything works except it won’t play music - it syncs and updates from iTunes, it charges and the battery is fine for it’s age. The click wheel is working, it can go in and out of menus and selects perfectly fine. Except when I try to play music it just goes straight to pause. If I click play it shows the play icon but there’s no movement on the progress bar.

I have done all the resets and diagnostics, and even replaced the drive cable but didn’t fix the issue.

Reluctant to junk this as it’s the version with the Wolfson DAC. Help?